Aircraft Systems: CMC Switching and ARINC 429

Electronic Flight Bag (EFB)

• EFBs replace traditional reference materials like books and charts on flight decks.
• They are typically displayed on additional cockpit panel units.
• Civil Aviation Authorities define three classes of EFB hardware.

Class 1 EFB

• Class 1 EFBs are portable, Commercial Off-the-Shelf (COTS) systems for aircraft operations.
• They connect to aircraft power through a certified source but are not mounted in the cockpit.
• No prior administrative control is needed for use.
• Considered Portable Electronic Devices (PEDs).

Class 2 EFB

• Class 2 EFBs are also portable and COTS-based, meant for aircraft operations.
• They require mounting in the cockpit and airworthiness approval before usage.
• Connectivity to avionics is enabled.
• Can interface with Central Maintenance Computers (CMC) for data exchange.

CMC Functionality

• CMCs can communicate via ARINC 429 links allowing them to share status data and manage fault situations.
• Each CMC can determine which is the master based on fault status or manual selection.

Flight Warning Computers and ECAM

• Flight warning computers track operational data to provide real-time warnings and system information.
• Failures are logged in non-volatile memory for later recall; critical failures are displayed in real-time on the ECAM during the flight.
• System failures are classified into three categories based on their operational and safety impact.

Failure Classifications

• Class 1 Failures: Impact current flight operations, shown as real-time warnings on ECAM and MCDU.
• Class 2 Failures: No impact on current flight. Reported on ECAM STATUS page.
• Class 3 Failures: No operational or safety impact, only visible on the ground.

Software Management

• Field Loadable Software (FLS) is updated via Portable Data Loaders (PDL) or Airborne Data Loaders (ADL).
• Post-loading verification of software is required per maintenance manuals.
• Updates must be documented in the Aircraft Configuration List (ACL), with records maintained both on-board and in maintenance logs.

Electronic Library Systems

• Modern airlines use Digital Electronic Library Systems (DELS) to integrate various operational documents, replacing paper-based systems.
• DELS includes aircraft manuals, maintenance data, checklists, and is integrated with flight management systems.
• In emergencies, systems can quickly reference relevant checklists or operational manuals.

Aeroplane System Computers

• Various aircraft systems are tied to the Central Maintenance Computer (CMC) with distinct hardware connections.
• Type 1 Systems: Connected to both CMCs and can store failure data from the last 64 flights for troubleshooting.
• Type 2 Systems: Store failure data only from the last flight, activated by a discrete input for testing.

Test your knowledge of aircraft systems, including the interface between CMC 1 and CMC 2, ARINC 429 link, and cross-talk functionality. Learn about the role of CMC switching in ensuring system redundancy and fault tolerance. Prepare for your CASA Part 66 exam with this quiz.