Terms of Use

Last updated: 21 September 2026

These terms cover your use of the Crabwise mobile app, provided by Volkan Günay (Vomcore), Ankara, Türkiye. Installing or using the app means you accept them. Contact: hello@vomcore.com.

What you get

A personal, non-exclusive, non-transferable licence to use Crabwise on devices you own or control. The app and its artwork stay ours.

Not for navigation

Crabwise is for training and reference only. It is not an approved source for navigation, flight planning, performance or weight and balance. Results come from standard textbook formulas and the values you enter; they do not account for your aircraft’s actual performance, instrument errors or real weather. Always use your aircraft’s flight manual (POH/AFM), official weather and charts, and the guidance of your instructor and aviation authority. The pilot in command is solely responsible for the safe conduct of every flight. Crabwise is not affiliated with or endorsed by the FAA or any other aviation authority.

Free and paid

The wind triangle and unit conversion are free. Crabwise Pro adds crosswind, time-speed-distance, fuel, altitude and airspeed, weight and balance, and the step-by-step working behind every answer.

• Subscriptions (weekly, monthly, yearly) renew automatically until you cancel. Cancel any time in your App Store account settings; cancellation takes effect at the end of the paid period.
• The yearly plan starts with a 3-day free trial. If you do not cancel before the trial ends, it becomes a paid year. The trial is offered once per subscription group, per App Store account.
• Lifetime is a one-time purchase, not a subscription, and carries no free trial.

Prices are shown in the app in your local currency before you buy. Payment is taken by Apple, and refunds are handled by Apple under its own rules — write to us and we will help you ask.

Apple’s standard Licensed Application End User License Agreement also applies: apple.com/legal/internet-services/itunes/dev/stdeula.

Restoring a purchase

Because there is no account, your purchase is tied to your App Store account. On a new device, sign in with the same account and use “Restore purchases” in Settings.

Acceptable use

Do not decompile, resell or redistribute the app, and do not try to unlock Pro features by tampering.

No warranty, and limits

Crabwise is provided “as is”, without warranty of any kind, including that any result is accurate or fit for a particular flight. To the extent the law allows, our total liability for any claim related to the app is limited to what you paid for it in the twelve months before the claim. Nothing here limits liability that cannot be limited by law, and your statutory consumer rights are unaffected.

Changes and ending

We may update the app and these terms; material changes are published here with a new date. You can stop using Crabwise at any time by deleting it. If you breach these terms, the licence ends.

Law

These terms are governed by the laws of the Republic of Türkiye, without prejudice to mandatory consumer protections in your country of residence.