STANDBY GYRO FAILURE
As opposed to an ADI display failure, a
standby gyro failure is not a significant
problem. With this failure, you cannot use the
standby AI as a cross-check for the ADI
display. Of course, if the ADI display has
previously failed or if its indications are
suspect, a standby gyro failure becomes a
Figure 51 shows one of the possible
indications of a failed standby gyro. The
power off flag does not have to be present for
the indicator to give a false reading because
the flag signifies only a lack of electrical
NOTE: After loss of electrical power with the
power off flag in view, the 2-inch standby
gyro will continue to provide reliable attitude
reference for up to 9 minutes after failure.
Figure 51: FAILED 2 STANDBY GYRO
The procedure for dealing with a standby gyro
1. Use the ADI display.
2. Check the electrical system.
3. Watch for possible progressive failure.
AOA INDICATOR FAILURE
The loss of the AOA indicator will mainly
affect your approach scan: you will have to
use the digital AOA indication on the ADI
display. If the AOA indicator, AOA indications
on the ADI and HUD displays all fail, you will
have to fly airspeed instead of AOA. So you
omit the AOA indicator and indexer from your
scan, and focus on the airspeed trend
Figure 52 shows one of the possible
indications of a failed AOA indicator. The
OFF flag does not have to be present for the
indicator to give false readings because the
flag indicates only a lack of electrical power.
The procedure for dealing with an AOA
indicator failure is:
1. Use the indicated airspeed trend indicator.
Figure 52: FAILED AOA INDICATOR
2. Fly calculated approach speeds, using the
airspeed trend indicator.