Contact support
To help us reproduce an issue, include your iPhone or iPad model, iOS or iPadOS version, app version, the calculator side you were using and the steps that led to the problem. A screenshot is useful when it is safe to share.
App access and the free trial
- All app features require an active monthly auto-renewable subscription.
- Eligible new subscribers can start a 3-day free trial. The App Store shows eligibility and the localized monthly price before confirmation.
- Unless canceled at least 24 hours before it ends, the trial automatically becomes the monthly subscription shown by Apple and continues to renew until canceled.
- Use Restore Purchases after reinstalling the app or moving to another device using the same Apple Account.
- Manage or cancel through Apple Account subscription settings. Deleting the app does not cancel a subscription.
If access remains locked after a successful purchase or restore, confirm that the device is online, reopen the app and tap the retry or restore control once. Store availability and entitlement verification are provided by Apple.
Using the calculator
- Use the side switch to move between the circular slide-rule side and the wind side.
- Drag the movable calculator elements to align the scales or position the wind marker. Use the zoom controls or pinch gesture when you need a wider or closer view.
- Open the menu for Simulation, Practice, Quiz, guided tutorials, About, subscription management and support links.
- The simulator and its calculation assets are included in the app and do not need an internet connection after subscription access has been verified.
If a control appears displaced, return the view to 100%, change to the other side and back, or close and reopen the app. When reporting a repeatable alignment issue, include the device orientation and zoom percentage.
Circular slide-rule side
The front side supports multiplication and division; time, speed and distance; fuel-burn calculations; true airspeed and density-altitude practice; and common aviation conversions.
For a reliable reading, zoom in enough to distinguish adjacent scale marks, align the intended index carefully and read the matching scale. E6B scales require the pilot to determine the correct order of magnitude from the problem context.
Wind side, TAS and groundspeed
The wind side supports wind-correction angle, heading and groundspeed work. Position the wind mark, set the relevant speed and course values, and read each result from its labeled indicator.
If a marker is difficult to see or a value seems to move with the wrong control, reset the view, confirm that you are on the wind side and repeat the setup from the beginning. Include the entered wind direction, wind speed, course, TAS and resulting display values in a support request.
Tutorial, Practice and Quiz
Guided tutorials explain individual components and calculation workflows. Practice and Quiz generate problems for the available calculation categories. These modes are educational aids and do not replace instructor guidance, approved training material or operational flight planning.
If a modal or menu does not close, tap its visible close control once. If the screen remains unresponsive, close and reopen the app and report the exact mode and step where it happened.
Operational and safety limits
Before using a result operationally, independently verify calculations with approved aircraft documentation, current official information, applicable procedures and your own calculations. Do not rely on this app as the only source for a safety-critical decision.