🔵✈️ 159. Most Important Features of Electronic Attitude Director Indicator (EADI) on an Airplane 🚁🎞️

Source: FAA-H-8083-31A, Aviation Maintenance Technician Handbook– Airframe, Volume 2, Pag: 10-68

Electronic Attitude Director Indicator (EADI)

The EADI is an advanced version of attitude and electric attitude indicators previously discussed. In addition to displaying the aircraft’s attitude, numerous other situational flight parameters are displayed. 

Most notable are those that relate to instrument approaches and the flight director command bars. Annunciation of active systems, such as the AFCS and navigation systems, is typical.

 

The concept behind an EADI is to put all data related to the flight situation in close proximity for easy observation by the pilot. Most EADIs can be switched between different display screens depending on the preference of the pilot and the phase of flight. EADIs vary from manufacturer to manufacturer and aircraft to aircraft. However, most of the same information is displayed.

EADIs can be housed in a single instrument housing or can be part of an electronic instrument display system. One such system, the electronic flight instrument system (EFIS), uses a cathode ray tube EADI display driven by a signal generator. 

Large-screen glass cockpit displays use LCD technology to display EADI information as part of an entire situational display directly in front of the pilot in the middle of the instrument panel. 

Regardless, the EADI is the primary flight instrument used for aircraft attitude information during instrument flying and especially during instrument approaches. It is almost always accompanied by an electronic horizontal situation indicator (EHSI) located just below it in the display panel. 

EADI Component or Feature	Description of Functionality	Display Technology Used	Associated Flight Systems	Physical Location in Cockpit	Key Advantages
Attitude Display	Displays the aircraft's pitch and roll attitude as the primary flight instrument for instrument flying and approaches.	CRT or LCD	EFIS, AFCS, and navigation systems	Directly in front of the pilot in the center of the instrument panel, positioned above the EHSI.	Consolidates all situational flight data in close proximity for easy observation.
Instrument Approach Data	Displays flight parameters and guidance specifically related to instrument approaches.	CRT or LCD	Navigation systems	Integrated into the EADI display screen within the instrument panel.	Enables easier observation of critical approach data during instrument flight.
Flight Director Command Bars	Visual guidance bars providing steering commands to the pilot based on programmed flight paths.	CRT or LCD	AFCS (Automatic Flight Control System)	Integrated into the EADI display screen.	Allows for integrated annunciation of active systems alongside attitude data.
CRT-based EFIS Display	A cathode ray tube implementation of the EADI driven by a signal generator for visual output.	Cathode Ray Tube (CRT)	Electronic Flight Instrument System (EFIS)	Housed in a single instrument housing or as part of a centralized instrument display system.	Provides an advanced digital version of traditional electric attitude indicators.
Large-screen Glass Cockpit EADI	Modern implementation using LCD technology to display EADI information as part of a comprehensive situational display.	Liquid Crystal Display (LCD)	Electronic Flight Instrument System (EFIS)	Directly in front of the pilot in the center of the instrument panel.	Scalable for large-screen situational displays and improved clarity.