Compass Systems

Question 1

What is the purpose of a direct indicating compass

Answer 1

Points magnetic north using the horizontal component of the earths magnetic field

Question 2

3 properties of a direct indicating compass

Answer 2

Sensitivity - magnets in pairs
Horizontally
Aperiodicity

Question 3

Why is true north used

Answer 3

Never changes
Used as reference on maps and charts

Question 4

Difference between true and magnetic north is called

Answer 4

Variation

Question 5

What 2 magnetic effects can reduce the accuracy of a compass

Answer 5

Hard ion
Soft iron

Question 6

Hard iron effects

Answer 6

Vibration from engine or riveting
Aircraft in one location for too long
Lightening strike
Certain equipment fitted

Question 7

Soft iron effects

Answer 7

Weapons
Cargo
DC in aircraft electrical systems

Question 8

Count + dooku = milks + vaders = tits

Answer 8

Compass swing + deviation = magnetic + variation = true

Question 9

Explain Magnetic detector units purpose where it’s fitted on the a/c explain reason for location

Answer 9

The MDU senses the horizontal component of the Earth’s magnetic field and transmits the heading information electrically. And monitors directional gyro

Fitted in wing tips or the fin away from aircraft magnetic fields

Question 10

The Gyro Magnetic Compass System Annunciator is displaying the following indications. Briefly explain each indication.

Answer 10

XO - gyro is synchronised
X - gyro is de synchronised
O - gyro is de synchronised
DG - MDU is no longer monitoring the gyro and is using DG heading only

Question 11

Purpose of DG servo loop

Answer 11

To drive the compass card