FAA Aviation Mechanic Airframe (AMA)Airframe Electrical and InstrumentsEasy
A technician swings the magnetic compass of an aircraft on a compass rose and records the difference between the compass indication and the actual magnetic heading at various headings. What is this recorded information used to create?
- AAn adjustment factor for the vertical speed indicator
- BA deviation card mounted near the compass
- CA variation correction chart for the aircraft's logbook
- DA calibration certificate for the flux valve
Show answer & explanationAnswer & explanation
Correct answer: B. A deviation card mounted near the compass
Compensating (swinging) the compass produces correction values for various headings, which are recorded on a deviation card placed near the compass so the pilot can apply corrections for known deviation errors caused by the aircraft's own magnetic influences.
Why the other options are wrong
- A. The compass swing has no relationship to the vertical speed indicator.
- C. Variation is a geographic property between true and magnetic north, not something adjusted per aircraft.
- D. A flux valve calibration certificate is not the product of a manual compass swing.
Compass Deviation Card
A placard mounted near the magnetic compass showing the correction to apply for deviation errors at various headings, created by swinging the compass on a compass rose.
- Deviation is caused by aircraft's own electrical and magnetic equipment
- Compass swing is performed on a calibrated compass rose
- Card typically lists corrections every 30 degrees
- Should be re-swung after avionics installation or major electrical changes
Memory trick: Swing the compass like a pendulum on the rose to write the 'cheat sheet' card for the pilot.