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Audio Panel Operation
munication capability regardless of the condition of the unit. Any time power is removed or turned off, the audio selector is placed in the EMG mode.
In the EMG mode, one or two of the unswitched audio inputs are sup- plied to the pilot headset. Also, in the EMG mode, audio signals are pre- sent in only one ear of a stereo headset.
MARKER BEACON OPERATION
The marker beacon receiver uses visual and audio indicators to alert the crew when the aircraft passes over a 75 MHz transmitter. There is a service adjustment located on the unit for ground maintenance to adjust the marker audio volume level.
The outer, middle and inner marker indications are shown on an exter- nal display. The audio panel supplies a
The MKR SENS button is used to set the receiver sensitivity and to test the marker beacon. Use high (HI) sensitivity initially. This allows you to hear the outer marker beacon about a mile out. Then push the MKR SENS button to switch into the low (LO) sensitivity mode. Low sensitivi- ty gives you a more accurate location of the marker. Many pilots choose to leave the button in the low sensitivity mode.
Pressing and releasing the MKR MUTE/TEST button causes the mark- er audio to mute for that beacon. The muting continues until one of the following events occurs:
1.A marker tone is detected that is different from the one that was present when MUTE was initiated or if the same tone returns after a delay. (The delay accounts for a tone that fades and then comes right back. The MUTE is reset if the aircraft is flown out of the cur- rent tone and then back in.)
2.The audio panel is turned OFF.
3.If MUTE is pressed prior to crossing the marker beacon, the mute will continue for 60 seconds and then timeout.
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Sep/07 | KMA 29 Audio Panel Pilot’s Guide | 13 |
