737 MAX Flight Crew Operations Manual
Communications
Chapter 5
System Description
Section 20
MN-FLT-OH-201
5.20.1
20 System Description
System Description
File Highlight
Introduction
The communication system includes:
• radio communication system
• interphone communication system
• cockpit voice recorder system
• communication crew alerting system
The communication systems are controlled using the:
• audio control panels
• radio tuning panels
Audio Systems and Audio Control Panels
An ACP is installed at the Captain, First Officer, and Observer stations. Each
panel controls an independent crew station audio system and allows the
crewmember to select the desired radios, navigation aids, interphones, and PA
systems for monitoring and transmission.
Transmitter selectors on each ACP select one radio or system for transmission by
that crewmember. Any microphone at that crew station may then be keyed to
transmit on the selected system.
Receiver switches select the systems to be monitored. Any combination of
systems may be selected. Receiver switches also control the volume for the
headset and speaker at the related crew stations. Audio from each ACP is
monitored using a headset/headphones or the related pilot’s speaker.
Audio warnings for altitude alert, ground proximity warning, traffic collision
avoidance advisories and radar predictive windshear alerts are also heard through
the speakers and headsets at preset volumes. They cannot be controlled or turned
off by the crew.
Speakers and Headsets
Each crew station has a headset or headphone jack. The Captain and First Officer
have speakers on the ceiling above their seats. There is no speaker at the observer
station. Headset volume is controlled by the receiver switches. Speaker volume is
controlled by the receiver switches and also the speaker switch. The speakers
always operate during ground proximity warnings, altitude alert warnings, traffic
collision avoidance advisories and radar predictive windshear alerts.
March 1, 2021
