Garmin G1000H Bell 407GX Pilot's Guide - Page 145

AUDIO PANEL AND CNS 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. Figure 4-47 Stuck Microphone Alert 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. Emergency Channel Loaded Automatically Figure 4-48 COM Tuning Failure 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 Garmin G1000H™ Pilot's Guide for the Bell 407GX 133