Electronic Instrument Systems Quiz

Electronic Instrument Systems (5.1)

• Learning objectives include describing typical electronic instrument system arrangements and cockpit layouts.

Early Instrument Systems

• Early aircraft had basic instruments like clocks (optional), compasses, altimeters, and a simple attitude instrument.
• Early instrument panel layouts were often inefficient, with pilots needing to relearn layouts for different aircraft types.

NY2 Husky First Blind Flying Cockpit

• Post-1950 aircraft instrument systems were often arranged in a "Basic T" configuration.
• This configuration placed essential instruments like Airspeed Indicator (ASI), Attitude indicator (Al), and altimeter in a row.
• The compass was located below these instruments.
• This arrangement improved situational awareness during poor visibility conditions.

Basic Six Instrument Cluster

• Larger aircraft, like the 747 classic, use a similar Basic T configuration.
• These configurations include additional instruments like standby instruments and special functions.
• These aircraft also often have an Attitude Direction Indicator (ADI) and a Horizontal Situation Indicator (HSI).
• Standby instruments and engine instrumentation are centrally located for ease of use by both pilots.

Electronic Instrument Display Technology

• Common electronic displays types include light-emitting diodes (LEDs) and Liquid Crystal Displays (LCDs).
• Older systems may utilize Cathode Ray Tube (CRT) technology, but this technology is less common due to its size and reliability.
• Electronic displays require processors and data buses to convert sensor data and information into visualizations.

Electronic Flight Instrument System (EFIS)

• EFIS displays all critical flight information on screens instead of traditional instruments.
• This reduces the number of items pilots need to monitor, improving situational awareness.
• EFIS systems are generally more reliable than mechanical systems.
• A cockpit with an EFIS will have interchangeable displays like EADI (Electronic Attitude Director Indicator) or EHSI (Electronic Horizontal Situation Indicator).

PFD and ND

• PFD (Primary Flight Display) integrates speed, warnings, altitude with essential flight information on a single screen.
• ND (Navigation Display) provides navigation information (ADF, ILS, VOR, flight plan map) and speed/headings in a similar fashion.

Conventional Instruments Replaced by PFD

• The PFD replaces many traditional instruments like the Attitude Director Indicator (ADI), Air Speed Indicator (ASI), Machmeter, Compass/Directional Gyro, Altimeter, and Vertical Speed Indicator (VSI), allowing for all the data to be displayed in a single location.
• Provides information such as autopilot mode, flight plans, traffic avoidance systems and the pressure of the day.

Multifunction Displays and Digital Data Bus

• Multifunction Displays (MFDs) display information from many aircraft systems on a single screen.
• Digital data buses (or networks) connect different parts of the aircraft electronically to send and receive data.
• Data buses are typically duplicated for redundancy in case one component fails.

Symbol Generators

• Symbol generators process sensor information and communicate with displays.
• They act as the central processing unit for the display screens.
• Multiple symbol generators may be present for redundancy measures.

Basic Operation of Aircraft Display Systems

• Symbol generators receive data from the data bus and transmit it to display units.
• Displays use multiple data channels for redundancy.
• Display systems may use dedicated display buses.

Display System Schematic

• Two main types of data (raster and stroke) are displayed.
• Raster data is used for displaying continuously measured data (information from the radar).
• Stroke data is for displaying discrete elements (like circles or lines on the display).

Electronic Centralised Aircraft Monitoring (ECAM)

• ECAM uses a central system to display information from many different aircraft subsystems.
• ECAM is typically located in the center of the instrument panel and can be used to display information for both pilots.
• Newer systems may allow the display to be selected in place of an EFIS display.

ECAM Control Panel

• ECAM panels use push-button and knob controls to select display functions.
• Maintenance panels are part of the system for tests and checks.

Engine Indicating and Crew Alert System (Boeing)

• EICAS performs engine monitoring and data display for pilots.
• Symbology generators are not separate entities in EICAS but performed by the computer systems.

Auxiliary EICAS Display

• The lower display shows secondary data and parameters.
• Displays change depending on the selected function and the aircraft type.
• The lower display in modern systems can also be used for status pages, synoptics, or maintenance pages.