PS Engineering PMA4000 Pilot’s Guide - Manual (Page 6)

6 PMA4000 TSO-Pilot Guide & User Manual
radio and transmit sidetone). This will be heard in all headsets and speaker
(if selected). To hear older messages, push the playback button repeatedly
to “back up” the recorder, until the desired message is heard.
Holding the IRS playback button for three seconds will stop the message
playback and queues the system to the next preceding message. This allows
quick access to previous messages.
The recorder is a continuous loop, and newest ones will overwrite the old-
est messages.
The IRS has an internal squelch that prevents storing ‘dead’ air. A radio
signal of more than 1 VRMS is needed to trigger the IRS. Therefore, if the
IRS does not seem to be recording, increase the aircraft radio volume
slightly.
Limitations
Any entertainment device connected through the PMA4000 must be
switched off during take off and landing.
Emergency Procedures
In the event that the unit exhibits any anomalous behavior, such as an audio
failure, transmitter failure, or other difficulty, the unit can be switched off
in the following manner:
1. Placing the Intercom Mode Selector Switch (see Figure 1-2) into
the “OFF” position.
2. Pulling the Audio Panel Circuit Breaker.
This activates the fail-safe mode, which connects the pilot’s headset di-
rectly to Com 1. This allows communications or the pilot only, on Com 1
only.