If EFIS magnetic interference is known, which COMPASS setting should be used during takeoff and climb until takeoff is complete?

If EFIS magnetic interference is known, which COMPASS setting should be used during takeoff and climb until takeoff is complete?

• A. MAG; takeoff
• B. MAG; climb
• C. OFF; takeoff
• D. OFF; climb

Answer: (A)

When you have known EFIS magnetic interference, you still want a stable, real-world heading reference during the most demanding phase of flight—the takeoff and initial climb. Setting the compass to MAG uses the magnetic heading source, keeping the EFIS display aligned with the magnetic reference that ATC and standard procedures rely on for runway alignment and initial heading tracking. This gives you a consistent, familiar reference right when you need it most. The instruction to use this mode only until takeoff is complete reflects that once the takeoff maneuver is finished and the airplane is in stable climb, you can revert to the normal configuration. Using OFF would remove the magnetic reference entirely, which is not desirable during the critical takeoff phase, as it could leave you with less reliable heading information.

When you have known EFIS magnetic interference, you still want a stable, real-world heading reference during the most demanding phase of flight—the takeoff and initial climb. Setting the compass to MAG uses the magnetic heading source, keeping the EFIS display aligned with the magnetic reference that ATC and standard procedures rely on for runway alignment and initial heading tracking. This gives you a consistent, familiar reference right when you need it most. The instruction to use this mode only until takeoff is complete reflects that once the takeoff maneuver is finished and the airplane is in stable climb, you can revert to the normal configuration. Using OFF would remove the magnetic reference entirely, which is not desirable during the critical takeoff phase, as it could leave you with less reliable heading information.