2.1: The Magnetic Compass

Question 1

During flight, when can a magnetic compass be considered accurate?

Answer 1

Only during straight-and-level flight at constant speed.

Question 2

What is (compass) deviation?

Answer 2

deviation is the difference between the direction indicated by a compass not installed in an airplane and one installed in an airplane.

Question 3

In the Northern Hemisphere, what acceleration/deceleration compass error occurs?

Answer 3

When flying in a East or West direction, the compass will indicate a turn to the North during acceleration and will indicate a turn to the South during deceleration.

Memory Aid: ANDS - Accelerate North, Decelerate South

Question 4

In the Northern Hemisphere what compass error occurs when turning from a north heading?

Answer 4

A magnetic compass will lag and at the start of a turn, indicate a turn in the opposite direction when turning from the north.

Memory Aid: UNOS - Under shoot North, Over shoot South

Question 5

What is Compass deviation?

Answer 5

Compass deviation error is the difference between the heading indicated by a magnetic compass in an airplane and the airplane’s actual magnetic heading.

Question 6

Deviation in a magnetic compass is caused by the

Answer 6

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

Question 7

Compass errors include?

Answer 7

1. Magnetic variation
2. Compass deviation
3. Magnetic dip
4. Compass card oscillation

Question 8

What is magnetic variation?

Answer 8

Magnetic variation is that angular difference true north and magnetic north.

Question 9

What is magnetic dip?

Answer 9

Magnetic dip error is the tendency of the compass needles to point down as well as to the magnetic pole. The resultant error is known as dip error, which is greatest at the poles and zero at the magnetic equator.

Question 10

In the Northern Hemisphere what compass error occurs when turning from a south heading?

Answer 10

if an airplane on a southerly heading turns toward the east or west, the initial indication of the compass needle will show a greater amount of turn than is actually made.

Memory Aid: UNOS - Under shoot North, Over shoot South

Question 11

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

Answer 11

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

Question 12

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

Answer 12

Only in straight-and-level- unaccelerated flight.

Question 13

Deviation error of the magnetic compass is caused by

Answer 13

certain metals and electrical systems within the aircraft.

Question 14

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

Answer 14

correctly when on a north or south heading.

Question 15

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

Answer 15

the aircraft is decelerated while on a west heading.

Question 16

What should be the indication on the magnetic compass as you roll into a standard rate turn to the right from a south heading in the Northern Hemisphere?

Answer 16

The compass will indicate a turn to the right, but at a faster rate than is actually occurring.

Question 17

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

Answer 17

a left turn is entered from a north heading.