this App is a work in progress.. please provide feedback, suggestions, issues
the Source code is published for here review, you are welcome to "fork" and modidy to build your own.
https://github.com/RuneKyndal/tanking/
Installation link:
https://runekyndal.github.io/tanking/index.html
The app is a Progressive Web App (PWA). It must be installed to work offline — a browser bookmark alone will not cache the files. It WILL fail to load if offline.
Poor connection at startup? If the app stalls on launch while on a weak signal, enable Airplane Mode to force it to load from the offline cache. Once loaded, disable Airplane Mode if you need GPS.
The app checks for updates automatically at startup. To force an immediate update, use Update App in the Setup page.
Most inputs — aircraft type, gross weights, burn rate, ground speed target, and distance to fuel — are saved automatically and restored next time you open the app.
Tap ⚙ SETUP from either the calculator page or the flight page to open the Setup page. Use the ← BACK button to return to wherever you came from.
The Setup page is organised into sections:
| Button | What it does |
|---|---|
| ⓘ Manual | Opens this manual. |
| ↻ Update App | Clears the offline cache and downloads the latest version from the server. Your weights, settings, and flight log are not affected — only app files are updated. |
| Button | What it does |
|---|---|
| 🌙 Dark Mode | Toggles dark/light scheme. Preference is saved. Button label reflects current state. |
| ☀ Keep Awake | Prevents screen auto-lock. Label shows Awake (ON) when active. Not supported on all browsers. |
| Button | What it does |
|---|---|
| 📍 GPS Permission | Attempts to trigger or repair the location permission dialog. If the permission was previously denied, this will show instructions to fix it in your device settings. See the GPS section for full details. |
The flight page displays two endurance figures simultaneously. They serve different purposes and are both required on screen.
Fuel on board divided by burn rate — no reserve deducted. This is the number passed to flight services for SAR purposes.
Usable endurance to the 500 lb reserve. This is the planning number — transit, tasking, and bingo calculations are all based on this figure.
The FUEL CALC button in the flight page top bar shows or hides the detailed planning section — Operational Endurance, Fuel Plan GS, Range, and Bingo-in countdown.
FUEL CALC green = planning section visible. Dark = collapsed, leaving fuel load slider, Total Endurance, and the always-visible Bingo-in summary. Useful when screen real estate is at a premium. Setting is saved.
Bingo fuel is the quantity at which you must turn for fuel immediately — calculated so you can cover the Distance to Fuel at the selected ground speed and burn rate, and still land with 500 lb remaining.
| Colour | Condition |
|---|---|
| YELLOW | Within 15 minutes of bingo fuel — advisory. Likely your last drop before heading for fuel. |
| RED | Bingo fuel reached — turn back now to land with 500 lb. |
| Colour | Condition |
|---|---|
| YELLOW | Fuel remaining at or below 800 lb — advisory. Time to plan for fuel. |
| RED | Fuel remaining at or below 500 lb — reserve reached. Land now. |
Tap GPS OFF on the flight page to start the GPS. The button changes colour to show status:
| Button state | Meaning |
|---|---|
| GPS OFF | GPS is not running. Tap to start. |
| GPS… | Acquiring a fix. Wait for it to turn green. |
| GPS LIVE | GPS is active and feeding ground speed to the gauge. |
If GPS permission was previously denied, use 📍 GPS Permission in the Setup page to attempt to repair it, or follow the instructions shown to fix it in your device settings manually.
iOS: Settings → Privacy & Security → Location Services → find Safari or this app → set to While Using.
Android: Settings → Apps → this app/browser → Permissions → Location → Allow.
The ground speed gauge is a deviation instrument — read it at a glance without focusing on numbers, the same way you read an airspeed indicator. Clockwise = faster; counter-clockwise = slower.
The target speed selector sits at 12 o'clock on the gauge — tap it to change the value. That number defines the centre of the arc. Min and max (±10 kts) are shown at 9 and 3 o'clock. Outside that window the needle pegs. The green band at 12 o'clock marks on-speed (±3 kts). The large central number is actual ground speed in knots.
Choose target speed based on conditions, pilot preference, and sea-scoop configuration.
Tap the number at 12 o'clock to change target speed, then drag the slider.
Log entries are stored locally on the device. Exporting to CSV or TXT is the only way to back them up — no cloud sync is performed.