Chapter 4 - Section 1: Passenger or cabin address Flashcards
What is the priority level of the PA system?
- Flight crew announcements
- Cabin crew announcements
- Pre-recorded announcements
- Boarding music
What do the regulations stipulate in the event of failure of the PA systems?
A megaphone is required
Why do loudspeakers contain one red terminal and one blue terminal?
Prevent audio ‘dead spots’ caused by one speaker cone moving inwards, rarifying the air, while an adjacent cone modes outwards, compressing the air
Describe the microphone select switches on the audio selector panel?
- Connect the microphone to the radio transceiver, cabin or service interphone, or PA system
- Push-on/push-off
- Mechanically interlocked so that only one may be pressed at a time
- Depressed switch illuminates white
When the BOOM/MASK toggle switch is selected to MASK, what is bypassed?
The INT switch, to provide continuous interphone audio service
What does the spring-loaded momentary RT switch permit when operated?
Operates directly into the selected transmitter without operating relays, permitting control of the transmitter in the absence of power to the audio selector panel
What happens when the VOICE/RANGE switch is depressed?
The 1020 Hz signal is attenuated and the DME identity signal is switched out
What happens when a cabin location is dialled from one of the cabin interphone headsets or the pilot’s call panel?
A pink call light and a hi-lo chime are activated at the called station
What happens when the flight compartment is dialled from a cabin handset?
Blue location indicator light is activated on the pilot’s call panel and a hi-chime is generated
What conditions will the ground crew call horn sound for in the nosewheel well area in ‘on ground’ conditions?
- Equipment cooling systems low airflow or overheat sensors activated
- Loss of 28v DC power to the aft and forward equipment cooling airflow sensors and overheat relays
- Any IRS turned on, or left on, and being powered by the hot battery bus in lieu of normal aircraft power
When will amplifier gain be increased in the passenger address system?
If an engine is operating or the oxygen system is deployed
Which pre-recorded announcement is not available for selection at the FAP?
Emergency decompression announcement A1
What does the microphone circuit of the attendant’s headset contain?
Noise-cancelling dynamic microphone and solid state pre-amplifier
What is the red LED on the main amplifier?
Overload indicator, indicating a fault in the system causing an overcurrent in the main amplifier
When can it be assured that the red LED is illuminated for a fault within the amplifier and not somewhere else in the circuit?
During AMP TEST, since the speaker circuit is effectively disconnected
