STANDBY GYRO FAILURE
As opposed to an ADI 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. Of course, if the ADI has previously failed or if its
indications are suspect, a standby gyro failure becomes a serious matter.
Figure 44 shows one of the possible indications of a failed standby gyro. Remember that 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 power.
NOTE: After loss of power with the power off flag in view, the 3 inch standby gyro will continue to
provide reliable altitude reference for up to 3 minutes after failure. In cockpits where the new 2-inch
standby gyro is installed, it will continue to provide reliable altitude reference for up to 9 minutes after
Figure 44: FAILED 3 STANDBY GYRO/FAILED 2 STANDBY GYRO
The procedure for dealing with a standby gyro failure is:
Use the ADI.
Check the electrical system.
Watch for possible progressive failure.