A significant Center of Gravity (CG) shift between takeoff and landing may be due to an incorrect gear retraction moment value. As depicted below, when this error is present, large horizontal lines are displayed next to the takeoff and landing values, often exceeding the aircraft's CG limits.
CG envelope with a significant shift
What is the gear retraction moment?
The gear retraction moment is the change in CG that occurs due to the raising and lowering of the landing gear. This shift in CG should be depicted as a short horizontal line next to the takeoff and landing weight as depicted in the image below.
Gear Retraction Moment Shift
How to correct a W&B profile
To correct a weight & balance profile that has an incorrect gear retraction moment value, follow the steps below:
- Select More > Aircraft.
- Scroll to the Weights section and tap the Weight & Balance profile.
- Scroll to the bottom of the view and verify the correct Gear Retraction Moment Change value is entered, paying close attention to the weight and length units.
- If necessary, edit the Gear Retraction Moment Change value.
NOTE: The Gear Retraction Moment Change value can be found in the aircraft flight manual. If the value provided in the aircraft flight manual does not match the unit of measure in ForeFlight, it will be necessary to convert the value using a program other than ForeFlight before entering it.