Type training · Boeing 737 Classic B2 · ATA 23
Boeing 737 Classic B2: Communications (ATA 23)Type training questions & answers
HF and VHF radios, SELCAL, ELT, ACARS, passenger address, audio panels and the cockpit voice recorder.
- A worked explanation on every question
- Written for the 737-300/400/500 avionics
- Read in English or 15 other languages
Sample Communications questions with answers
Three questions from the free preview. Think of your answer first, then open the explanation.
1.What power does the 737 Classic HF system use?
- A.28 V dc from the battery bus
- B.115 V ac single-phase standby bus
- C.115 V ac three-phase, 400 Hz
Show answer and explanation
Correct answer: C. 115 V ac three-phase, 400 Hz
The HF systems use three-phase 115 V 400 Hz; HF-1 from P18 and HF-2 from P6. Ref 737-300/400/500 AMM 23-11-00.
2.What does a 737 Classic HF antenna coupler do on a new frequency?
- A.It switches between antennas in turn
- B.It raises the transmitter output power
- C.Tunes the antenna to 50 ohms
Show answer and explanation
Correct answer: C. Tunes the antenna to 50 ohms
A rechannel signal starts a tune cycle that matches the antenna to 50 ohms. Ref 737-300/400/500 AMM 23-11-00.
3.How long does a 737 Classic HF coupler tune tone last at most?
- A.15 seconds
- B.3 seconds
- C.60 seconds
Show answer and explanation
Correct answer: A. 15 seconds
A 1,000 Hz tune tone sounds while tuning, no longer than 15 s; average tune time is about 1 to 7 s. Ref 737-300/400/500 AMM 23-11-00.
Part of the Boeing 737 Classic B2 type course
One chapter of the Boeing 737 Classic B2 type course question bank, for the 737-300/400/500 avionics, written in our own words for revision. Your type course and the aircraft maintenance manual stay the authority: limits and procedures can differ between airframes and operators.
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