KLM MD-11 - Aircraft Communications Addressing and Reporting System (ACARS)

MD-11 Flight Crew Operations Manual
k
Communications -
Description and Operation
Comm.10.7
Aircraft Communications Addressing and Reporting System
(ACARS)
The Aircraft Communications Addressing And Reporting System (ACARS)
provides two-way data communications. Aircraft flight operations and
maintenance data is collected automatically from systems and sensors, or is
entered manually into the ACARS Management Unit (MU) through the MCDU,
for downlink. The crew may also enter free text messages, weather report
requests, and position reports.
Data that can be uplinked and downlinked includes all of the following:
• Flight plan (Downlinked).
•Load.
• Wind (Downlinked).
• Position report data/requests.
• Weather reports.
• Free text messages.
• Emergency messages.
• Airlines application.
An ACARS Management Unit (MU) is installed in the avionics rack and does the
following:
• Receives the ground-to-air messages.
• Controls transmission of the air-to-ground messages.
• Collects data from various airplane systems.
• Converts digital data in receive and transmit modes.
The MU receives data from:
•MCDUs.
• FMCs.
• Digital Flight Data Acquisition Unit (DFDAU) or Data Management Unit
(DMU).
• CFDS.
• VHF3 system.
• Door sensors.
• Parking brake.
• Air/ground switch.
•SATCOM.
Ground and satellite networks are responsible for transporting messages between
the aircraft and the airline host computer, and are operated by different providers,
depending on location.
VHF3 radio or SATCOM communication is available as follows:
November 10, 2008