Avionics bending: MCDP computer

A.

The maintenance monitor system consists of a Maintenance Control Display Panel (MCDP) that monitors the status of the Flight Control Computers (FCC), Flight Management Computers (FMC), Thrust Management Computer (TMC), and their related sensors. The MCDP interrogates the computers after each landing, and stores up to five flight faults per computer in non-volatile memory for later interrogation by maintenance personnel.

B.

A central processing unit in the MCDP controls and processes ground test commands, ground test functions, and on-ground and in-flight faults. The MCDP displays flight and ground faults, test number, name or status, and operator instructions. The MCDP controls and display panel are located on the front of the unit. The controls enable maintenance personnel to display faults and ground tests that include operator instructions. The MCDP is located in the main Electrical/Electronic (E/E) equipment center.

C.

The remote control panel is mounted in the P61 panel and is used for displaying flight faults and for running ground tests from the flight deck. The MCDP remote display is through the EICAS system maintenance panel in the P61 panel. The MCDP display can be displayed on the EICAS with or without the remote control panel, by pressing the CONF/MCDP switch of the EICAS maintenance panel.

D.

Maintenance Control Display Panel Interfacing Systems

 

(1) The primary MCDP interfaces are with each FCC, FMC, and TMC.Secondary interfaces with the MCDP consist of FCC, FMC, and TMC individual system sensors. Both primary and secondary interfaces are monitored by the MCDP during ground test functions.

(2) Primary Interfaces

(a) The left, center, and right flight control computers use ARINC 429 data buses for transmitting interface fault data to the MCDP and receiving ground test data from the MCDP. Analog discrete lines are used for ground test control.

(b) The left and right flight management computers use ARINC 429 data buses to transmit interface fault data to the MCDP. The MCDP can only interrogate the FMC for fault data. The MCDP ground tests do not affect the FMC systems.

(c) The thrust management computer uses an ARINC 429 data bus for transmitting interface fault data to the MCDP and receiving ground test data from the MCDP. An analog discrete line is used for ground test control of the TMC by the MCDP.

(3) Secondary Interfaces

(a) The mode control panel supplies control signals and receives status data from each FCC, FMC, and TMC on ARINC 429 data buses.

(b) Each FCC supplies analog control signals to its control servos and receives analog servo position signals. Each FCC receives sensor data on ARINC 429 data buses from the

associated Inertial Reference Unit (IRU) and air data computer.

(c) The TMC receives control signals on an ARINC 429 data bus from the thrust mode select panel. The TMC also transmits status data to the thrust mode select panel on an ARINC 429 data bus. The TMC supplies analog control signals to and receives analog

position signals from the autothrottle servomotor generator.