Compass errors: acceleration and deceleration
On an east or west heading, speeding up or slowing down makes the compass show a turn that isn't happening.
MAGNETIC COMPASS
HEADING INDICATOR (actual heading)
1 · Pick a heading
2 · Change speed
Steady speed
The compass matches the heading indicator.
Airspeed 100 ktActual 090°Compass 090°
ANDS: Accelerate North, Decelerate South
- Northern Hemisphere. Largest on east and west headings, no error on north or south headings.
- The compass shows a turn toward north when you speed up, and toward south when you slow down.
- The airplane isn't turning. When the speed settles, the compass swings back to the correct heading.
- Only read the compass in straight, level, unaccelerated flight.