Northern Airborne Technology AA22 - Manual (Page 11)

AA22 Series PA Driver/Siren Control
SM33-2 Installation and Operation Manual
Section 2 Rev: 1.00 Issue 4 Page 2-4
ENG-FORM: 805-0115.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
sound absorbing material from the speakers before flying the aircraft. To achieve the best
operation, all voice commands must be spoken slowly and clearly, with extra emphasis on each
word.
To determine the operational capability of the system, put the aircraft in a hover and with the
target properly positioned, provide PA instruction to the target to accomplish a certain task that
will give visual cue to the flight crew that the target has understood the instructions (i.e., "touch
your head", "sit down", "turn around", etc.)
2.4.4.3 Power On Checks
Power up the aircraft’s systems and confirm normal operation of all functions of the AA22. Refer to
Section 3 (Operation) for specific operational details.
a) Turn on all of the radios and other accessories required for this system. Check that the power
ON LED on the AA22 illuminates when the power switch is up.
b) Key the siren using the front panel button or remote siren key. The siren should sound and
the level should be at maximum volume (the front panel level control does not affect the
siren). If the siren (rate or tone) needs adjustment there are two trimpots on the left side of
the AA22.
c) Select the rest of the audio system as required to allow connection of the pilot's mic to the
‘PA’ and key the cyclic switch for transmit. The mic audio should be heard on the ‘PA’
speakers. Adjust the front panel level control for the desired volume.
d) Check preset adjustments are completed before aircraft departure.
Notes: 1. Note that PA audio has priority in the AA22 system and it will be heard even if the panel
switch is selected to ‘RADIO’. Check for correct radio operation and note what volume
settings will produce a suitable external paging level. .
2. A faint audio signal may be heard at the speaker (even when the system is not paging) due to
the very high gain of this system and stray coupling in the wiring. It should not be audible in
flight.
Upon satisfactory completion of all performance checks, make all required log book entries, electrical
load, weight and balance amendments and other documentation as required by your local regulatory
agency before releasing the aircraft for service.
2.5 Adjustments and Connections
If any preset requires adjustment, be sure this is carried out before the aircraft leaves and that the unit
and its mating connector are secured before departure.
If the siren does not suit the specific requirements of a given installation, the following adjustments are
available:
1. Base tone setting - potentiometer marked TONE.
2. Sweep rate setting - potentiometer marked RATE.
These controls are accessible through holes on the left side of the unit as shown in Figure 1.