T-45C TS, ADV & IUT ENG-20
Flight Instruments Malfunctions
a. Instruments affected in both cockpits
b. Cross-check with other aircraft information
c.
Cross-check airspeed with AOA indicator
3. Effect on flight safety: unreliable standby airspeed, standby altitude,
and standby VSI
NOTE: In these circumstances, you would use AOA for airspeed
and the radar altimeter (below 5000 ft AGL) and/or ATC for altitude.
Further, with pressurization off, you could use the cabin altimeter for
MSL altitude.
III. Angle of attack (AOA) system
Fig 3: AOA Instru-
ments: Summary of
A. AOA indicator failure
Malfunction Indica-
tions and Verifications
1. Indications
a. Needle freezes or is erratic and unreliable
b. OFF flag may appear
2. Verifications
a. Needle does not respond to noseup/down stick inputs
b. Cross-check with standby airspeed indicators in landing
configuration
c.
Cross-check with digital readouts on ADI display and HUD
d. Cross-check indicator in other cockpit and/or other aircraft
3. Effects on flight safety: loss of AOA indexer lights (both cockpits)
and external approach lights. Also loss of rudder shaker and stall
warning tone
B. AOA indexer failure
1. Indications
a. Fails to light with gear down
b. Light pattern erratic and unreliable
2. Verifications
a. Cross-check with AOA indicator
Original (9-98)
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