The Atitude Indicator - Ch 16

Question 1

Also known as

Answer 1

AI - Attitude Indicator

ADI - Attitude and Direction Indicator

EADI - Electric Attitude and Direction Indicator

Question 2

Operation

Answer 2

Provides datum against pitch and roll: attitude can be measured

Rotor is horizontal with 2 degrees of freedom: 2 gimbals

Vertically tied by gravity : Earth gyro

Question 3

Display

Answer 3

Horizon moves - shows attitude relative to the gyro

Accurate display: amplifier used as it has a narrow range for small pitch angle

Question 4

Pointer Methods

Answer 4

Ground/Sky: Shows you how many degrees AoB you are

Very precise

Question 5

Pneumatic Erection

Answer 5

Exhaust portal half covered by pendulous vanes which keep the gyro horizontal when there is any movement.

Total precession pushes the gyro back

Question 6

Electric Erection

Answer 6

Two electric torque motors (roll/pitch) and two mercury switches (roll/pitch)

Mercury switches energise the electric motor in the opposite direction which is then processed at 90 degrees

Question 7

Rate of Erection

Answer 7

Relatively slow

Compensates for: ER, TW, RW

Question 8

Errors (pneumatic)

Answer 8

Instrument errors: HDG change/Turning can cause gyro misalignment

Pendulous errors: Lateral Accel.: causes pitch error
Linear Accel.: causes roll error

Question 9

Classic Instrument (anticlockwise rotation)

Answer 9

Accel: False indication of Climb and turn to the right
Decel: False indication of descent and turn to the left

Question 10

Electric Errors

Answer 10

Are relatively small and insignificant

Gentle turns / acceleration can cause erection errors
Accel: Pitch Up Decel: Pitch Down
Turning: Under indication

Question 11

Pneumatic Instrument limits:

Answer 11

Pitch +/- 60

Roll +/- 110

Question 12

Electric Instrument Limits

Answer 12

Pitch +/- 85

Roll: Unlimited