4.7 ABNORMAL OPERATION
Abnormal operation of the system includes equipment failures of the system components and failure of
associated equipment, including switches and external devices.
STUCK MICROPHONE
If the push-to-talk (PTT) Key becomes stuck, the COM transmitter stops transmitting after 35 seconds of
continuous operation. An alert appears on the PFD to advise the pilot of a stuck microphone.
The MIC1, MIC2 or MIC3 Key Annunciator on the Audio Panel flashes as long as the PTT Key remains stuck.
COM TUNING FAILURE
In case of a COM system tuning failure, the emergency frequency (121.500 MHz) is automatically tuned in
the radio in which the tuning failure occurred. Depending on the failure mode, a red X may appear on the
frequency display.
AUDIO PANEL FAIL-SAFE OPERATION
If there is a failure of the Audio Panel, a fail-safe circuit connects the pilot' s headset (left ear only if stereo) and
microphone directly to the COM1 transceiver. Audio is not available on the speaker during Fail-safe operation.
190-01255-00 Rev. A
Figure 4-47 Stuck Microphone Alert
Emergency Channel
Loaded Automatically
Figure 4-48 COM Tuning Failure
Garmin G1000H
Pilot's Guide for the Bell 407GX
™
AUDIO PANEL AND CNS
133