Electronic Instrument Systems (PDF) - Aviation Australia

Okay, here is the converted markdown format of the attached document. # Aviation AUSTRALIA ## Electronic Instrument Systems (5.1) ### Learning Objectives * 5.1.1 Describe typical arrangements of electronic instrument systems (Level 2). * 5.1.2 Describe a typical cockpit layout of electronic...

Okay, here is the converted markdown format of the attached document. # Aviation AUSTRALIA ## Electronic Instrument Systems (5.1) ### Learning Objectives * 5.1.1 Describe typical arrangements of electronic instrument systems (Level 2). * 5.1.2 Describe a typical cockpit layout of electronic instrument systems (Level 2). ## Conventions and Development ### Early Instrument Systems In the early days of aviation, aircraft had a clock (optional) and a compass, which was acceptable for flights in daytime in clear weather. Next came an altimeter, then a simple attitude instrument. :::info The image is of an old aircraft cockpit with a variety of analogue instruments, including a clock, compass, and altimeter. There are also visible labels for "SMOKING PROHIBITED" and a speed limit of "NOT EXCEED 130 M.P.H." ::: **Early aircraft basic instrument cluster** As more instruments became available, the individuals involved laid out the instrument panel as they wanted, squeezing instruments in where they could. This became a problem for pilots who flew more than one type of aircraft as they had to relearn the instrument position before the flight. :::info The image shows a black and white picture from inside the cockpit of an old airplane. It shows many analogue dials and instruments. ::: After 1950 most aircraft cockpit instrument systems were arranged in the **Basic T configuration**. Every aircraft had an Airspeed Indicator (ASI), Attitude indicator (AI) and altimeter in a row, which made the information required in an emergency immediately identifiable. With the compass below these instruments, the pilot could now fly in the dark or in poor weather without becoming disoriented. :::info The image shows a close-up view of the "Basic T" configuration of aircraft instruments, including the ASI, AI, and altimeter. Additional cockpit instruments are also visible. ::: Additions to the Basic T included a turn coordinator (or a turn and slip indicator) and a Vertical Speed Indicator (VSI) at the bottom left and bottom right respectively. These were added to give the pilot more accurate immediate information. Due to the difficulty in seeing a 1° bank on an ADI, the pilot would notice a gradual drift in heading and have to correct by banking in the other direction. The turn co-ordinator now shows an accurate wing level position and therefore fewer corrections are required. :::info The image displays a "Basic six instrument cluster" featuring the ASI, AI, altimeter, turn coordinator, and VSI. ::: Larger aircraft such as the 747 Classic (early model) use the same Basic T configuration, except with the addition of a rad alt, standby instruments and special features on the standard instruments such as ILS, VOR guidance indicators and a rising runway. In these cases, the additional functionality has resulted in the Artificial Horizon and Directional Gyro being renamed to the Attitude Direction Indicator (ADI) and the Horizontal Situation Indicator (HSI) respectively. Standby instruments and engine instrumentation are conventionally placed in the center of the panel, one set being easily readable by both pilots. ## Electronic Instrument Display Technology Types of electronic displays commonly used in aircraft: * Light-emitting diodes * Liquid crystal displays. Some older displays may still use cathode ray tube technology however this technology is becoming rarer due to the reliability, physical size, and service life of this technology. The signals produced by sensors, and the digital signals transmitted over a digital data bus, are incapable of generating a display on a screen. The signals simply convey information about certain parameters. Display units must be supported by processors and electronic devices to interpret the data provided by sensors and avionics data buses. Then, they generate signals to produce information on the screen. :::info The picture is of a cockpit with two LCD screens. ::: ## Arrangements of Electronic Instrument Systems ### Electronic Flight Instruments System The purpose of the EFIS display system is to provide the flight crew with the information required to operate the aircraft. Instead of using large numbers of analogue instruments, the EFIS is used to display all the primary aircraft operational information on display screens. This reduces the number of devices that aircrew have to scan and also reduces the instrument clutter that is common in analogue instrument-based cockpits. It also provides a maintenance advantage as fewer mechanical instruments are required for the system, which increases reliability and serviceability. A typical EFIS system consists of four interchangeable displays: an EADI (Electronic Attitude Director Indicator) and EHSI (Electronic Horizontal Situation indicator) each for the Captain and First Officer, three symbol generators, two control panels and two source selection panels. A third (centre) symbol generator may be incorporated if a primary symbol generator fails. In aircraft with an avionics digital data bus and multifunction displays, the EFIS displays directly in front of the pilots are not restricted to only displaying EADI and EHSI information. The EFIS typically contains four large colour displays – two PFDs (Primary Flight Displays) and two MFDS (Multifunction Displays) or (NDs) Navigation Displays. The modern display systems include the following advantages: * Large, uncluttered displays enhance crew efficiency and situational awareness. * Versatile formats allow displays to be used interchangeably as a PFD (Primary Flight Display), MFD (Multifunction Display) or EICAS/ECAM display. * PFDs include attitude, air data, navigation references and Traffic Collision Avoidance System (TCAS) resolution advisories. * MFDs include navigation maps, weather radar, TCAS traffic and maintenance data. Operation can be broken down into two distinct functions: * Electronic Flight Instruments System (EFIS) – PFD and MFD * Engine Indication and Crew Alerting System (EICAS – Boeing) or Electronic Centralised Aircraft Monitoring (ECAM – Airbus). The two central displays are commonly aligned to either EICAS or ECAM systems, but all six displays can be interchangeable depending on the aircraft. In the following example, both cockpit images are of the same single engine aircraft. The top image was taken before installation of the glass cockpit. In the lower image the number if instruments have been significantly reduced by the modification but the same information is displayed. :::info The images show a single engine aircraft's cockpit before and after a "glass cockpit" modification. The 'before' image shows conventional instruments, while the 'after' image shows a significantly reduced number of instruments with newer LCD style displays. ::: Even the latest aircraft models with the most up-to-date systems incorporate the Basic T configuration system to minimise training times and make finding an instrument intuitive. :::info The image is a close-up of a modern aircraft display screen, showing an integrated EADI and EHSI. ::: ### EADI and EHSI The ability to manufacture display screens in the required size resolution and reliability improvements resulted in the mechanical ADI and HSI being replaced by the Electronic Attitude Direction Indicator (EADI) and Electronic Horizontal Situation Indicator (EHSI). :::info The image is a close-up shot of 2 electronic displays, one above the other, and the bottom one displaying the EHSI, while the top one displays the EADI. ::: ### PFD and ND It was not long before manufacturers realised the full potential of electronic instrumentation. The EADI was integrated with airspeed (IAS) information (in tape form) with stall and overspeed visual warnings, altitude and vertical speed information (in tape form), along with autopilot and other annunciations. All information required to fly the aircraft is supplied on one screen. The name was changed to the more appropriate Primary Flying Display (PFD). :::info The image is a close up showing the Primary Flight Display (PFD) and Navigation Display (ND) for a Boeing aircraft. ::: The EHSI was integrated with ADF, ILS, VOR and flight plan MAP information, colour coded for easier and more instantaneous mode recognition; aircraft speeds (GS and TAS) and heading/track information in digital format, and annunciation of which NAV equipment is supplying the data. All information required to navigate the aircraft is supplied on one screen. Selectable alternative configurations enable the pilot to view the display in either full rose, with variable ranging rings indicated. The name was changed to the more appropriate Navigation Display (ND). | | | | :------------- | :------------------ | | **ADI** | | | **ASI** | | | **Mach Meter** | | | **Compass** | | | **Altimeter** | | | **VSI** | | **Auto-flight Annunciators** :::info The image shows a conventional cockpit instrument panel replaced by a PFD. ::: **Conventional instruments replaced by the PFD** The PFD replaces many analogue instruments: * Attitude Director Indicator (ADI), including Flight Director (FD) * Air Speed Indicator (ASI) * Machmeter * Compass or Directional Gyro (DG), true or magnetic * Altimeter * Vertical Speed lndicator(VSI). As well as these basics, the PFD now displays other indications: * Autopilot mode information * Track * Flight plan (Speed or Mach, Track) * Traffic collision avoidance system (TCAS) information * Pressure of the day (1013.25 $mb = 1013.25 hPa = 29.92$ inHg). :::info The two images show examples of Airbus PFD and ND displays ::: The ND can be integrated with terrain information from a worldwide mesh terrain database, (EGPWS), with weather radar information (including local ground mapping) and traffic information (ACAS/TCAS). In the case of the latter, the PFD and ND provide Resolution Advisories in the event of a collision threat. :::info The image shows the ND display for a commercial aircraft displaying terrain and weather data. ::: :::info The top image shows the EADI and EHSI on a Boeing 737, among Conventional Instrumentation The bottom image shows a PFD and ND on a Boeing 777 ::: ## Cockpit Layout of Electronic Instrument Systems ### The Boeing System The Boeing system uses the Engine Indicating and Crew Alert System (EICAS) to provide airframe and engine data. The primary and secondary (upper and lower) screens display primary and secondary engine data, respectively, and indicate visual cautions, warnings and memos regarding aircraft system status. System synoptics are also displayed on these screens. More information on the EFIS and EICAS is provided in Module 5 Topic 15. :::info The image is a diagram of a Boeing instrument panel layout with EFIS and EICAS displays, highlighting CAPTAIN'S DISPLAY TRANSFER PANEL, LEFT EFIS CONTROL PANEL, EICAS DISPLAY SELECT PANEL, CAPTAIN'S PRIMARY FLIGHT DISPLAY, CAPTAIN'S NAVIGATION DISPLAY, MAIN EICAS, AUX EICAS, 1ST OFFCR NAVIGATION DISPLAY, 1ST OFFCR PRIMARY FLIGHT DISPLAY and FIRST OFFICER'S POSITION ::: ### The Airbus System The Airbus flight deck display system uses the Electronic Centralised Aircraft Monitor System (ECAM) to provide the engine, system and synoptic information. The primary and secondary (upper and lower) screens display primary and secondary engine data, respectively, and indicate visual cautions, warnings and memos regarding aircraft system status. System synoptics are also displayed on these screens. :::info The image is a diagram of the Airbus EFIS instrument display layout, highlighting the position of the SIDESTICK CONTROLLER, DISPLAYS CONTROL, AUTOPILOT CONTROL, CONROL, PRIMARY FLIGHT DISPLAY, NAV DISPLAY, ELECTRONIC CENTRALIZED AIRCRAFT MONITOR SYSTEM (ECAM), MULTI-PURPOSE CONTROL & DISPLAY UNIT, FIRST OFFICER (Co-Pilot) and CAPTAIN ::: :::info The image shows the Airbus - Electronic Centralised Aircraft Monitor System (ECAM) primary and secondary displays ::: More information on the EFIS and ECAM is provided in Module 5 Topic 15. | | | | :------- | :---- | | ECAM | UPPER | | DISPLAY | | | T.O | | | CONFIG | | | EMER | | | CANC | | | | OFF | | BRT | | | AFT CABIN | DOOR | | | | **ECAM control panel** ### Engine Indicating and Crew Alert System (Boeing) The EICAS system does not incorporate separate symbology generators. Symbol generation is performed by the EICAS computers. :::info The diagram provides a Simplified diagram of Boeing 757 EICAS, highlighting AIRCRAFT SYSTEM SENSORS, ENGINE SENSORS, MAINTENANCE PANEL, WARNINGS CAUTIONS ADVISORIES, ENGINE PRIMARY DISPLAYS, TOP PILOT'S DISPLAY SELECT PANEL, LEFT EICAS COMPUTER, CENTRAL DISPLAY UNITS, RIGHT EICAS COMPUTER, DISPLAY SWITCHING MODULE and SECONDARY DISPLAYS STATUS DISPLAY OR MAINTENANCE DISPLAYS ::: **Boeing ElCAS system** EICAS provides comprehensive monitoring of aircraft systems, dispatch information, storage of maintenance-related data, colour-coded displays and alert messages.