The Atitude Indicator - Ch 16 Flashcards Preview

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Flashcards in The Atitude Indicator - Ch 16 Deck (12):
1

Also known as

AI - Attitude Indicator

ADI - Attitude and Direction Indicator

EADI - Electric Attitude and Direction Indicator

2

Operation

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

3

Display

Horizon moves - shows attitude relative to the gyro

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

4

Pointer Methods

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

Very precise

5

Pneumatic Erection

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

Total precession pushes the gyro back

6

Electric Erection

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

7

Rate of Erection

Relatively slow

Compensates for: ER, TW, RW

8

Errors (pneumatic)

Instrument errors: HDG change/Turning can cause gyro misalignment

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

9

Classic Instrument (anticlockwise rotation)

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

10

Electric Errors

Are relatively small and insignificant

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

11

Pneumatic Instrument limits:

Pitch +/- 60
Roll +/- 110

12

Electric Instrument Limits

Pitch +/- 85
Roll: Unlimited