This app can help you to know your altitude, ground speed .It's including a Compass GPS that shows direction relative to the geographic cardinal directions, with true and magnetic North. Also you can detect any turbulence and incline of airplane relatively to horizontal position. 1. Compass -- Shows device real-time orientation to magnetic fields. -- Ability to switch between true and magnetic North 2. Turbulence --Seismometer graph --X, Y, Z axes