FAQ
What does this page do?
It helps flight crews quickly check live METAR/TAF for any ICAO airports and
rank potential alternates around a destination by best weather first (visibility, wind),
followed by distance. It is a training aid only
and must never replace official company tools or operational judgement.
How do I use it?
Enter Destination ICAO + ETA at Destination + Radius (NM) → Find Alternates.
(Optional) Toggle filters: Require ILS, CPNY Base, CPNY Destination, runway length or rank by desired alternate.
Where does the weather data come from?
The weather information comes from trusted aviation sources and is updated live each time you request it.
Can I use this tool as a primary reference?
No. This tool is intended solely as a supplementary planning aid. Always rely on official meteorological sources and company or regulatory data for operational decision-making.
Why do I sometimes see METAR but no TAF (or vice versa)?
Sometimes one of the reports may be temporarily unavailable. The status line will mention what was loaded and if any report was missing.
How are alternates ranked?
Alternates are prioritized by best visibility first, then wind conditions, and finally shortest distance from your destination.
What do the distance and bearing mean?
Distance is the great-circle distance (in NM) from the destination. Bearing is the initial course from the destination to that alternate.
What does “Require ILS” do?
It limits the list to airports equipped with an ILS approach.
What are the “CPNY Base” and “CPNY Destination” filters?
These filters allow you to display only airports used as CPNY crew bases or CPNY destinations, if such data is available.
What runway length is shown?
Runway length is displayed in meters (rounded). If no data is available, you’ll see a dash (—). Please note that the database may not always be fully up to date, and actual runway lengths can differ. Always confirm the latest information through official charts or company documentation.
Why are only about 10 alternates shown?
To keep things fast and clear, only the top 10 alternates are displayed after ranking by weather and distance.
The wind line says “wind n/a”. Why?
If the wind information couldn’t be extracted from the report, you’ll see “wind n/a”. You can still read the full data in the raw text.
How current is the data?
Each lookup retrieves fresh data every time. Check the timestamp displayed next to the ICAO code for confirmation.
How are visibility colors decided ?
We apply quick-scan colors that match the dark Ops theme:
- Green: ≥ 5 km
- Orange: 3 km–<5 km
- Red: 550 m–<3 km
- Magenta (below CAT I): < 550 m
Values are computed from the best visibility reported (converted to meters when needed).
How are wind colors decided ?
We color the wind speed (kt) for rapid threat assessment:
- Green: < 15 kt
- Yellow: 15–<25 kt
- Red: ≥ 25 kt
The speed is parsed from the wind group, gust are not accounted for (e.g.,
210/18kt).
How are ceiling colors decided ?
We color the ceiling for rapid threat assessment:
- Green: > 1000
- Orange: ≥ 400 - 1000
- Red: ≥ 200 - 400
- Magenta: below 200
The speed is parsed from the wind group, gust are not accounted for (e.g.,
210/18kt).
What is the “Select ETA at destination” banner above the wheels?
It mirrors your chosen date/hour and shows a bold UTC time plus a relative label (e.g., “in 12h”). This same ETA is used to
highlight the relevant TAF segment and to evaluate CB presence at that time.
When does the red “CB” badge appear?
When the parsed TAF indicates cumulonimbus (CB) within the highlighted ETA segment or time group. It’s a heads-up to review
convective risks at that time. Always verify against the full TAF and official sources.
How is the TAF “highlighted at ETA”?
The app parses validity groups (FM/PROB/TEMPO/BECMG etc.) and highlights the block(s) that cover your selected ETA,
so your eyes land on the most relevant forecast lines first.
What does “Rank based on your selected alternate airports.” do?
You can enter up to six ICAOs to restrict alternates to known desired airports. When this is enabled:
- CPNY Base/Destination filters are turned off (to avoid overlap).
- Radius is disabled and shown as informational text.
- Any entered ICAO that doesn’t appear in results is marked red (non-blocking).
Why do I see a Destination card above the alternates?
The tool always displays a dedicated destination weather card at the top. It uses the same chips and color logic
as the alternates (visibility, wind, ceiling, CB flag), plus an “ETA at DESTINATION” banner and the full METAR/TAF.
It helps you compare alternate airports against actual destination conditions.
What does the “OUTSIDE OF VALID TAF PERIOD” badge mean?
This appears when your selected ETA falls outside the valid TAF window for that aerodrome.
The TAF is still shown for reference, but it should be treated with caution. Always verify using official sources.
What is the “Alt fuel (approx)” line under each alternate?
It is a very rough, rounded estimate of alternate fuel and time.
It is for training and illustration only and must never be used for operational fuel planning.
What is the little “Quick tour” bubble that appears after the disclaimer?
After accepting the disclaimer, a small guided tour appears to highlight the main inputs and controls.
You may click Skip to dismiss it. A long-press on Skip hides the tour for 30 days on that device.
Why do I see messages like “Already searching…” or “Please wait a few seconds”?
The tool includes simple protection against rapid repeated searches, and the backend also rate-limits requests.
If you click Find Alternates too quickly, you may briefly see a cooldown message. Wait a few seconds and try again.
Why do I see a disclaimer each time?
The disclaimer is intentionally shown on every load. This tool is for reference and training only, not an operational tool
Mobile support
The layout adapts automatically for small screens — filters become full-width toggles, and buttons stack for easier touch navigation.
Browser support
Works best with any modern browser (Chrome, Edge, Firefox, Safari).
Troubleshooting
“Destination not found.” Check the ICAO code or use a larger search radius.
“No candidates in radius.” Increase the radius or remove filters like ILS/CPNY.
“Error loading data.” Retry after a few seconds — the source may be busy.
Privacy
No sign-in, no tracking — everything runs locally in your browser. Your inputs aren’t stored anywhere.
Database coverage
For performance and clarity, the internal airport database excludes any airfield with a runway shorter than 1500 meters.
Currently, it includes only airports starting with the following prefixes:
Lxxx, Exxx, GCxx, and GMxx.
Additional regions may be added in future updates.
Who built this?
Developed by an airline captain with 10,000 flight hours and nearly a decade of command experience.