Compass Errors

To receive accurate indications during flight from a heading indicator, the instrument must be

• set prior to flight on a known heading.

• calibrated on a compass rose at regular intervals.

• periodically realigned with the magnetic compass as the gyro precesses.

Deviation in a magnetic compass is caused by the

• presence of flaws in the permanent magnets of the compass.

• difference in the location between true north and magnetic north.

• magnetic fields within the aircraft distorting the lines of magnetic force.

The angular difference between true north and magnetic north is

• magnetic deviation.

• magnetic variation.

• compass acceleration error.

In the Northern Hemisphere, a magnetic compass will normally indicate initially a turn toward the west if

• a left turn is entered from a north heading.

• a right turn is entered from a north heading.

• an aircraft is accelerated while on a north heading.

In the Northern Hemisphere, a magnetic compass will normally indicate a turn toward the east if

• an aircraft is decelerated while on a south heading.

• an aircraft is accelerated while on a north heading.

• a left turn is entered from a north heading.

In the Northern Hemisphere, a magnetic compass will normally indicate a turn toward the north if

• an aircraft is decelerated while on an east or west heading.

• a left turn is entered from a west heading.

• an aircraft is accelerated while on an east or west heading.

In the Northern Hemisphere, the magnetic compass will normally indicate a turn toward the south when

• a left turn is entered from an east heading.

• a right turn is entered from a west heading.

• the aircraft is decelerated while on a west heading.

In the Northern Hemisphere, if an aircraft is accelerated or decelerated, the magnetic compass will normally indicate

• a turn momentarily.

• correctly when on a north or south heading.

• a turn toward the south.

During flight, when are the indications of a magnetic compass accurate?

• Only in straight-and-level unaccelerated flight.

• As long as the airspeed is constant.

• During turns if the bank does not exceed 18°.

In the Northern Hemisphere, a magnetic compass will normally indicate a turn toward the north if:

• a left turn is entered from a west heading.

• an aircraft is decelerated while on an east or west heading.

• an aircraft is accelerated while on an east or west heading.