On Board Maintenance System Overview

MCDU Function

• The MCDU serves as a central hub for aircraft data and functions, allowing pilots to access vital information and manage system operations.

BITE Acronym

• BITE stands for Built-In Test Equipment.

CMC Communication

• Multiple MCDUs can communicate with the Central Maintenance Computer (CMC).

System Component Independence

• The Central Maintenance Computer (CMC) is independent from its operational parts.

Maintenance Results Retrieval

• One way to retrieve maintenance results is through the Central Maintenance Computer (CMC).

CMC Functions

• The CMC processes and stores fault data.
• The CMC facilitates communication between MCDUs and other aircraft systems.
• The CMC helps to keep track of aircraft maintenance requirements.

CMC Interaction

• The Central Maintenance Computer (CMC) primarily interacts with the MCDU and other aircraft systems.

BITE Location

• The BITE is located within the aircraft's systems and helps to identify and diagnose faults.

MCDU Title Line Role

• The title line on the MCDU display provides context by indicating the current page or function.

MCDU Data Lines Arrangement

• The MCDU Display features multiple data lines arranged in a specific order for easy navigation.

Scratchpad/Message Line Purpose

• The scratchpad or message line serves as a communication channel for the operator, conveying messages or instructions.

Data Line Font Size

• Data lines in the MCDU Display are typically smaller than label lines, providing clearer hierarchy for information.

Data Line Organization

• Data lines are arranged in a logical manner, often grouped by related information or function.

MCDU Display Component

• The CMC (Central Maintenance Computer) is NOT a direct part of the MCDU Display.

Scratchpad Message Indication

• The message on the scratchpad line indicates a fault, warning, or system status.

MCDU Display Design

• The MCDU Display is designed to simplify information retrieval and communication for the operator.

ACARS Meaning

• ACARS stands for Aircraft Communications Addressing and Reporting System.

Asterisk Indicator (A340)

• The asterisk next to the line select key in the A340 MCDU display indicates an active function or selection.

CMCS Report Function Distinction

• Different types of MCDUs offer varying levels of CMCS report functions, influencing the data accessible to operators.

PRINT Message Function

• The Airbus A340 MCDU allows for a PRINT message function.

Line Select Key Purpose

• Line select keys on the MCDU allow users to navigate and activate specific lines or functions on the display.

MCDU Role in ACARS

• The primary role of the MCDU in the ACARS data link is communication and data transfer.

MCDU Display During CMCS Report

• During the CMCS report function, the MCDU display shows detailed maintenance information, including fault details, system status, and troubleshooting guidelines.

ACARS Display on 747-400 MCDU

• The 747-400 MCDU features a dedicated "ACARS" line that clearly indicates the status and communication channels of the ACARS data link.

Fault Message Indication

• A fault message primarily indicates a detected anomaly, malfunction, or deviation within a system.

Fault Analysis Component

• The BITE (Built-In Test Equipment) is primarily responsible for analyzing faults in aircraft systems.

CMC Fault Storage

• The Central Maintenance Computer (CMC) stores fault information along with the fault type, time of occurrence, and potential causes.

Data Source Purpose

• The data source displayed on the MCDU page provides context and identifies the origin of the information presented.

Fault Message Format

• A standardized fault message typically includes the affected system, the specific fault, the time of occurrence, and potential troubleshooting steps.

SFCC Role

• The Slat Flap Control Computer (SFCC) plays a role in identifying and reporting faults related to its controlled system.

Fault Message Location

• After a fault is detected and analyzed, the fault message is typically located at the CMC (Central Maintenance Computer) for further action.

BITE Acronym (Fault Analysis)

• BITE stands for Built-In Test Equipment, a component that helps diagnose and analyze faults in aircraft systems.

Hard Failure Definition

• A hard failure in aircraft systems is a permanent malfunction that completely prevents a system from functioning.

Intermittent Failure Characteristics

• An intermittent failure is characterized by a sporadic or unpredictable occurrence, where a system may function normally at times but malfunction at others.

Hard Failure Characteristic

• A hard failure is NOT characterized by its intermittent nature, as hard failures imply a permanent malfunction.

Post Flight Report Exception

• A failure is likely to NOT be recorded in a post flight report if it is a minor anomaly, does not significantly impact flight safety, and is easily resolved during pre-flight checks.

Continuous Failure Type

• A hard failure typically occurs continuously without interruption, meaning the system is permanently malfunctioning.

Pilot Description of Intermittent Failure

• A pilot might describe an intermittent failure during flight as a "temporary glitch", "sporadic issue", or "intermittent malfunction".

Failure Requiring Troubleshooting

• Intermittent failures usually require a troubleshooting process to identify the underlying cause and ensure a permanent solution.

Hard vs. Intermittent Failure Distinction

• The primary distinction between hard and intermittent failures lies in their consistency and predictability. Hard failures are permanent, while intermittent failures are sporadic and unpredictable.