Aircraft Digital Systems and BITE

Questions and Answers

What is a primary consideration in designing complex digital aircraft systems?

Ability to troubleshoot (correct)

Reduced weight

Increased fuel efficiency

Ease of inspection

Which system provides self-diagnostic capabilities in modern digital aircraft?

EFIS

GPS

ECAM

BITE (correct)

What is the primary function of the Aircraft Communications Addressing and Reporting System (ACARS)?

Inertial reference

Flight management

Communication and reporting (correct)

Engine indicating and crew alerting

Which system is responsible for providing flight instrument data to the pilots?

EFIS Signup and view all the answers

What is the primary function of the Traffic Alert and Collision Avoidance System (TCAS)?

Traffic alert and collision avoidance Signup and view all the answers

Which system provides centralized monitoring of aircraft systems?

ECAM Signup and view all the answers

What is the primary function of the Fly-By-Wire (FBW) control system?

Flight control Signup and view all the answers

Which system provides navigation data to the pilots?

GPS Signup and view all the answers

What is the acronym for Built-In Test Equipment?

BITE Signup and view all the answers

What is the main advantage of advanced BITE systems like CMCS and CFDS?

They are more easily accessible and understood than older systems Signup and view all the answers

What is the primary function of a BITE system?

To troubleshoot electronic/avionics systems Signup and view all the answers

What is the name of the advanced diagnostic system used by Airbus?

CFDS Signup and view all the answers

What is the typical display of a simple BITE system?

A go/no-go red or green LED Signup and view all the answers

How many LRUs are used in a Boeing 757 or 767 aircraft for built-in test equipment systems?

50 Signup and view all the answers

What is the name of the advanced built-in troubleshooting system used by Boeing?

CMCS Signup and view all the answers

What is a feature of some BITE systems?

They can test the associated wiring Signup and view all the answers

What is the main purpose of BITE in aircraft systems?

To monitor the internal LRU circuits and identify possible failures Signup and view all the answers

What can BITE identify when a failure occurs in an LRU?

The possible failed LRU and determine if the failure is intermittent or permanent Signup and view all the answers

Where is the BITE section typically located in an aircraft system?

In the electronics equipment bay Signup and view all the answers

What happens to the details of a failure when it occurs in an aircraft system?

They are saved in a non-volatile memory for later analysis Signup and view all the answers

What is an LRU in the context of aircraft systems?

A black box or a sensor Signup and view all the answers

What is the function of the BITE section during normal operation?

To continuously monitor the internal LRU circuits, the LRU inputs and outputs, and the links between system LRUs Signup and view all the answers

What is the primary purpose of the power up test in a BITE system?

To ensure compliance with safety objectives on the ground Signup and view all the answers

What is a characteristic of cyclic tests in a BITE system?

They are performed permanently without disturbing system operation Signup and view all the answers

What is tested during a power up test in a BITE system?

The microprocessor, memories, data lines, and input/output circuits Signup and view all the answers

What is the significance of the 200 millisecond power cut in a BITE system?

It is the threshold below which a power up test is not executed on the ground Signup and view all the answers

What is the purpose of a watchdog in a cyclic test?

To restart the microprocessor if the software fails Signup and view all the answers

What is the benefit of using a centralised maintenance device in a BITE system?

It provides a single interface location Signup and view all the answers

How often are cyclic tests performed in a BITE system?

Permanently without disturbing system operation Signup and view all the answers

What is a benefit of using BITE in an aircraft system?

It simplifies technical documentation Signup and view all the answers

What is the main purpose of the system test?

To check the integrity of the system after restoration Signup and view all the answers

What can specific tests available for some systems generate?

Stimuli to various command devices Signup and view all the answers

What is the primary function of the Maintenance Control Display Unit (MCDU)?

To send commands to connected systems Signup and view all the answers

Which system component can be accessed through the MCDU?

Flight Management System Signup and view all the answers

What is the purpose of running a complete operational check after repairs?

To verify correct system operation Signup and view all the answers

What monitors the system and verifies correct operation after repairs?

The BITE system Signup and view all the answers

What is a system that can be accessed through the MCDU?

Aircraft Condition Monitoring System Signup and view all the answers

Study Notes

Typical Electronic/Digital Aircraft Systems

Describe the general arrangement of typical electronic/digital aircraft systems and associated Built-In Test Equipment (BITE)
BITE is used for self-diagnostic systems troubleshooting, making it easier to troubleshoot complex digital aircraft systems
There are several versions of built-in test equipment, ranging from simple go/no-go LED indicators to complex systems with multi-character displays and centralized monitoring systems

Aircraft Communications Addressing and Reporting System (ACARS)

ACARS is a typical electronic/digital aircraft system with BITE capabilities
No additional information provided in the given text

Electronic Centralised Aircraft Monitoring (ECAM) System

ECAM is a typical electronic/digital aircraft system with BITE capabilities
No additional information provided in the given text

Electronic Flight Instrument System (EFIS)

EFIS is a typical electronic/digital aircraft system with BITE capabilities
No additional information provided in the given text

Engine Indicating and Crew Alerting System (EICAS)

EICAS is a typical electronic/digital aircraft system with BITE capabilities
No additional information provided in the given text

Fly-By-Wire (FBW) Control System

FBW is a typical electronic/digital aircraft system with BITE capabilities
No additional information provided in the given text

Flight Management System (FMS)

FMS is a typical electronic/digital aircraft system with BITE capabilities
No additional information provided in the given text

Global Positioning System (GPS)

GPS is a typical electronic/digital aircraft system with BITE capabilities
No additional information provided in the given text

Inertial Reference System (IRS)

IRS is a typical electronic/digital aircraft system with BITE capabilities
No additional information provided in the given text

Traffic Alert and Collision Avoidance (TCAS)

TCAS is a typical electronic/digital aircraft system with BITE capabilities
No additional information provided in the given text

Built-In Test Equipment (BITE)

BITE is used for self-diagnostic systems troubleshooting, making it easier to troubleshoot complex digital aircraft systems
BITE systems are often used in conjunction with Line Replaceable Units (LRUs)
LRU housing BITE contains self-contained diagnostics for troubleshooting electronic/avionics systems

BITE Systems

Simple BITE systems use a go/no-go red or green LED on the equipment black box or LRU
More complex systems use a multi-character display and monitor more than one LRU
Some BITE can also test the associated wiring
Advanced BITE systems incorporate a centralized monitoring system, flight deck displays, and data transmission capabilities

BITE Information

The Central Maintenance Computer System (CMCS) is an advanced built-in troubleshooting system used by Boeing
The Centralized Fault Display System (CFDS) is an advanced diagnostic system used by Airbus
Commercial airliners may contain several BITE units used to monitor a variety of systems

BITE Philosophy

Most aircraft systems are composed of several individual units called Line Replaceable Units (LRUs)
LRUs are controlled by digital computers and are permanently monitored for safety reasons
The BITE section of a computer is dedicated to monitoring and troubleshooting functions
BITE continuously monitors internal LRU circuits, inputs and outputs, and links between system LRUs
BITE can identify possible failed LRUs, determine if the failure is intermittent or permanent, and provide a snapshot of the system environment at the time of the failure

BITE Function

BITE information is stored in the system BITE memory and sent to a centralized maintenance device
BITE tests can be initiated via this centralized maintenance device, providing a single interface location, easy fault identification, and reduced troubleshooting duration
BITE can be divided into 4 groups: Power Up Test, Cyclic Tests, System Test, and Specific Tests

BITE Groups

Power Up Test: a safety test to ensure compliance with safety objectives, executed only on the ground after any power cut exceeding 200 milliseconds
Cyclic Tests: carried out permanently without disturbing system operation, including watchdog test, RAM test, and data line (ARINC 429) message validity
System Test: performed after system restoration, following replacement of an LRU, to check the integrity of the system
Specific Tests: available for some systems, generating stimuli to various command devices such as actuators or valves

Maintenance Control Display Unit (MCDU)

The MCDU contains a screen for data display, a keyboard, function keys, mode keys, and line keys, used to send commands to the connected systems
The MCDU allows access to the following system components: FM (Flight Management System), ACMS (Aircraft Condition Monitoring System), CMS (Central Maintenance System), SAT (Satellite Communication System), and ATSU (Air Traffic Service Unit)

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Description

This quiz covers the general arrangement of electronic/digital aircraft systems, including Built-In Test Equipment (BITE) and its applications in Aircraft Communications Addressing and Reporting System (ACARS) and Electronic Centralised Aircraft Monitoring System.