FAA Aircraft Dispatcher (ADX)Regulations (Part 121)Medium
A Part 121 certificate holder is configuring a new airplane type with 45 passenger seats. Under 14 CFR 121.318, what public address (PA) system capability is required?
- AA PA system is not required because seating capacity is below 60
- BA PA system that shares circuitry with the interphone and only activates automatically during emergencies
- CA PA system independent of the crewmember interphone system, audible and understandable at all passenger seats, lavatories, and flight attendant seats
- DA PA system that only needs to be audible in the first 10 rows near the cockpit
Show answer & explanationAnswer & explanation
Correct answer: C. A PA system independent of the crewmember interphone system, audible and understandable at all passenger seats, lavatories, and flight attendant seats
14 CFR 121.318 requires airplanes with a passenger seating capacity of more than 19 to have a public address system that operates independently of the crewmember interphone system and is audible/understandable throughout the passenger cabin, including lavatories and flight attendant seats.
Why the other options are wrong
- A. The PA threshold is 19 seats, not 60, so 45 seats requires one.
- B. The PA system must be usable at any time, not only automatically in emergencies, and independent of the interphone.
- D. The PA must cover the entire cabin, not just forward rows.
PA System Requirement (121.318)
Airplanes with more than 19 passenger seats must have a public address system, independent of the interphone, audible throughout the cabin including lavatories and flight attendant seats.
- Threshold: more than 19 passenger seats
- Must be independent of crewmember interphone
- Must reach all passenger seats, lavatories, and flight attendant stations
Memory trick: 'Nineteen's the number — PA turns on louder.'