Electronic Flight Instrument System (EFIS)
Understanding EFIS is crucial for safe, efficient aircraft operation, as it directly affects how pilots interpret and manage flight data, respond to failures, and maintain situational awareness in all conditions.
The Electronic Flight Instrument System (EFIS) replaces traditional mechanical flight instruments with digital displays, integrating key flight data like attitude, heading, airspeed, and altitude into unified, reconfigurable screens. EFIS enhances situational awareness, allows for redundancy in case of failures, and streamlines cockpit layouts with Primary Flight Displays (PFD) and Navigation Displays (ND) as its core components.
Quick Check
Which of the following best describes the core function of an Electronic Flight Instrument System (EFIS)?
Go beyond the textbook.
Explanation
EFIS Components and Architecture
An EFIS installation typically includes several key elements: the Primary Flight Display (PFD), Navigation Display (ND), EFIS control panel, symbol generator, and a remote light sensor. Each pilot (Captain and First Officer) has an independent set, with redundancy built in. The symbol generator is the processing core, creating all the graphical outputs for the displays. In some aircraft, a central backup symbol generator can supply both pilots' displays if one fails, ensuring critical information remains available.
Display Layout and Information Transfer
The PFD presents attitude, airspeed, altitude, heading, and flight mode information in a dynamic color format, following the 'basic T' layout: attitude in the center, airspeed left, altitude right, heading at the lower center. The ND provides navigation and situational data, with selectable modes (MAP, PLAN, VOR, ILS) and adjustable range. If a display fails, information can be transferred to another screen, allowing the crew to maintain access to essential data.
EFIS Control Panel Functions
The control panel lets pilots adjust display brightness, select data sources, set altimeter pressure, choose ND modes and ranges, and input decision heights. It also allows manual switching between redundant systems and resetting alerts. Distinct failure annunciations help crews identify and respond to control panel issues quickly.
Standby Instruments and Redundancy
Despite EFIS reliability, all aircraft retain standby instruments—either traditional or compact electronic units—powered separately and often less conveniently placed. These provide basic flight data if all EFIS displays fail, ensuring continued safe flight even in rare total system outages.
EFIS vs Conventional Instruments
Unlike conventional cockpits with multiple separate gauges, EFIS consolidates information, reduces pilot workload, and improves clarity. The ability to reconfigure displays and cross-check data enhances both operational flexibility and safety.
EFIS Failures and Crew Response
Should an EFIS component fail, pilots can reroute information using the control panel, and redundancy in symbol generators and displays minimizes the impact. Clear failure indications and robust backup systems are integral to safe operation.
Key Points
Exam Traps & Typical Mistakes
Example Exam Questions
Which components are essential parts of a typical EFIS installation?
If a Primary Flight Display (PFD) fails, how is flight information typically restored in an EFIS-equipped aircraft?
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