Prepare Flights

User Manual — Weather & Airport Information for Pilots

1. Welcome & What This Is For

This is a browser-based weather and airport information tool for general-aviation pilots. It puts every significant airport worldwide (over 22,000 of them) on one map and overlays it with a complete suite of aviation weather forecast products — current conditions, multi-day forecasts, fog, icing, turbulence, and convection — so you can answer the questions that matter before a flight: Is the weather flyable? Where? When?

The app is a Progressive Web App: open it in any modern browser, optionally add it to your home screen, and it behaves like a native app (works offline for basic map content, full-screen on mobile).

What you can do:

• See the current flight category (VFR / MVFR / BIR / IFR / LIFR) of every airport at a glance
• Spot fog, mist, and freezing fog as letter badges right on airport markers
• Read the latest METAR and a 12-hour TAF with one click
• Click anywhere on the map for a compact weather panel and 6-period day/evening/night forecast
• Scrub forward up to 7 days through every forecast layer using a single time bar
• Draw a line on the map and instantly see a vertical weather cross-section (an airgram) along it
• View animated wind, cloud, precipitation, fog, icing, turbulence, convective activity, and pressure forecasts as map overlays
• Read official Significant Weather Charts (SWC) and live SIGMETs alongside the model forecast

2. The Interface at a Glance

The main screen is intentionally clean. Here is every control you will see and what it does:

That's the entire UI. The map fills the rest of the screen.

3. Moving Around the Map

• Pan — click + drag (touch: drag)
• Zoom — scroll wheel, pinch, or use the + / − buttons
• Reset to your location — click the ◉ locate button

Smaller airports become visible as you zoom in — large airports are visible globally, medium ones from zoom 5, small ones from zoom 7.

4. Searching for Airports

Click the search bar at the top-left and type at least two characters. Matches appear as a dropdown. You can search by:

• ICAO code — EFHK
• IATA code — HEL
• Airport or city name — Helsinki

Pick a result and the map flies to the airport and opens its popup automatically.

Quick list (no typing). Tap the empty search box and a shortlist drops down before you type anything:

• Nearest — the closest airports to your location, each with its distance in nautical miles. This uses your device’s GPS, so allow the location permission when asked; if no position is available the Nearest list is simply omitted.
• Favourites — your starred airports (Section 6.7), shown when you are signed in.

Tap a row to jump straight to that airport and open its popup — and unlike a typed search, the zoom level stays as you had it (only the map centre moves). Tapping the search box again closes the list.

5. Airport Markers

5.1 Marker Types & Visibility

5.2 Live Flight-Category Colour

Whenever a current METAR is available, the dot is replaced by a larger category badge with a single letter inside:

The worst-case rule applies: whichever value is in the lower category wins.

Map weather refreshes itself: a background pull runs about every five minutes, plus an immediate refresh when you pan or zoom to new airports and when you return to the tab after it has been hidden for a couple of minutes. The bottom-right corner shows an “Updated N min ago” indicator, colour-coded green (under 5 min) → amber (under 15 min) → red (older), so the age of the marker colours is always visible. To force a fresh pull at any time, click the ↻ Refresh button in the bottom-left button column.

Small fields without an official METAR can still get a category colour from a nearby unofficial observation (an on-field automatic weather station, or the nearest station within range) — see Section 6.6. Those markers are flagged as estimates so they are not mistaken for an official reading.

5.3 Fog & Mist Badges

If the METAR contains a fog/mist code, a small coloured tag appears under the airport identifier:

5.4 Filtering Which Airports Show

The funnel button sits at the top-left of the map, stacked directly under the ★ favourites button. Click it to open the Filters panel; the panel floats above the map controls so nothing hides it. A live “N / M shown” count at the bottom tracks how many of the loaded airports pass your filters, and a Reset button clears everything back to defaults.

All filters combine (an airport must pass every active one to stay on the map). Favourite airports are exempt — a starred field stays visible even when its type or size is filtered out.

• Type — Large, Medium and Small airports (all on by default).
• Runway — Min / Max length — two sliders that bound the runway length (a field passes if it has a runway in the chosen range). The min slider’s left end and the max slider’s right end both read any, so leaving them at the extremes places no limit; the two are kept ordered so the minimum can never exceed the maximum.
• Paved only — restrict to hard-surface (asphalt / concrete) runways.
• ATC service — tick any of TWR, APP/TWR, AFIS/Radio, CTAF/UNICOM, Uncontrolled; leave all unticked for any.
• Country — one or more comma-separated ISO codes (e.g. FI, SE, EE); blank = any.
• Max elevation — hide fields above a given field elevation in feet.
• Fuel — show only fields with JET A-1 or AVGAS, and optionally hide PPR-required fields. Fuel / PPR data comes from cached AIPs.

Your filter selections are remembered between sessions. When you are signed in (Section 16) they also sync to your account, so the same set follows you to every device and browser.

6. Airport Information

Click any airport marker. The popup opens centred on screen and auto-pans if it would otherwise be clipped at the top edge. Long popups become scrollable inside their card rather than pushing past the viewport.

6.1 Header

The header is two rows that read like a quick-look briefing:

• Row 1 (left): Airport name · current flight category pill (VFR / MVFR / BIR / IFR / LIFR) · NOTAM badge ("N", orange/red) when active NOTAMs exist.
• Row 1 (right): Open-Meteo "now" snippet — temperature, weather icon, plain-English condition (e.g. "Partly cloudy").
• Row 2 (left): ICAO · IATA codes (greyed monospace).
• Row 2 (right): Surface wind — direction° / speed kt (e.g. "240°/12kt"), same small grey style as the codes.

6.2 Tabs

Below the header a row of tabs gives access to deeper information. The default tab is Info. Tabs are only shown when their data is available.

6.3 Weather Tab

The Weather tab stacks five clearly separated boxed sections. Each section has a coloured top stripe identifying its data source.

The METAR and TAF section headers each carry a small ↻ refresh button. Clicking it bypasses every cache layer and pulls the freshest report straight from the source — useful when an observation is overdue and you want to check for an update without reloading the page. The popup also refreshes its own METAR on a timer while it is open, and the age timestamp turns amber, then red, as the reading gets older, so a stale value is obvious at a glance.

An "Active weather layers" verdict block appears at the bottom of this tab when any forecast layer is on (Winds, Icing, Turbulence, etc.) — same content as in Section 7.

6.4 How Icing is Detected

An icing badge appears whenever any of these is true:

• The METAR contains a freezing-precipitation code (FZRA, FZDZ, FZFG, …)
• Temperature is in −20 … +2 °C AND there is precipitation (RA, SN, DZ, PL, SG, GR, GS)
• Temperature is in −20 … +2 °C AND ceiling ≤ 5,000 ft AND temperature−dewpoint spread ≤ 3 °C (visible moisture in clouds)

This is a deliberately permissive trigger — icing certificates require margin, and the cost of a false negative is far higher than a false positive.

6.5 METAR History — the Last-3h Trend

The METAR section header has a History button. Open it to reveal a compact trend of the last three hours of observations — up to six columns at the routine half-hourly cadence, oldest on the left, the most recent marked NOW on the right. It uses the same visual grammar as the TAF timeline: a coloured flight-category letter per column, then rows for WND, VIS, CIG, WX / CB and QNH. Hover any column to see its raw METAR line.

The point is to show how the weather is actually evolving rather than just the single current reading — is the ceiling lifting or lowering, is visibility improving, is the wind backing or building? Read side by side with the TAF section directly above it, the trend lets you sanity-check the forecast against what the field has really been doing: a TAF calling for improvement carries more confidence when the last three hours already show it, and a deteriorating trend against a steady TAF is a flag to watch.

The trend is offered both for fields with an official METAR and for fields whose unofficial observation we archive ourselves (Section 6.6). The panel loads on first open and is kept for the rest of the popup session.

6.6 Unofficial Weather at Fields Without a METAR

Many smaller fields publish no official ICAO METAR. Where a usable observation exists nearby, the app surfaces it anyway — clearly labelled so it is never mistaken for the real thing. A banner above the decoded weather always states the source and that it is “unofficial — not an ICAO METAR”.

The distance rule behind this: a station within about 1.5 nm is treated as the field’s own weather; a station out to roughly 27 nm (~50 km) is offered only as a labelled nearest-station estimate; beyond that nothing is shown. This is why two neighbouring grass strips can differ — one has an automatic station close enough to qualify and the other’s closest station falls just outside the range.

These unofficial fields also support the Last-3h trend (Section 6.5), archived from our own snapshots. As with every product here, treat unofficial readings as situational awareness and verify against official sources before flight.

No METAR / TAF at all — the Open-Meteo model estimate. When a field has neither an official report nor a usable nearby station, the METAR and TAF sections simply read “No METAR available” / “No TAF available” followed by a pointer: “See Open-Meteo model estimate for METAR / TAF below.” The Weather (Open-Meteo) section (Section 6.3) then supplies a fully model-derived OM-METAR and OM-TAF in the same visual grammar as the real reports. This gives useful situational awareness for fields the observation network does not cover — but it is a numerical-model estimate (the same data behind the forecast layers), never measured weather, so it is labelled accordingly throughout.

6.7 Favourite Airports

Mark the airports you check often as favourites and reach them — with their weather at a glance — in one tap. The ★ button is visible to everyone; saving favourites requires you to be signed in (Section 16), after which they sync to your account and follow you across every device. If you open the panel while signed out, it explains the feature and offers a one-tap sign-in.

• Star an airport. Open any airport’s popup and tap the ★ star next to its name. A filled star means it is a favourite; tap again to remove it.
• The Favourites panel. A ★ button sits at the top-left of the map, just under the “Show my location” control, and opens a panel next to it. Each row shows a flight-category badge (VFR/IFR/…, same coloured pill as the popup), the ICAO and name, and at-a-glance weather chips — ceiling, visibility and wind. Fields without their own METAR borrow an estimated category from the nearest station or the on-field/AWOS reading, shown in italic.
• Jump to one. Click a row to pan the map straight to that airport and open its popup. The zoom level stays exactly as you had it — only the centre moves.

Removing a favourite is done from the airport’s popup (tap the star off), so the panel always reflects the set you actually use.

7. Click-Anywhere Weather

Click an empty spot on the map (anywhere that is not an airport) to open the weather panel for that point. The popup auto-pans into view if its top would be clipped, and becomes scrollable inside the card when content (especially after generating an AI summary) is taller than the viewport.

7.1 Header

The header mirrors the airport popup layout but with location data instead of airport identifiers.

• Row 1 (left): Reverse-geocoded place name (e.g. "Mikkeli"). Falls back briefly to "Loading location…" while the geocoder responds (1.5 s timeout).
• Row 1 (right): Temperature, weather icon, plain-English condition.
• Row 2 (left): Latitude / longitude in decimal degrees (e.g. 61.690°, 27.270°) followed by the terrain elevation at that grid cell (m and ft, Copernicus DEM via Open-Meteo). Useful context for minimum safe altitude when clicking on terrain.
• Row 2 (right): Surface wind — direction° / speed kt.

7.2 Sections

Below the header the popup stacks boxed sections in this order. Each has a coloured top stripe identifying its data source. The order is deliberately Open-Meteo first because it covers the whole planet, then LLF only when the click point is inside a Nordic forecast area.

7.3 Active Weather Layers

When forecast layers are switched on, a section labelled Active weather layers appears at the bottom of the popup. Each active layer (Winds, Clouds, Icing, Turbulence, Convective, Precipitation, Fog, MSL Pressure) contributes a one-line verdict for the click point. Verdicts respect the selected altitude and the current time-bar offset, so the popup tracks both inputs in real time.

• Turbulence — "Moderate turbulence — wind shear 5.0 kt/1000 ft between FL100 and FL140 — low altitude band (around FL050)". Cells flagged with the wx-layer-ctx-warn tint when severity is MOD or worse.
• Icing — "Severe icing (large supercooled droplets possible) — temperature −4 °C, humidity 100%, cloud cover 100% at flight level 100".
• Other layers follow the same pattern: layer name on the left, value+verdict on the right.

This section is your fastest cross-check that the painted overlay matches the underlying data at a specific click point.

8. The Time Bar — Scrubbing Forecasts

Whenever a forecast layer is on (or an airspace overlay needs simulated-time scrubbing), a time bar appears at the bottom of the map. It controls all time-aware overlays simultaneously, so you can sweep through "what does Friday morning look like over the Baltic?" in seconds.

The range is approximately −12 h ↔ +168 h (7 days). Past observations are limited by the source (e.g. radar nowcasts only publish a recent window). When no time-aware layer is on, the bar hides itself; turning a forecast layer off snaps the time back to Now automatically so the next layer you open doesn't inherit a stale offset.

9. The Altitude Bar

Some forecast layers (Clouds, Icing, Turbulence, Winds, Precipitation, Convective Activity, MSL Pressure) are inherently three-dimensional. A shared altitude bar appears in the top-right whenever you switch on a layer that needs one. Picking a level applies it to every active 3-D layer at once, which keeps cross-comparisons honest.

Low / Mid / High are non-overlapping bands — the same shear layer or icing cell appears in exactly one of them, never two. Hover any button for a tooltip explaining what it represents and which pressure levels it draws from.

The bar hides itself when no altitude-aware layer is on and resets to Total automatically so the next altitude-aware layer you open starts in its default state.

10. Map Layers (🌐)

The globe-icon menu in the top-right corner controls the underlying basemap style and two essential airspace overlays. Open it by clicking the globe; click any other layer-menu icon (or anywhere on the map) to close.

10.1 Basemap

Pick one of three vector basemap styles. All three are rendered by MapLibre GL JS from OpenStreetMap data via OpenFreeMap, so they zoom smoothly to any level and stay sharp on high-DPI screens.

10.2 Terminal Airspaces

What you see: TMA and CTR polygons around controlled airports, outlined and shaded subtly so they don’t bury the underlying map. Click any polygon to open a popup with the controlling unit’s callsign, primary frequency, vertical limits and airspace class.

How it’s computed: Vector airspace data pulled live from the OpenAIP airspace API for the visible bounding box. Cached per-bbox so panning back to a recently viewed area is instant.

Use it for: Knowing whose airspace you’re entering, getting the right frequency before contact, and judging the lateral and vertical limits of controlled volumes on your route.

10.3 Special Use Airspaces

What you see: Restricted (R), Danger (D) and Prohibited (P) areas plus TSA / TRA reservations (military training, daily AUP/UUP releases). Two independent visual channels encode type and activation:

The hourly scrubber on the time bar updates the styling live, so scrubbing forward shows which areas switch from dashed to solid (or vice-versa) at any time in the next 24 h. Click a polygon to read the activating NOTAM(s), validity window, vertical limits and remarks.

How it’s computed: Combines three sources for the widest practical coverage:

• OpenAIP for the published R/D/P geometry across Europe.
• Flyk for a Finland-extended R/D/P set (broader local coverage than OpenAIP) and for NOTAM-supplement-driven temporary areas that are created and modified at short notice.
• Flyk AUP/UUP feeds for TSA / TRA reservation calendars — refreshed daily and re-evaluated against the current hour to set activation state.

Use it for: Active-airspace avoidance, planning around military exercise blocks, finding the right NOTAM number before phoning ATC, and knowing in advance which areas will reopen during your flight window.

10.4 ACC Sectors

What you see: Area Control Centre sector boundaries drawn as thin dark-grey dashed outlines. Each sector is labelled with its name and primary frequency. Click any sector to open the unified What’s-Here popup with the sector callsign, all available frequencies, vertical limits and remarks — same chip/tab layout as the SUA and Terminal popups, so clicking through stacked airspaces is consistent.

How it’s computed: Sector geometry comes from three sources merged transparently:

• Flyk for Finnish ACC sectors (14 sub-sectors, AIRAC-current).
• Local AIP-derived files for Sweden, Estonia, Latvia, Denmark.
• OpenAIP (type=27) for the rest of Europe / Turkey / Cyprus.

Use it for: Knowing which ACC to contact and on which frequency at any point along your route; especially useful for IFR pickup and for VFR flight following in busy airspace.

10.5 IFR Points

What you see: Published IFR enroute fixes (waypoints, intersections, navaids referenced by the IFR network) drawn as small magenta triangles with five-letter identifiers. Click a point for full details. Visible only at zoom levels where the names won’t overlap.

How it’s computed: Live vector data from flyk.com's aeronautical waypoint feed, cached per bbox.

Use it for: Reading IFR clearances, planning controlled-airspace transit corridors, and matching FPL route strings against the visible network.

10.6 VFR Points

What you see: VFR reporting points published in national AIPs — the official compulsory and on-request fixes used to enter / exit CTRs and TMAs. Each point shows its short name (and sometimes a one-letter code) on the map.

How it’s computed: National AIP / Flyk waypoint data, displayed at the zoom level where labels remain legible.

Use it for: Building VFR routes that the controlling unit will recognise (“requesting EFHK transit via OSCAR”), confirming the geometry of a published reporting point before reporting overhead, and aligning your GPS plan with the names ATC will use on the radio.

10.7 GPS Interference

What you see: A coloured hex-grid highlighting areas where aircraft reported degraded GPS / navigation accuracy — a likely sign of GPS interference (jamming or spoofing). Only meaningful cells are drawn: yellow = Medium (2–10 % of aircraft in the cell affected) and red = High (>10 %). The low/clean tier is omitted to keep the map focused on actual interference.

How it’s computed: Built from gpsjam.org’s daily resolution-4 H3 dataset, which is derived from ADS-B Exchange aircraft navigation-integrity (NIC) reports. The app shows the most recent available day, keeping only cells with at least five aircraft and more than 2 % degraded. The data is aggregated over a full UTC day — it is not real-time, and a coloured cell indicates detected degradation, not a confirmation of intentional jamming or spoofing.

Reading it: Turn the layer on from the World menu. A legend appears in the bottom-left legend panel (ⓘ button) with the date and colour key. Click any cell — or anywhere on the map — to open the unified “What’s here?” popup, where a GPS chip shows the interference level, the affected-aircraft percentage and counts for that cell, alongside the usual airspace, alert and weather chips.

Use it for: Situational awareness of regions where GNSS reliability has recently been poor (e.g. near conflict zones), so you can plan for the possibility of GPS loss — brief conventional-navigation fallbacks, expect RAIM/approach degradation, and cross-check position. Because it reflects the previous day, treat it as a trend indicator, not a live warning; always check current NOTAMs for active GPS outages.

11. Weather Forecast Layers (⛅)

Click the cloud-and-sun icon (top-right) to open the forecast menu. You can have several layers on at once. Every layer in this menu is computed from Open-Meteo model data unless noted, and every layer responds to the time bar (Section 8) and the altitude bar (Section 9, where applicable).

The legend panel at the bottom-right shows colour scales and on-screen tweaks for each active layer.

11.1 Winds

What you see: Animated particles streaming across the map at the chosen flight level. Particles flow in the wind direction; their density gives a feel for speed; speed is colour-coded (cool = light, warm = strong).

How it's computed: The forecast model's u and v wind components at the selected pressure level are sampled on a viewport-fitted grid. Particles are advected each frame using bilinear interpolation, with random respawn to keep the field "alive".

Use it for: Picking the most efficient cruise level, spotting frontal shear, judging crosswind for an airport.

11.2 Clouds

What you see: A smooth grey cloud-cover raster (GPU-rendered, so it zooms cleanly). The shading darkens and grows more opaque as forecast cloud cover rises. Optional category labels show the low / mid / high cloud amounts as WMO oktas (e.g. OVC / SCT / –, where “–” = clear), one per contiguous area; toggle them from the legend’s Show category labels checkbox.

How it's computed:

• Total is an altitude-weighted blend of the three levels (low cloud darkens the most, high the least), so the grey tone reflects which decks are present.
• Low / Mid / High use Open-Meteo's cloud_cover_low/mid/high directly (each shown at its own weight).
• FL050 … FL240 altitude-bar steps map to the containing slab (low / mid / high).

Use it for: Quick "is there a hole?" assessment, ceiling height awareness, comparing cloud cover at different cruise levels.

11.3 Precipitation

What you see: A GPU-rendered tint with animated rain drops / snowflakes overlaid. The tint colour ramps by rate, from pale blue (very light) through blue and dark blue to purple and red (extreme); snow washes the colour toward white; sleet is a mix. Forecast probability is shown as colour saturation — uncertain areas read greyer / washed-out, confident areas fully saturated. Opacity stays constant so even light-but-likely precipitation remains visible.

How it's computed: Open-Meteo's precipitation (mm water-equivalent per hour), snowfall (cm fresh snow per hour, ~10:1 ratio) and precipitation_probability are sampled on the grid. The ratio of snowfall to precipitation gives a "snow fraction" which controls the rain↔snow colour and symbol mix per cell; the probability drives the saturation. The animated drops/flakes fall by phase — blue rain streaks, white drifting snow, magenta freezing precip.

11.4 Temperatures

What you see: A smooth GPU-rendered heatmap of air temperature painted across the visible area, using the standard meteorological colour scale — violet for sub-Arctic cold, through blue and cyan into green, yellow, orange and red for hot regions. Temperatures sits at the bottom of the weather stack so clouds, precipitation, fog and other overlays render on top of it. The layer is altitude-aware: the altitude bar appears when it is selected — All shows the 2 m surface temperature, while Low / Mid / High and the FL050…FL240 bands switch the heatmap to the temperature at the corresponding pressure level (see How it's computed). An optional Show °C labels checkbox in the legend prints decluttered numeric values over the heatmap.

How it's computed: Open-Meteo temperature is sampled on the same shared 80×80 viewport grid as the cloud and precipitation overlays, so when several of those layers are on the data is fetched once and shared. The selected level picks the field: All uses temperature_2m; the altitude bands use the nearest pressure level — Low/FL050 → 850 hPa, Mid/FL100 → 700 hPa, FL140 → 600 hPa, High/FL180 → 500 hPa, FL240 → 400 hPa. Rendering is a WebGL raster: the temperature grid is uploaded as a texture and the GPU does the Mercator-correct bilinear sampling, while a 256-entry colour look-up texture built from the named stops applies the exact ramp — so the gradient stays smooth and the features anchored to the right geography across zoom and pan, with no per-frame CPU work. Switching level keeps the current frame on screen until the new level's data arrives (no blank flash).

Use it for:

• Icing exposure at low altitudes — sub-zero (blue / cyan) terrain combined with cloud-cover or precipitation overlays is the classic structural-icing setup.
• Density-altitude planning — orange / red regions (especially at higher elevation airfields) erode take-off performance dramatically. Cross-check with the airport's elevation and the DA62 perf calc.
• Air-mass boundary spotting — a sharp colour transition (e.g. a 10 °C drop over < 200 km) marks a thermal front. Pair with isobars (Section 11.9) to identify the synoptic feature.
• Time-scrubbing the warm/cold pulse — sliding the time bar shows the diurnal cycle and any approaching cold/warm advection in 1-hour steps.

11.5 Fog

What you see: A GPU-rendered raster where surface visibility is forecast to drop below 5 km. Four severity bands are classified in the shader and rendered as distinct blue-grey tones — no colour blending between bands, so edges are sharp:

BR in sub-zero temperatures is not classified as FZFG — freezing mist at 1–5 km is an observation nuisance, not a safety hazard, so the layer reserves the FZFG colour for genuinely fog-grade visibility.

Annotations (legend radio): Three options control what is drawn over the raster:

• None — raster only, no text or glyphs.
• ═/≡ Symbol — METAR-style glyph (single-bar for BR, double-bar for FG/DENSE, with a freeze marker for FZFG) placed at the cell centre. Uses the same declutter logic as other symbol layers so dense grids don't overlap.
• Visibility m — numeric read-out at each cell: metres for values below 1 km (e.g. 400 m), kilometres for 1–5 km (e.g. 2.3 km). Useful for quick CAT I/II/III minima checks. Decluttered with a slightly wider spacing than symbols.

The choice is saved and restored the next time the layer is switched on.

How it's computed: Open-Meteo's surface visibility (m) and temperature_2m (°C) are fetched on the same shared 80×80 viewport grid as the Clouds, Precipitation, and Temperature layers (48 h horizon; Nordic area uses MetNo Seamless). Classification is done entirely in the WebGL fragment shader — each pixel is assigned to exactly one band, with no interpolation between bands. At Now, the grid is then blended with live FMI observations — FMI's weather::simple AWS visibility readings and METAR visibility from every airport in view — using inverse-distance weighting within ~75 km of each observation. This pulls coastal-fog banks the model misses (Russarö, Utö, etc.) into the right place. Forecast hours use the model only. The layer is surface-only and does not have an altitude selector.

Use it for: Spotting valley-fog risk overnight, identifying freezing-fog corridors in winter, picking a safe diversion when your destination is below CAT 1 minima.

11.6 Icing

What you see: A GPU-rendered orange / red / magenta raster at the chosen pressure level, indicating Moderate / Heavy / Severe icing risk. Light icing is intentionally hidden — pilots don't plan around it and painting it drowned out the more serious bands. Optional horseshoe pictograms (∪ for moderate, ∪∪ for severe) can be enabled from the legend toggle; in the multi-level slabs (Total / Low / Mid / High) each pictogram also carries the FL band where the icing was detected.

How it's computed: Risk is non-zero only when:

1. Temperature at the level is in the supercooled-water window — full risk in the prime band 0 … −12 °C, then tapering off down to −24 °C as the cloud progressively glaciates (below roughly −15 °C the droplets increasingly freeze to ice crystals, which don't ice the airframe) — and
2. Cloud cover at the level is ≥ 50% (visible moisture is required for ice accretion).

A relative-humidity boost increases severity at high RH. The model draws from a slab of pressure levels — "Total" takes the maximum risk through the column; "Low / Mid / High" sample the corresponding slabs; FL050…FL240 sample one level each. A 3×3 averaging pass smooths single-cell hot spots. Temperature, humidity and cloud cover are fetched on the shared 80×80 viewport grid (48 h horizon), and the risk field is drawn as a WebGL raster — the colour comes from a GPU look-up table so it stays smooth at any zoom.

Freezing rain / SLD. The layer separately flags supercooled large droplets (freezing rain / drizzle) — the most hazardous icing, which the SWC calls out specifically. It detects the classic structure of a warm nose aloft (a layer above 0 °C) sitting over a sub-freezing, near-saturated layer near the surface. Such cells are forced to the severe band and marked with a distinct violet ∪∪∼ freezing-rain glyph (Total / Low slabs).

Use it for: Choosing a non-icing FL, knowing whether to file an alternate with non-icing approach options, validating route icing seen in the airgram.

11.7 Turbulence

What you see: A GPU-rendered yellow → red → magenta raster at the chosen FL slab, flagging clear-air (CAT) turbulence. Light turbulence is suppressed; only Moderate and worse paint. Optional wavy-line glyphs (1 / 2 / 3 waves for MOD / HVY / SEV) can be toggled from the legend; in the multi-level slabs they also carry the FL band where the shear lives.

How it's computed: Vertical wind shear is computed between closely-spaced Open-Meteo pressure-level pairs (25–50 hPa apart) so a thin shear layer isn't averaged away. Wind, wind direction and temperature for the slab's levels are fetched on the shared 80×80 viewport grid (48 h horizon) and the severity field is drawn as a WebGL raster (GPU colour look-up, smooth at any zoom). The shear in knots per 1,000 ft is mapped to the FAA's standard turbulence scale:

The raw shear severity is then refined by three physically-motivated steps, so the layer flags where the shear is actually likely to break into turbulence rather than every windy gradient:

• Richardson stability factor. Shear severity is multiplied by a factor derived from the Richardson number (N² / shear²): full weight in dynamically-unstable air, strongly damped in a stable, sharply-stratified layer where the same shear stays smooth.
• Boundary-layer suppression. Pairs sitting inside the model's boundary layer (the layer height is fetched per cell, so the cut adapts to a shallow nocturnal layer vs. a deep daytime one) are damped hard. The wind gradient there is the expected surface-friction profile, not free-atmosphere CAT — this removes the blanket of spurious low-level turbulence the layer used to show.
• Convective gate. Severity is raised only where convection has actually fired (CAPE and precipitation present together) — an intense cell (CAPE > 1500, precip > 5 mm/h) forces at least Severe, weaker cells at least Heavy/Moderate. Bare CAPE with no precipitation no longer paints, so the whole warm sector is no longer flagged.

Each altitude band (Low / Mid / High / FL050 … FL240) reads the worst refined severity across the pressure pairs within that band. All (Total) is the union of every band's pairs, so it always shows the worst turbulence anywhere in the SFC…FL390 column — never less than the individual band beneath it — with the glyph's FL label telling you the altitude.

11.8 Convective Activity

What you see: A single combined, GPU-rendered overlay covering everything convective. The colour encodes two things at once:

• Hue = severity: violet (TCU) → deeper violet (MOD CB) → magenta (STRG CB) → hot pink (SEV CB). The purple/magenta family keeps it distinct from the blue precipitation and orange turbulence layers.
• Vividness = active vs potential: a vivid, saturated cell is where the model forecasts a real convective cloud (or a thunderstorm code); a pale grey-violet wash is bare CAPE potential with no cloud developing yet (“loaded, not triggered”).
• Labels on the active cells: TCU, MOD CB, STRG CB or SEV CB, each with the real cloud-top flight level read from the model (e.g. FL340) — not an estimate.
• A lightning-bolt on each active storm cell that is thundering (WMO 95/96/99, or strong CAPE + LI) — one bolt per storm, above the label.

How it's computed: The layer samples Open-Meteo's DWD ICON model on a viewport grid — cape (Convective Available Potential Energy, J/kg), lifted_index (LI, °C), convective_inhibition (CIN, J/kg, negative = atmospheric cap), weather_code, and convective_cloud_top / convective_cloud_base (the actual forecast cloud, used for the “active” test and the top FL). The CAPE/LI/CIN values run through a continuous severity function with three guard-rails:

• CAPE-gated LI: Lifted Index can sharpen severity within a CAPE-supported tier but cannot promote a low-CAPE cell to severe-CB on its own. Pure LI without energy paints as TCU at most.
• SEV requires real energy: The severe-CB (red) tier needs CAPE ≥ 2500 J/kg, or CAPE ≥ 1500 paired with very steep LI (≤ −7). This stopped the previous "morning CAPE accumulating under an inversion" pattern from painting SEV when the cap was still intact.
• CIN attenuation: Strong negative CIN (< −50 J/kg) smoothly down-weights severity by up to 75 %. The classic "CAPE 2500 + CIN −200 → capped, no storms yet" case now paints faintly rather than as severe CB.

The weather code acts as a floor so observed showers / thunderstorms register even when the modelled CAPE/LI are mild. The whole field is anchored to world latitude/longitude, so pan and zoom never move the patches relative to the ground.

The CAPE/LI ranges above set the severity tier (hue); the top FL printed on each label is read directly from the model’s forecast convective cloud top, so it reflects the actual modelled cell rather than a CAPE/LI estimate. The “typical top FL” column is just the rough range you’d expect for each tier.

Caveats — what CAPE alone can and cannot tell you: CAPE is a potential, not a forecast that convection will actually happen. A capping inversion (CIN) can suppress it entirely; sparse triggers can leave it unused; vertical shear decides whether storms organise. Treat the layer as "where the atmosphere is loaded" — cross-check against radar, satellite and SIGMETs before launching when severity reaches MOD or higher.

11.9 MSL Pressure

What you see: A GPU-rendered, colour-filled pressure field — a diverging blue → white → red scale (deep blue for low pressure, white near the 1013 hPa standard, red for high) — with thin isobars drawn on top and H / L letters (and their core value) at the pressure centres. A legend radio lets you choose what's drawn: colour only, isobars + H/L only, or both (the default). The choice is remembered.

How it's computed: Open-Meteo's pressure_msl is sampled on the shared 80×80 viewport grid and drawn as a WebGL raster (the colour comes from a GPU look-up table, smooth at any zoom). A marching-squares pass extracts the isobars (4 hPa interval); a connected-component search finds the high- and low-pressure centres.

Use it for: Reading the synoptic situation — tightly spaced isobars mean strong wind, a closing "L" pattern means a deepening low.

11.10 SIGMETs/Warnings

What you see: Two complementary sources of issued (non-model) hazard polygons in one overlay:

• International SIGMETs — significant meteorological information from national MET offices: severe turbulence, severe icing, thunderstorms, volcanic ash, dust storms, etc. Coloured by phenomenon. A small arrow with a speed label is drawn from each polygon centroid when the raw SIGMET text carries a MOV direction + speed (e.g. MOV E 25KT); STNR SIGMETs get no arrow.
• FMI national weather warnings — CAP (Common Alerting Protocol) warnings issued by the Finnish Meteorological Institute, in English. Yellow / orange / red MeteoAlarm severity. Localised Finland-specific events (strong wind, snow load, freezing rain, thunderstorm, forest fire, frost, etc.) that complement the international SIGMET feed.

The polygon outline encodes activation timing — same SUA-style convention as Section 10.3: solid = active right now; dashed = activating later today or tomorrow. Polygons are only drawn when they are active now or activate within the next 24 h (already-expired entries and far-future ones stay hidden), so the layer reflects what is operationally relevant.

Hover any polygon for a compact two-line tooltip — a small severity pill on top and the event headline beneath. Click for the full popup: issuing source, validity window in UTC, phenomenon / event headline, plain-English description, peak wind / probability parameters, and the altitude band (SIGMETs only).

The unified time bar (Section 8) appears whenever the layer is on. Scrub forward to watch dashed polygons flip to solid as their activation windows open — useful for planning a flight window around an incoming warning.

How it's computed: Both feeds are pulled live, not model-derived. International SIGMETs come from the NOAA Aviation Weather Center isigmet feed. FMI CAP warnings come from alerts.fmi.fi/cap/feed/rss_en-GB.rss via the app’s server-side proxy (/fmi-warnings); the en-GB <info> block is selected so the popup text reads in English even when FMI also publishes fi-FI / sv-FI variants. Both refresh every ~5 minutes.

12. LLF Menu (Nordic Low Level Forecast)

Where to find it: the dedicated LLF button on the top-right control stack (directly below the SWC button) — LLF used to live in the Weather menu but is now its own control with four independently togglable sub-layers.

LLF is a Finnish Meteorological Institute product covering Finland, Sweden, Norway, Denmark and the Baltic. Polygons depict aviation-significant low-level conditions (vis < 8 km, ceiling < 2000 ft, icing, turbulence, CB/TCU) updated every ~30 minutes. Outside the Nordic LLF coverage the menu still works but every sub-layer will simply be empty.

12.1 Sub-layers

The FMI national CAP weather warnings (yellow / orange / red MeteoAlarm severity for strong wind, snow load, freezing rain, thunderstorm, forest fire, frost, etc.) live in the SIGMETs/Warnings overlay alongside the international SIGMET feed — see Section 11.10.

The three intensity-band badges (turb · ice · CB) are stacked vertically around the polygon centroid so they never overlap the G/L vis-cld cross at the same spot — turb above, ice below, CB further below.

12.2 Popup details

Click any LLF polygon to open the detail popup. Rows include flight category (G + L when local differs), VIS, CLD, present weather (decoded), 0°C freezing level, cloud TOP, ICE, TURB, CB/TCU, plus an "Active weather layers" verdict block. All band-type rows (ICE, TURB, CB) are filtered by point-in-polygon against the actual click location, not just the LLF area code — a sea-fog band 200 km offshore no longer surfaces in a coastal popup.

12.3 How the airport-popup LLF table relates

The Weather tab's Low Level Forecast section (Section 6.3) draws from the same FMI endpoints. The category row uses "G" for area and "L" only when local data shifts the category; VIS and CLD use FMI's bucket convention ("blw 1.5 km / 3 km / … / 8 km+", "blw 500 / 1000 / … / 2000+ ft"). Outside every returned sub-polygon the airport is treated as implicitly VFR (vis 8 km+, ceiling 2000 ft+) — matching FMI's convention of returning only non-VFR polygons.

How it's computed: FMI publishes the structured GeoJSON feed via ilmailusaa.fi (endpoints vis-cld, ice, mturb, cb, ctop, zero, wnd, overview). The app re-renders polygons locally and never mixes in model-derived data — everything in the LLF view is FMI's own forecast.

13. Significant Weather Charts

The SWC button (top-right) opens a small panel with three tabs:

SWCs are the official aviation-meteorology summary — jet streams, fronts, CB tops, icing/turbulence zones — and remain the gold standard for go/no-go decisions on longer flights.

14. Radar / Satellite Menu (📡)

14.1 What it is

The radar-dish icon (📡) on the top-right control stack opens the observed-imagery menu. Unlike the Weather forecast layers (Section 11), every entry here is a near-real-time tile from an external WMS feed — pick whichever you need and toggle them on independently. Layers tagged (FMI) are sourced from the Finnish Meteorological Institute (ilmailusaa.fi / openwms.fmi.fi) and only cover Finland and the Baltic; the others are pan-European or global.

14.2 Available layers

All seven layers above ship to every user.

14.3 Time control for observation layers

When any radar/satellite layer is on, the unified time bar (Section 8) switches into observation mode tailored to short-cadence imagery:

• Fine-step buttons — the bar shows extra −15 / +15 minute buttons either side of the time label. The ±6 h buttons (« / ») hide in this mode because observation data only extends back ~2–3 h.
• Backward / forward clamp — the time offset is clamped to the most-permissive active layer's data window. Try to scrub further back than the data supports and the corresponding step button greys out instead of letting the bar drift off the end.
• Layer pills — small chips at the right end of the bar list each active observation layer with a short code (Radar, FMI, Ltng, CB, ETop, Sat, VIIRS, Fog, Turb) and a colour cue: green when the current offset is inside that layer's data window, red when outside. Hover for the full layer name plus its data window in hours.

Approximate data windows per layer:

If you also turn on any forecast layer (Weather menu), the bar reverts to mixed mode: ±6 h steps reappear, ±15 min hides, and the layer pills now sit alongside a Forecast-aware longer range (−12 h…+7 d).

14.4 Reading the colour palettes

Each painted layer carries its own palette — the same RGB value means different things on the radar overlay vs. the lightning heatmap. The table below pairs each layer with what its colour ramp actually encodes; ramps are listed from weakest to strongest.

Cross-checking tip: when verifying a CB forecast, the painted intensity in Radar / Radar (FMI) tells you how heavy the precipitation is, while Storm tops tells you how tall the cell is. A bright-magenta radar return at FL300 storm-top is a fully developed CB; the same magenta radar return at FL080 storm-top is just a stratiform-rain bullseye and far less hazardous.

15. The Airgram Tool (↗)

An airgram is a vertical cross-section of the atmosphere: distance (or time) along the X axis, altitude up the Y axis. It's the fastest way to spot icing, cloud, turbulence and convective layers along a route — before deciding which flight level to file.

15.1 Drawing a Route

The airgram-line tool supports multiple waypoints. The route can pass through airports or arbitrary map points.

Snapping

Tools while drawing

The tool adapts to the input device automatically — phones and tablets get the tap / pan / pinch flow, laptops and desktops get the click + drag-to-pan flow. A touch-screen laptop with a mouse uses the desktop flow.

15.2 Reading the Chart

The chart is built from Open-Meteo pressure-level data along ~16–60 samples spaced ~10 nm apart, interpolated bilinearly between samples and pressure levels. The Y axis is altitude from FL000 to the chosen Max (default FL300; FL250 / FL200 / FL150 / FL100 also available — see § 15.4 / § 15.7).

15.3 The Hover Popup

Hovering the chart (mouse) or tapping (touch) shows a context popup with the precise values at that altitude band and distance/time along the route. The popup adapts to which conditions are present — rows are added only when meaningful.

How to read the wind line

The wind row is the most condensed: e.g. 109° / 38 kt HW 27 / 27 LX means the wind is FROM 109° at 38 kt; relative to the segment's course you'll have 27 kt of headwind and 27 kt of left-crosswind. If HW is shown with a negative number it's a tailwind — e.g. HW −10 / 5 LX = 10 kt tailwind, 5 kt left crosswind. Crosswind sign convention: positive = from the right side of the track, negative = from the left.

What's not shown

Rows for clear-sky cells just show the header + wind + atmosphere lines — no icing/turbulence/convective rows are added when the hazard is absent. This keeps the popup compact so the rows that do appear are the ones that matter for that point in the route.

15.4 Panel Controls

The toolbar lives in two rows above the chart.

Row 1 (view + time + display options) carries the Side / Top toggle, the departure date+time scrubber, and two display selects (Scale, Max). Scale and Max apply to the Side view only and disappear from the row when Top is active.

Row 2 (flight-plan inputs + read-outs) has the cruise FL input, an IAS / TAS airspeed button with its number, and four read-only spans (Flight time, GS, Dist, Wind) computed from row 1 + 2 inputs and the per-leg winds.

15.5 Legend layer toggles

The legend at the bottom of the chart doubles as per-layer visibility control. Each named overlay (Cloud, 0°C, FL, Precip, Icing, Turb, CB/TCU, Wind) is a clickable button: a single click hides that overlay from the chart, a second click brings it back. Hidden items render in muted grey with a strike-through. Precip covers the rain / sleet / snow streaks and the RAIN/SLEET/SNOW top labels with cloud-base FL. Sky and Terrain are base layers and are not toggleable.

Hover-tooltip rows are not affected by toggles. Turning off the Icing overlay declutters the visual but the hover readout still says ❄ ICING wherever the underlying severity is positive — information stays accessible even when the colour wash is hidden.

Layer choices are ephemeral: never written to localStorage, and a full panel rebuild (e.g. fresh popup open or page reload) restores every layer to ON. Toggling is also a cache-free operation: the airgram re-renders from the already-fetched response data, so flipping a layer is instant and uses no network.

15.6 Turbulence rendering

Turbulence intensity uses the FAA shear scale (LGT / MOD / HVY / SEV), computed from vertical wind shear between sampled pressure levels. The overlay is drawn as diagonal yellow stripes over a bilinearly interpolated severity field in both distance and altitude — the same continuous-field approach as the icing blob — so the blob edges feather smoothly across pressure-level boundaries.

15.7 Vertical sampling and the Max FL cap

The airgram fetches Open-Meteo upper-air data at a set of pressure levels tailored to the chosen Max. Lower caps use denser low-altitude levels so VFR-band detail (FL025–FL100) is sampled finely; higher caps spread the same effort across the full troposphere.

Switching the Max cap changes the upper-air request (the cache key includes the cap), so a new fetch fires. This means the chart genuinely changes resolution rather than just zooming the existing data.

15.8 Per-airport airgram

The same chart is also available from any airport popup via the Airgram tab. The X axis becomes a 24-hour timeline anchored at the departure moment from the row 1 scrubber (so Today 14:00Z plots the next 24 hours from 14:00 Z onwards). Row 1 of the toolbar (departure scrubber + Scale + Max) is identical to the route airgram, and the legend toggles work the same way. Row 2 (FL / IAS / Flight time / GS / Dist / Wind) is absent because a single-point view has no per-leg geometry.

The Scale and Max selects share their localStorage state with the route airgram: a choice made on either view shows up on the other one the next time it opens. The departure scrubber state is ephemeral on both views and does not cross between them.

15.9 Closing

Click × in the panel header. The drawn line is cleared automatically and the airgram-line button returns to its idle state.

15.10 Save as Flight

The airgram panel’s action row has a Save as Flight button next to the print / maximize controls. Clicking it captures the drawn route — every waypoint with its lat/lon, the entered cruise FL and IAS/TAS, the departure-scrubber time, and the per-leg winds — and creates (or updates) a Flight in the Flight Planner (Section 18). The Flight Planner panel opens automatically with the new entry highlighted, ready for fuel planning, multi-leg expansion or a full print-briefing.

This is the bridge between quick what-if exploration (draw a line, read the airgram) and committing to a planned flight (fuel reserves, TOC/TOD, briefing). Re-saving an already-saved airgram updates the existing flight in place rather than duplicating it.

16. Signing In & Syncing Your Data

The map, weather overlays, METAR / TAF, airgram tool, NOTAMs, SWC and radar work without an account. Sign in to unlock the Flight Planner (Section 18) and to have your saved flights, aircraft profiles and weather-layer preferences follow you across devices and browsers.

16.1 The account button

A small person icon sits at the top-left of the map, next to the search bar. Click it to open the account menu:

• Anonymous (not signed in): the menu shows a sign-in form — Continue with Google on top, and below it an email field with a Send sign-in link button.
• Signed in: the menu shows your email address, a ⚙ Settings entry (Section 17) and a Log out button.

An About entry sits at the bottom of this menu in both states — signed in or not — opening the version, contact and disclaimer dialog (Section 17.5).

16.2 Two ways to sign in

• Google — one tap. The browser hops to Google’s consent screen, you approve, and you’re back on the map already signed in. No password to remember.
• Email magic link — type your email address and tap Send sign-in link. A one-time link arrives within seconds (check spam if it doesn’t). Tap the link on the same device and you’re signed in. Useful when you don’t want to involve a third party, or you don’t have a Google account.

Either way the result is the same account — first time signing in with that email creates it, subsequent sign-ins log you back into the existing one. Your session persists for up to a year on each browser; you only need to sign in again if you log out explicitly or clear your cookies.

16.3 What syncs to the server

When you’re signed in, the following travels with your account so it’s there on every device you use:

• Saved flights — everything the Flight Planner library shows: routes, per-leg fuel / wind / FL settings, the aircraft choice, the visibility flag.
• Aircraft profiles — your custom aircraft (call name, fuel capacity, TAS, burn, climb / descent perf), and any per-preset overrides you made to the built-in DA62 / DA40 / SR22 / C172 / PA28 presets in Settings.
• Settings preferences — weather-layer modes and symbol toggles (Section 17.1), Flight Planner defaults (default aircraft, reserve and taxi minutes, default flight rules), basemap choice and the active map-overlay set (Terminal Airspaces / SUA / ACC / IFR / VFR Points), and your airgram view preferences (Hours / Days mode, speed mode, scale mode, max FL).
• Airport filters — your funnel-panel selections (type, runway length, surface, ATC, country, elevation, fuel; Section 5.4).
• Favourite airports — your starred fields (Section 6.7).
• Presets — your saved map-layer viewpoints (Section 20.3).

The sync runs quietly in the background — on every reload, when the tab regains focus, and periodically while you work. There is no “Save” button to press.

16.4 What does not sync

• Map view state — current pan, zoom and time-bar offset. These reset to defaults per session.
• UI ergonomics — panel positions you’ve dragged, dismissed one-shot hints. These stay per-browser.

16.5 Logging out

Picking Log out from the account menu does three things in sequence:

1. Tells the server to invalidate your session.
2. Wipes everything sync-related from this browser’s local storage — saved flights, aircraft profiles, synced settings, the last-push marker. Anything left would have been a copy already on the server.
3. Reloads the page so the next person using this browser sees a clean anonymous session and the map you were planning on doesn’t hang around.

When you sign back in (here or on another device) everything is fetched fresh from the server, so nothing is lost — only hidden between sessions.

17. Settings

Open Settings from the account menu (Section 16.1) — the ⚙ Settings entry. The panel is a two-level master–detail: a Home view with cards for Display, Aircraft and Presets (saved map-layer viewpoints — Section 20.3), each of which opens its own detail page with a ← Back button. Close with the × button in the header, by pressing Escape, or by clicking outside the panel.

Settings is for signed-in users — every change there is written to your account and propagates to your other browsers on their next sync. (The About dialog is separate: it lives in the account menu for everyone, not inside Settings — Section 17.5.)

17.1 Display

One row per weather-overlay control. These are the same toggles you’d find buried in the legend strips of individual overlays — pulled out here so you can configure your defaults in one place once, and not have to fiddle with each overlay’s mini-toggles every time you switch a layer on.

• Cloud labels — show / hide the per-cell numeric labels on the Clouds overlay.
• Winds mode — barbs vs. arrows for the Winds overlay.
• Precip symbols — show / hide symbolic precipitation glyphs on top of the colour gradient.
• Fog labels — choose the Fog overlay annotation mode: None (raster only), Symbol (BR/FG/FZFG glyphs), or Visibility m (numeric read-out).
• Icing symbols — show / hide the icing-severity icons.
• Convective symbols — show / hide CB / TS pictograms on Convective Activity.
• Turbulence symbols — show / hide turbulence pictograms.

Changing a control here updates the live map immediately if the corresponding overlay is on, and the choice is remembered for next time the overlay is enabled.

17.2 Aircraft

The Aircraft page has three sub-sections.

Defaults. Four fields used by the Flight Planner whenever you create a new flight:

• Default aircraft — which aircraft to preselect on a new flight.
• Default reserve — minutes of reserve fuel for the per-leg fuel required calculation.
• Default taxi — minutes of taxi fuel for the flight-totals math.
• Default flight rules — VFR / IFR / — preselection for the leg’s flight-rules picker.

Presets. A dropdown lists the built-in aircraft presets — DA62, DA40, SR22, C172, C182, PA28 and a generic GA tourer. Pick one and you get two buttons:

• Edit — opens the full perf editor (next sub-section) pre-filled with the preset’s numbers. Anything you change is saved as an override for that preset — the next time you (or the Flight Planner) ask for “DA62” your numbers come back instead of the factory defaults.
• Reset — visible only when overrides exist. Drops the overrides and restores the built-in numbers.

Custom aircraft. Aircraft you’ve added yourself (e.g. OH-DAA, your own tail). Each row shows the call name, cruise TAS and burn, and has Edit and Delete buttons. A + New button at the top of the list opens a blank editor.

17.3 Aircraft editor

The editor is a single form. The performance fields drive the planning math; Registration and MTOW are optional and feed the per-leg Handling flight-announcement email (Section 18.7).

Reserve and taxi are not in this editor — they live under Defaults (17.2). The reasoning: reserve and taxi are pilot / operator preferences, not aircraft properties.

Save writes the aircraft (or override) to your account and refreshes any open Flight Planner picker in real time, so you don’t need to close and reopen the planner to use the new entry. Cancel discards changes and returns to the Aircraft page.

17.4 Autorouter (connect your account)

Connecting your autorouter.aero account lets the Flight Planner find and validate IFR routes and file flight plans under your account — routing and filing always run against your own autorouter login, never a shared one.

• Connect autorouter — opens autorouter’s sign-in (OAuth) in a new page; on return the screen shows ✓ Connected with the session expiry. This unlocks the ✈ Auto route, Validate route and flight-plan filing controls on every leg (Section 18.12).
• Manage filed flight plans — lists the flight plans filed through your account so you can review or cancel them in one place.
• Disconnect — removes the stored token; the routing / filing controls revert to a “connect” prompt.

If the session expires the screen prompts you to reconnect. The connection is per-account and follows you across devices when you sign in.

17.5 About

The About dialog shows the current build version and date, the author’s copyright and contact email, and the app’s disclaimer. It opens from the About entry at the bottom of the account menu (Section 16.1) — the same place whether or not you are signed in. (About is not inside Settings.) The version line is handy when reporting an issue, so it’s clear which build you were running.

18. Flight Planner

The Flight Planner is a full multi-leg flight-planning panel: aircraft profile, fuel reserves, per-leg wind, TOC/TOD computation, airport-popup-grade briefing for every leg, and a printable navlog. Open it with the small briefcase-style icon at the bottom-left of the map (stacked just below the airgram-line button). The panel docks on the left side; drag the header to reposition.

Aircraft profiles — your fleet plus any overrides on the built-in presets — are managed in Settings → Aircraft (Section 17.2). The Flight Planner’s aircraft picker reads from that list. Per-flight tweaks to perf can also be made directly on the leg row; those edits are local to that flight (see the info box at the end of Section 17).

18.1 Flights Library

The top of the panel shows the Flights library — every saved flight with a name, departure airport / destination summary, leg count, total distance and a small action row (rename, duplicate, delete, set as current, Print briefing). A flight imported from the airgram (Section 15.10) or saved from the Route Planner’s Save as Flight button appears here automatically. Flights are stored on your account and sync across browsers (Section 16.3). Import / paste lets you bring in a flight exported from elsewhere via JSON.

Each flight remembers its own map-visibility preference. Click the eye icon next to a flight to hide it from the map without unloading it (you can still edit it from the panel). The choice is saved with the flight, so reloading the app keeps a flight you hid as hidden. A newly-created flight starts visible.

18.2 Aircraft profile

Pick an aircraft from the dropdown — the list is built from the presets and your custom aircraft as configured in Settings → Aircraft (Section 17.2). The selected aircraft populates fuel capacity, cruise TAS and burn rate plus the climb/descent perf needed for TOC/TOD math. To change the aircraft itself, head to Settings; to tweak perf only for the current flight, edit the numbers inline on the leg row — the badge will read “Edited for this flight” and Reset snaps back to the aircraft’s Settings values.

18.3 Flight rules

Pick VFR, IFR or leave it as —. The selection feeds the AI route brief (so it can recommend "needs IFR" / "VFR-only with caveats" against the actual weather), enables the matching reporting-point overlay (VFR Points / IFR Points), and turns on the Terminal Airspaces overlay automatically.

18.4 Legs and waypoints

Each flight is one or more legs; each leg is two or more waypoints. Add a leg with + Add leg. Each leg header carries ▲ / ▼ buttons to reorder the leg up or down (disabled at the ends) and a × to remove it. Reordering re-cascades the departure times down the chain (each leg keeps its turnaround gap after the previous leg’s new arrival); if a moved leg no longer starts where the previous one ends, a small ⚠ appears on its title so you can reconnect the route via its waypoints. Per-leg fields:

• Departure UTC — sets the departure instant (date + time, both UTC). Used for ETA, daylight check, TAF/METAR window selection, and the Route AI brief’s time framing. Type it directly, or use the quick buttons described in Section 18.4.3.
• Cruise altitude (ft / FL) — drives airgram cruise line, wind fetch level, and TOC/TOD math.
• Start fuel (gal) — per-leg starting fuel (defaults to aircraft fuel capacity for leg 1; subsequent legs continue from the previous leg’s landing fuel).
• Wind — manual or fetch forecast at cruise FL. Per-segment winds are stored when the forecast is fetched, so each segment’s ground-speed and ETE reflect the wind it actually flies through.

18.4.1 Adding waypoints

There are four ways to add a waypoint to a leg. They all target the currently-expanded leg in the accordion (or the last leg if none is expanded explicitly).

• Click anywhere on the map — whenever the Flight Planner editor panel is open, map clicks always drop a waypoint. The cursor turns into a crosshair to confirm the mode. Clicking lands on:
  • An airport marker → airport waypoint with the published ICAO and name.
  • A VFR / IFR reporting point → custom waypoint named after the published code.
  • Empty map (incl. inside a CTR / TMA / SUA / TSA polygon) → custom “WP n” waypoint at the click point. A background reverse-geocode tries to fill in a place name (Hamina, Lappeenranta…) within a second or two.
  • An existing waypoint marker on the route → the same point is appended again to the active leg (handy for stop-and-return profiles).
• + Waypoint button on the leg row — opens a search picker that resolves four kinds of input:
  • Airport by ICAO / IATA / name (e.g. EFHK, HEL, Helsinki).
  • VFR or IFR reporting point by code (e.g. DOPGA, ROBVU, NUMSU).
  • Free-form coordinates — the picker accepts decimals (64.711, 26.867 or 64.711,26.867), European decimal commas (64,711;26,867), hemisphere letters (60.32N 24.96E) and degrees-minutes-seconds with a variety of separators (60°10'N 24°58'E, 60 10 30 N 24 58 12 E). The candidate result is shown with a crosshair icon and the reverse-geocoded place name.
• Edit waypoints button on the leg row — opens a bulk-text FPL editor: a free-text field where each space-separated token resolves live. Recognised tokens chip green/blue/purple beneath the textarea; unknown tokens chip red and block Apply. Recognised airport / RP codes auto-uppercase as you type. Coordinate tokens show the reverse-geocoded place name below the coords. The Apply button replaces the leg’s waypoints with the new list — so this works equally well for editing an existing leg or composing a flight from scratch (e.g. paste in EFKI 64.3803,27.2994 MAINU EFHK and click Apply).
• Drag the route line on the map (editor open only) — grab the polyline anywhere between two waypoints and drag to drop a new waypoint at the release point. The temp marker and the route segments update live during the drag; a tooltip on the temp marker shows the live lat/lon, and if you release within ~1 nm of an airport the tooltip flips to "Release to snap to EFXX" and the new waypoint locks onto that airport instead.

18.4.2 Editing waypoints on the map

With the editor panel open you can also reshape an existing route directly on the map:

• Drag a numbered waypoint marker to move it. The route line bends with the drag in real time. Works on touch and on desktop. The waypoint tooltip refreshes with the live lat/lon throughout the drag; if you release within ~1 nm of an airport marker the wp snaps to that airport (ICAO + name preserved). Drag an airport waypoint off-snap and it demotes to a free-form custom waypoint at the drop coords — an amber "→ custom on drop" warning appears in the tooltip while you’re dragging so you know what will happen.
• Hover any waypoint marker for an info card: airports show ICAO + name + elevation + runway list + headline frequencies (TWR / ATIS / AFIS); custom waypoints show name + coords; VFR/IFR points show the published code and type. Hover info works whether the editor panel is open or closed.
• Click an airport waypoint to open that airport’s full popup (METAR / TAF / runways / frequencies / NOTAMs — same content the bare airport icon shows). Click any other waypoint type or click the route line to open the editor instead.
• The route polyline and numbered markers always render above every other overlay (airspaces, weather, observation icons) so a busy chart never hides your flight plan.

The waypoint list inside the leg accordion mirrors the on-map state:

• Airports show the ICAO and name (e.g. EFHK · Helsinki-Vantaa).
• VFR / IFR reporting points show the code and "VFR reporting point" / "IFR reporting point" label.
• Custom waypoints show the name (or the reverse-geocoded place) and the lat/lon to 4 decimals (~11 m precision).

18.4.3 Setting departure times

Each leg has its own departure time, and the legs chain together so the plan reads as one continuous timeline. Beside the date/time field is a row of quick buttons:

• Now (first leg) — sets the departure to the current time, rounded up to the next quarter-hour.
• At arrival (later legs) — anchors the leg to the previous leg’s computed arrival, so a multi-leg flight stays consistent end to end.
• +30 min / +1 h — the same anchor plus a turnaround gap, for a refuel or a break on the ground.

Setting one leg’s departure cascades through the legs after it: each downstream leg keeps its existing gap from the previous arrival, so a 30-minute turnaround stays 30 minutes when you shift an upstream departure. When you add a new leg, its departure is pre-filled to the previous leg’s arrival plus about 30 minutes, ready to adjust.

When you open a saved flight whose departure has already passed, the planner asks whether to re-anchor the whole plan to start now (keeping every turnaround gap) rather than silently rewriting your times — answer Cancel to keep the stored times and edit them yourself.

18.5 Leg summary

Each leg shows a live summary: departure date+time (weekday + UTC), distance, flight time, fuel used, fuel required (= fuel used + reserve), fuel-at-end with reserve OK/below badge, and arrival UTC. Numbers update as you edit waypoints, FL, IAS or wind.

18.6 Flight totals

Below the legs the panel shows flight totals: leg count, departure UTC of the first leg, total distance, total flight time, total fuel used, fuel required (used + reserve + taxi), and the final-leg arrival UTC. Same fuel-required math as the per-leg row, summed across all legs.

18.7 Per-leg tools — airgram, AI brief, print & export

Open a leg and its body shows, below the editable fields, a row of per-leg tools: two collapsible panes (Airgram, AI brief) and three action buttons (Print leg, FPL, Handling). When you’ve connected an autorouter account (Section 17.4), the leg also gains ✈ Auto route, Validate route and a flight-plan filing control — covered in Section 18.12.

The two collapsible panes:

• ▶ Airgram renders the same vertical cross-section as the standalone airgram tool, with the leg’s waypoints, cruise FL and departure UTC pre-loaded. The chart updates whenever you edit the leg.
• ▶ AI brief streams a route briefing from Claude. The brief sees the leg’s METAR/TAF for every airport waypoint, structured TAF periods with absolute UTC timestamps (no DDHH decoding), per-leg SUA list within a 30 nm corridor (multi-sample classification across the flight window), SIGMETs / national CAP warnings sampled along the track, LLF, the airgram, and the full aircraft perf. The output is exactly two blocks: a colour-coded dashboard (WIND / CEIL / ICING / TURB / CONV / NOTAM as Green / Yellow / Red) plus a hazards table.

⎙ Print leg

The Print leg button opens the same printable briefing as the whole-flight one (Section 18.8) but scoped to that single leg — the cover/summary, navlog, airgram, AI brief, that leg’s airports and a route map covering just this leg. The leg keeps its real number in the flight (so leg 3 still prints as “Leg 3”) and the PDF filename suggestion is the leg’s own label. Use it when you only need a fresh briefing for one leg of a multi-leg trip rather than re-printing the whole flight.

PLOG & Log flight

Two leg buttons tie the plan to what you actually fly. PLOG opens the live moving map & PLOG (Section 21) for that leg — planned vs. actual, in flight. Log flight creates the matching logbook entry (Section 22), or, once a flight is already logged for the leg, the button becomes ✓ Edit log and opens the existing entry instead.

⤓ Export to ForeFlight (.fpl)

The FPL button (to the right of Print leg) exports the leg as a Garmin .fpl flight plan — the standard route format that ForeFlight (and Garmin avionics) import directly. It downloads one file per leg, named DEP-DEST.fpl, so a multi-leg trip becomes several ForeFlight routes. Waypoints map as follows: airports carry their ICAO; named fixes and navaids carry their identifier; other points export as user waypoints with their coordinates. The leg’s alternate is not included (it’s a divert field, not a route point).

To import on an iPad / iPhone: open the downloaded .fpl (from Files, an email attachment, or AirDrop) and choose Open in ForeFlight. The route loads on the Maps view, ready to drop into a flight.

✉ Announcement

The Announcement button opens a pre-filled flight-announcement email in your mail app for the leg’s destination. The recipient is left blank (address it to the field’s handling agent yourself); the subject and body are filled from the leg and the trip’s aircraft:

• Subject: Flight announcement: {registration} - {arrival date} {arrival time}Z.
• Body: destination, aircraft registration, type and MTOW, flight type, and a Crew X / PAX X placeholder line, followed by two blocks and the Services requested block.
• Arrival: From {origin} and ETA {date} {time}Z — this leg into the destination.
• Departure: To {next destination} and ETD {date} {time}Z — the next leg out of this same field. On the final leg there is no onward departure, so the whole Departure block is hidden.
• Services requested: always AC parking. Fuel: when the next leg starts with more fuel than this leg lands with — i.e. you refuelled here — a Fuel {grade} line is added. The grade is Jet-A1 or AVGAS per the aircraft’s Fuel type (Section 17.2). No refuelling between legs → no fuel line.

The registration and MTOW come from the aircraft profile — set them in Settings › Aircraft (Section 17.2). All times are UTC.

18.8 Print briefing

The Print briefing button (in the flights library row, the panel toolbar, and the Route Planner) renders a complete printable briefing. The dialog opens in landscape orientation by default and the content is auto-scaled to 90 % so the wide navlog table + side fuel panel fit comfortably on each sheet. The browser’s "Save as PDF" filename suggestion is the flight’s own name ({flight} — briefing.pdf) instead of the host page’s tab title.

The page order is fixed and each section is forced onto its own sheet so the print is easy to flick through on a kneeboard:

1. Page 1 — Flight summary cover. Trip name, generation timestamp, full route line (chained airports), then a 2-column grid: legs / departure / distance / flight time / fuel used / fuel required (with taxi + reserve breakdown) / final ETA / airport count. An Aircraft sub-block lists the assumptions used for the math — cruise TAS / burn, fuel capacity, reserve (min + gal), taxi (min + gal), climb perf, descent perf — so the briefing is self-contained.
2. One page per leg. Navlog-style header (route, ETD/ETA, distance, time, winds, fuel), a side FUEL + INFO column, and a VFR-simplified navlog table: Waypoint / Alt / Wind / Hdg / GS / Dist / Fuel rem / ETE / ETA. TOC / TOD pseudo-rows appear inline. The airgram cross-section for the leg sits at the bottom of the page, ~10 % taller than before so the climb / cruise / descent bands have more vertical resolution.
3. One page per leg — AI route brief. The streamed AI briefing for each leg lands on its own sheet so it doesn’t crowd the navlog.
4. Airports section. An "Airports" heading followed by the first airport block on the same sheet, then each subsequent airport on its own page. Per airport: ICAO + name header, Info + Weather columns (METAR / TAF parsed table / hourly / LLF / runways / frequencies / refined hours / tower schedule).
5. Route map. Clean SVG of the whole flight with active R/D/P / TSA polygons drawn in (corridor-distance filter: only items within ~30 nm of the route, classified across the full flight window, not just print time). Items where the planned cruise penetrates an SUA’s vertical band get a red ⚠ marker on the map polygon.
6. Active Special Use Airspaces. Dedicated page with the table of relevant SUAs (the ones flagged on the map above): type, code, location, altitude band, status, time-of-day windows, source. A banner above the table summarises the count and the time window evaluated. NOTAM details (Q-code, F/G limits, full E-line) follow underneath.
7. Footer. PIC + date/time signature lines and a brief disclaimer reminding the pilot to verify against official sources.

18.9 Flight summary

The ☰ Summary button in the panel toolbar opens a quick fixed-width popup summarising the whole flight — one block per leg with departures, arrivals and refuels, each shown in both Zulu and local airport time. Local time is resolved from the airport’s ICAO region (DST-correct for the planned date; a day-rollover is flagged, e.g. 0230L+1), with a longitude-based fallback for airports outside the covered regions. Each leg lists distance, ETE and the start → end fuel; between legs a GROUND line shows the turnaround time and, when the next leg starts with more fuel than this one lands with, a refuel +N gal line (grade per the aircraft’s fuel type). A TOTALS line follows (distance, flying time, leg count, refuels), and an AIRPORTS list closes it out — every airport on the flight (plus alternates) as code · name · country. Copy puts the text on the clipboard for a logbook or email; Close or Esc dismisses it. All times shown with Z are UTC and L are local.

18.10 Persistence

Every change is written to your account in real time (with a per-browser cache for instant load). Saved flights and aircraft profiles survive reloads, new app versions, and follow you to any browser where you sign in — see Section 16.3 for the full sync list. The library’s JSON paste / file controls are still there for offline export when you want a local backup.

Reopening a flight whose departure has already passed prompts you to re-anchor it to start now (Section 18.4.3); your stored times are never rewritten without that confirmation.

18.11 Actual flown track vs the plan

After a flight you can attach the actual flown track (from Flightradar24) to a leg and compare it against the plan — deviation from the planned route, actual block / airborne times and an altitude profile, with the real track overlaid on the map. Each leg carries an ✈ Actual chip to attach or toggle it. The full workflow is covered in Section 19, The Flown Track Tool.

18.12 Auto route & flight-plan filing

With an autorouter account connected (Section 17.4), each leg can be routed and filed under your own account. You can file both IFR and VFR flight plans — the channel follows the leg’s flight rules (Section 18.3). Until you connect, the buttons still appear but prompt you to connect first.

✈ Auto route (IFR)

Finds and validates an IFR route for the leg using your autorouter account and the leg’s aircraft. It returns a valid routing — with SID/STAR and airway structure — and writes it onto the leg: the route string, the detailed waypoints and the cruise level. The map then draws the procedural points. Re-running re-routes the leg. If no matching aircraft is found in your autorouter fleet, you’re guided to create / match one. (Auto route applies to IFR only; for VFR you enter the route yourself.)

Validate route (IFR)

Checks the leg’s current IFR route against Eurocontrol (IFPS / CFMU) validation without re-routing — useful after hand-editing waypoints. Any errors are listed so you can fix the route before filing.

File a flight plan

Each leg shows a flight-plan control labelled with its current status (e.g. File, then Filed). Click it — or the leg’s FPL tool — to open the ICAO flight-plan view. How a filed plan is transmitted depends on the flight rules (field 8):

• IFR — validated and filed through IFPS (Eurocontrol); once accepted the plan carries an IFPLID.
• VFR — sent over AFTN to the relevant ATS reporting offices (a pure VFR plan is not processed by IFPS); it’s tagged AFTN rather than given an IFPLID.

The flight-plan form

The view is the full ICAO flight plan, pre-filled from the leg and the aircraft profile. You can edit any field; an Assembled FPL preview at the bottom shows the exact message that will be sent and updates live as you type. The boxes follow the ICAO item numbers:

Item 19 C/ (pilot-in-command), and a contact phone in RMK/, pre-fill from your captain profile (Settings → Captain). Three buttons sit above the filing bar: Validate (IFPS) runs the route / format check (for a pure VFR plan it notes that IFPS isn’t applicable), Copy FPL copies the assembled message, and Reset to computed discards your edits and rebuilds the plan from the leg.

The stages

The filing bar at the bottom of the view offers only the actions valid for the current stage. You confirm before anything is transmitted — the prompt names the channel (IFPS or AFTN).

1. Not filed (draft) — File flight plan.
2. Filing… — sent and being processed; the status refreshes automatically (or use Refresh status). You can still Cancel filing.
3. Filed — accepted (IFR plans now carry an IFPLID; VFR plans show an AFTN tag). From here: Mark departed, Change departure time, Re-file (if the plan changed), Refresh status, or Cancel flight plan.
4. Airborne → Arrived — after departure you can Mark arrived; arrived / closed plans are read-only.
5. Rejected — fix the flagged problem and Edit & re-file. Cancelled — you can File a new flight plan.

The leg header and the FPL tool both carry a colour-coded status chip mirroring this state. Every filed plan is also reachable from Settings → Autorouter → Manage filed flight plans.

Editing & re-filing

Edits you make in the form are stored on the flight (so they survive reload and sync) and flow into both the assembled message and Validate route. When a plan is already filed, the form keeps the two versions clear:

• The form shows the current (to-be-filed) values, and a banner reports how many fields changed since filing.
• Each changed field gets a clickable ↵ filed: X chip — click it to revert that one field to the value actually on file.
• A changed flag also shows on the leg / status chip. Re-file replaces the filed plan with the current one, re-evaluating the channel from field 8.
• Change departure time reschedules a filed plan (a quick ±15 min nudge or a new EOBT) without rebuilding the whole plan.
• Cancel withdraws the filed plan; a cancelled leg can then be filed afresh.

19. The Flown Track Tool (✈)

The Flown Track tool shows the route you actually flew — pulled from Flightradar24 — so you can review the flight and compare it against your plan. Open it with the ✈ button at the bottom of the top-left control stack. (To record a flight live from your own GPS instead of pulling it afterwards, use the in-flight moving map, Section 21.)

What you need: the lookup is keyed on your aircraft’s registration, so add your aircraft (with its registration) in Settings → Aircraft first. The flight must have been seen by Flightradar24’s ADS-B network.

19.1 Finding a flight

Pick an aircraft from the dropdown; the tool automatically lists that registration’s flights from the last 14 days, newest first (route, date, off/on times and type). Click one to load its track. Each lookup uses your Flightradar24 quota, so a flight you’ve already opened is cached — reopening it costs nothing.

19.2 The track on the map

• Coloured by altitude — the route is drawn in altitude bands, with a legend from ground to 7 500 ft+.
• Scrub for detail — hover or drag along the track or the profile chart (works with a finger on touch screens) to read time, altitude, groundspeed, vertical speed, heading and flight phase at any point.
• Play — replays the flight, running a marker along the track.

19.3 Flight detail

Selecting a flight opens a detail card with:

• Stats — airborne time, distance flown, max altitude, max and average groundspeed, max climb / descent.
• Block & flight times (OOOI) — off-block, takeoff, touchdown and on-block, plus block, airborne and taxi times. Takeoff / touchdown come from Flightradar24 when reported; off-block / on-block are inferred from ground movement in the track. Inferred values are marked with a ~.
• Altitude & groundspeed profile against time, with a flight-phase strip (ground / climb / cruise / descent).

19.4 Comparing with your plan

You can attach a flown flight to a leg in the Flight Planner and keep it with the trip. There are two ways in:

Once attached, the leg’s chip turns to ✓ Actual and the leg gains a comparison block: actual block / airborne times, distance flown, max altitude / speed, and how far the track strayed from the planned route (max and RMS cross-track distance). The profile draws your planned cruise altitude for reference.

• Show on map — overlays the colour-coded actual track on top of the planned route.
• Saved with the trip — the track is stored on the leg (compressed), so it travels with export / import and sync, and is available later offline without another Flightradar24 lookup.
• Re-attach / Remove — replace the attached flight or clear it.

19.5 Export

The GPX button downloads the flown track as a GPX file (lat / lon, altitude and timestamps) for use in other tools.

19.6 Notes & limits

• Flightradar24 serves roughly the last 30 days of history but limits each query to a 14-day window, so the tool offers the last 14 days.
• ADS-B coverage on the ground is patchy for light aircraft — if taxi movement wasn’t captured, off-block / on-block times can’t be inferred and show as “—”.
• Groundspeed (not true airspeed) is shown; there is no wind / TAS estimate.
• This is for review and situational awareness, not a certified flight record.

20. Print Briefing (⎙)

The printer-icon button in the bottom-left corner of the map opens a print-ready briefing of the current view. The briefing opens in its own window for review; click Print there (or Ctrl/Cmd+P) to print to paper or “Save as PDF” for a paperless kneeboard reference. The pages are laid out in landscape — some browsers (notably Safari) don’t switch orientation automatically, so pick Landscape in the system print dialog if needed.

If you have saved presets (Section 20.3), the print button opens a small menu: Current view prints exactly what’s on the map now, or pick a preset to print its saved layer set in one click. With no presets, it prints the current view directly.

20.1 What gets printed

• The map(s) — one chart per page. A clean snapshot framed exactly to your current view, with the same basemap, overlays, airport labels and routes you can see on screen. All controls, panels and buttons are hidden.
  • Because each kind of overlay obscures the others, layers are split into up to three per-purpose maps, each on its own landscape page, in this order: “Weather” (forecast + radar / satellite), “Low Level Forecast” (LLF polygons), and “Airspace & info” (TMA / CTR, SUA, points) — the airspace map last, where it’s easy to find for cross-checking the navlog.
  • If only one of those groups is active (or none), you get a single combined map.
  • When a preset has the SWC option on (Section 20.3), a Significant Weather Chart page is inserted just before the Airspace map.
• Appendix pages — everything that normally hides behind hover or popup, auto-collected from the map state at print time:
  • Active Special Use Airspaces intersecting the view — R / D / P / TSA / TRA areas with the NOTAM IDs, time windows and altitude bands that activate them. Only operationally active variants are listed (active now, activating later today, or a currently in-force triggered AIP SUP). Inactive or future-day areas are skipped so the appendix stays short and decision-relevant.
  • Terminal airspaces (TMA / CTR) intersecting the view, with their controlling unit and frequencies.
  • Active SIGMETs covering the view.
  • Aerodromes visible on the map — ICAO, name, METAR category and current observation in compact form.

20.2 What gets captured from your view

The print map is rendered in a hidden iframe so it doesn’t disturb your live session. The iframe receives the full view state via URL parameters: bounds (so the printed map matches the on-screen frame exactly), basemap choice, the list of enabled weather and observation overlays, the currently selected altitude key, the time-bar offset, and the label-visibility toggles. The browser’s print stylesheet then lays each map (Section 20.1) on its own landscape page, with every appendix heading starting on a fresh page so the packet reads cleanly. The aerodrome table also fills in unofficial weather (EFLA Flyk, EFNU CloudATIS, nearest IL AWS — Section 6.6) for fields with no official METAR, before falling back to the Open-Meteo model.

20.3 Presets

A preset is a named, saved set of map layers (plus an optional SWC chart for briefings). It serves two purposes: apply it to the live map in one tap to switch between viewpoints (convection, icing, a VFR layout…), or print it as a briefing in one click without changing the map you’re looking at. Presets sync across every device you sign in on. They require sign-in.

The quickest way to use them is the layers button on the main screen — the stacked-squares icon in the top-left, just under the funnel filter. It opens a small panel that lists your presets: tap one to apply it to the map, tap the printer (⎙) on a row to print it as a briefing, or tap + Save current view to capture the layers currently on the map as a new preset. Manage in Settings opens the full editor, where you can also attach an SWC chart for briefings.

Creating & editing presets

Beyond the main-screen Save current view, the full editor is at Settings › Presets. Two ways to start:

• + New preset — opens an empty editor.
• + From current map layers — pre-fills the editor with whatever layers are on the map right now, ready to fine-tune.

In the editor you pick exactly what the print should contain — you don’t need to turn anything on the live map first:

• Layers — tick boxes grouped into Airspaces & info, Weather, Radar / Satellite and Low Level Forecast.
• Altitude / level — the level the altitude-aware weather layers render at (Total, Low / Mid / High, or a specific FL).
• Forecast time — print “now” or a forecast offset (+1 / +3 / +6 / +12 / +24 h).
• Include SWC chart — adds a Significant Weather Chart page (choose Finland / Nordic / Europe) just before the airspace map.

Each saved preset shows on the list with a layer count and a short summary; Edit reopens the editor, Delete removes it.

Printing a preset

Click the bottom-left print button and pick the preset from the menu. The app prints its saved layers, altitude, time and SWC choice straight away — the live map is left exactly as it was. Airspace tables in the appendix are fetched in the background for the current view, so they appear even if those overlays aren’t switched on. (Choose Current view in the same menu to print what’s actually on the map instead.)

21. In-Flight Moving Map & Navlog (☉)

Once you’ve planned a flight you can fly it with a live moving map: your own-ship position on the chart, leg-by-leg navigation, a running PLOG (planned vs. actual) and automatic OOOI timing that feeds straight into your logbook. It’s the ☉ Show my location button at the bottom of the top-left control stack.

What you need: you must be signed in, and your browser must allow location access. Tracking keeps the screen awake and is designed to keep working offline — see Section 21.6.

21.1 Starting and stopping

Tap ☉ to start tracking; tap it again to stop. On stop, if you’ve recorded a track against a leg you’re asked whether to save it (Section 21.5). You can also jump straight into the moving map for a specific leg from the Flight Planner — see the PLOG button in Section 18.

21.2 Own-ship HUD & leg navigation

• Own-ship — your position, track, ground speed and altitude are drawn on the map and follow you as you fly.
• Pick a leg — tap the HUD to choose which flight-plan leg to navigate against. The map then shows the next waypoint with distance and bearing, advancing through the leg as you pass each point.
• Follow mode — the map keeps you centred; pan away to inspect, and it stays where you left it until you re-enable follow.

21.3 OOOI times

While you track, the app stamps the four OOOI events — off-block, take-off, touchdown and on-block — from your movement, and derives block, airborne and taxi times. These become the times on the logbook entry, so a saved flight already has correct block and flight time without any typing. You can correct any of them later in the logbook editor.

21.4 The PLOG (planned vs. actual)

The PLOG panel compares the leg you’re flying against the plan, in real time.

• Planned vs. actual — per-waypoint ETAs and fuel for the selected leg, against what you’re actually achieving.
• Seeded from the plan — estimates start from the planned departure time and fuel burn, then update as you fly.
• Tap to edit — tap any time to adjust it on the fly; a row can be skipped if you overfly a point.
• Rule changes — if you switch VFR ↔ IFR in flight, the change is logged so the air time can be split correctly in the logbook.
• Offline — the PLOG works with no connection.

21.5 Recording, autosave & saving to a leg

• Recorded as you fly — the GPS track is captured and autosaved continuously, so an interrupted session (crash, reload, dead battery) can be recovered on the next load.
• Save to the leg — when you stop after landing, a short post-flight summary captures take-offs / landings (day & night), fuel remaining, anti-ice and oil, and a VFR/IFR confirmation, then writes the flight to the leg.
• Into the logbook — the saved track, its OOOI times and the post-flight details appear as a logbook entry automatically.

21.6 Offline

Before departure, warm the route’s basemap tiles (see Section 23, Offline Mode) so the moving map stays complete with no signal. GPS itself needs no connection, so own-ship, leg navigation and the PLOG keep working in the air; the saved track syncs once you’re back online.

22. Logbook

A built-in pilot logbook that fills itself from the flights you fly — EASA-style — and is fully editable. Reach it from the Flights library on the Logbook tab. Like the moving map, the logbook is available to signed-in users.

22.1 Where entries come from

• Automatically — every flight you save an actual track to becomes an entry: from the in-flight recorder (Section 21) or the Flown Track tool (Section 19).
• From a plan leg — the Flight Planner’s Log flight action on a leg creates (or opens) the matching logbook entry.
• By hand — + Add flight manually for a flight with no track.

22.2 EASA basis

The logbook follows EASA conventions so it can stand in for a paper logbook:

• Flight time = block time (off-block to on-block), per FCL.010.
• Night is computed on the SERA definition — the sun 6° below the horizon (civil twilight) — for the actual date and position.
• Columns follow AMC1 FCL.050: single- / multi-engine, multi-pilot, PIC / dual / instructor function time, day & night take-offs and landings, IFR / VFR and night time. Class (SE/ME) and function are derived from the aircraft and the flight.

22.3 Editing & summaries

Tap any row to open the inline editor — adjust times, function, landings, fuel or remarks; times cross-fill (OUT↔OFF, IN↔ON) so block and airborne stay consistent. Summary cards at the top total your time, block, IFR / VFR, night, PIC and SE / ME hours, plus a rolling 90-day landing count.

22.4 Filters & deleting

• Filters — narrow the list by date range (from / to or last x days), PIC or aircraft.
• Delete — remove a single entry from its editor, or bulk-delete the whole shown (filtered) list with the Delete button below it; a confirmation spells out whether it’s the filtered subset or every flight.

22.5 Export & import

• Export (▾ menu) — CSV, Excel (.xlsx, with durations formatted as h:mm that sum correctly) or ForeFlight logbook-import format. Exports include only the rows currently shown by your filters.
• Import — load an existing logbook from an Excel (.xlsx) file. A preview pairs each row against your existing entries and flags likely duplicates, so you choose per row whether to add, update or skip.

22.6 Print an EASA page

The Print button renders a printable EASA logbook page — the standard column layout with running and page totals and signature columns — covering the rows currently shown. It opens in its own window; use “Save as PDF” for a paperless copy or print it for a physical logbook.

23. Offline Mode

The app supports a full offline experience: pre-fetch weather, NOTAMs, AIP, airspaces and flight-planning data while you have network, then operate normally without one — in the cockpit, on a remote field, on a long ferry where mobile data is unreliable. Snapshot data is served from the browser’s IndexedDB so the same airport popup, briefing print and Flight Planner work as if you were online, just with cached values.

23.1 What works offline

With offline mode active the app serves the following from the local snapshot:

• METAR, TAF and NOTAMs for every airport in the countries you selected at prepare time.
• AIP per-airport summary — hours, frequencies, runway and approach info.
• Airspaces — R / D / P, CTR / TMA, terminal areas, Flyk supplements.
• VFR / IFR reporting points and ACC sectors.
• Hourly Open-Meteo wind & weather at each saved-flight waypoint, sampled at that waypoint’s ETA.
• Per-leg airgram cross-sections for every saved flight.
• Area NOTAMs per FIR for the countries you selected.
• The full Flight Planner UI and saved flight library.
• The briefing Print (using snapshot data).
• Map basemap tiles you have already viewed (cached by the service worker on demand), plus the embedded Help (?) modal and this User Manual.

23.2 What does not work offline

The following are network-only and will be unavailable until you switch offline mode off:

• Live forecast layers (winds, clouds, icing, turbulence, precipitation, fog, MSL pressure, SIGMETs) on the map.
• Radar and satellite imagery.
• Significant Weather Charts (SWC).
• LLF (Nordic Low Level Forecast) — live FMI feed.
• Click-anywhere weather popup at coordinates outside your saved-flight waypoints.
• The “Draw a line on the map → airgram” tool (it always fetches fresh Open-Meteo).
• AI summaries (NOTAM AI, route briefing AI, weather summary).
• Feedback form.
• Account sync — pushes to the server are queued and replayed when you Resync.

The right-side weather, radar, LLF and SWC menus, the bottom-right DA62 panel and the “Draw a line → airgram” button are hidden automatically while offline mode is on, so you don’t accidentally trigger something that cannot complete. The map-overlay (globe) menu, Flight Planner, Legend and Help stay visible because they all work with cached data.

23.3 Preparing the snapshot

1. Open the avatar menu (top right) and choose ✨ Prepare for offline.
2. Country selection. Pick the countries you need. Defaults come from your saved flights — a Tampere → Tallinn flight pre-checks Finland and Estonia. Pre-checked countries sort to the top of the list; the rest are alphabetical. A search box trims the long tail. Each row shows the number of airports in that country.
3. Press Prepare snapshot.
4. A progress modal walks through each phase: METAR, TAF, NOTAMs, Saved flights (per-waypoint hourly forecast), Airspaces (R / D / P / CTR / TMA), AIP per airport, Airgram per leg, VFR / IFR points + ACC sectors, Area NOTAMs (by FIR). A blue status line at the top reports the active sub-step (“Fetching METAR batch 3 / 17”). Active rows are highlighted, finished rows get a green check.
5. Typical durations: Finland-only (~100 airports) finishes in 30–60 seconds; Nordic in 1–2 minutes; a European-wide selection can take 5 minutes or more depending on connection speed.
6. Cancel is always available. The partial snapshot stays in IndexedDB; re-running Prepare picks up where you left off (and re-fetches the running phase).

23.4 Going offline / online

When the snapshot is ready, press Go offline now. A blue 📱 Offline mode banner pins to the top of the viewport showing the snapshot timestamp.

To go back online:

• Click anywhere on the banner area (not the Resync button) → the Manage view opens → press Go back online.
• Or open the avatar menu → ✓ Offline mode on → Go back online.

The banner disappears, the network-only menus reappear, and live data resumes.

23.5 Snapshot freshness and refresh

Weather data ages quickly — a 12-hour-old METAR or TAF is less useful than a fresh one. The banner shows the snapshot timestamp (e.g. “Snapshot 14:30Z”) so you can tell at a glance how stale the data is.

To refresh without leaving offline mode:

• Click the banner → Manage view → Refresh snapshot. This re-runs the prefetch with the same country selection.
• To change the country list, switch offline mode off first — the avatar menu then offers Prepare for offline with the full country picker.

23.6 Edits made while offline

Saving a flight, editing waypoints, updating aircraft profiles or changing settings while offline mode is on all save locally in your browser immediately. They cannot reach the server (you have no network), so they go into a small sync queue.

The banner shows a pending-sync count when there’s anything queued:

📱 Offline mode · Snapshot 14:30Z · 3 pending sync   [ Resync ]

Press Resync when you’re back on a working network. A toast reports the outcome:

• ✓ 3 changes synced — all queued writes succeeded; the queue is empty.
• ⚠ 2 sync attempts failed with a one-line reason (sign-in needed, network unreachable, server returned 404, etc.); the entries stay queued for next time.
• ✓ 1 synced, 2 still queued — partial success; the queue keeps the rest.

Resync only drains the queue. It does not turn offline mode off — the snapshot data keeps serving while pushes flush in the background. Use Go back online for the actual mode switch.

23.7 Storage usage

The snapshot lives in your browser’s IndexedDB under airports-offline. Rough sizes:

Browser quotas for IndexedDB are typically 500 MB–2 GB. To wipe the snapshot completely, use your browser’s DevTools (Application → IndexedDB → airports-offline → Delete database) or open the avatar menu and re-Prepare with no countries selected.

24. Pre-Flight Workflow Tips

The workflows below walk through the app the way the tool is meant to be used — from the synoptic big picture, down to the route, down to the cruise level, then back out to airspace and observations. Times are rough budgets, not deadlines: a clear-blue-sky day might end at step 2.

25. Reading Wind Barbs

Wind barbs follow standard meteorological conventions. The staff points into the wind direction — a barb pointing north means wind from the south. Speed is encoded as additive flags on the staff:

Wind speed is rounded to the nearest 5 knots. Barbs are additive: a pennant + two full barbs + one half barb = 75 kt.

26. Reference Tables

26.1 Flight-Category Cheat Sheet

26.2 Common METAR Weather Codes

Modifiers stack: +SHRA = heavy rain shower; -FZDZ = light freezing drizzle; VCFG = fog in vicinity.

26.3 Cloud Cover

26.4 Units

27. Data Sources & Disclaimer

27.1 Where Each Layer's Data Comes From

27.2 Disclaimer

Prepare Flights — User Manual
For pilots, by pilots · Updated June 2026