STUDENT GUIDE FOR T-1A AIRCRAFT SYSTEMS
The avionics system is automatically powered up by placing the two radio master switches,
located on the radio master circuit breaker panel, to the ON position
Electronic Flight Instrument System
The EFIS provides flight information on electronic multicolor displays. The P's EADI and EHSI
receive information from the P's systems and the CP's receive information from the CP's
systems. The EFIS consists of:
Two Display Processor Units (DPU)
Four five-inch Electronic Flight Displays (EFD)
Switches and annunciators
A Multifunction Display (MFD) and joystick
Display Processor Unit
Two DPUs (one for each P) receive and process various data and remote switch inputs and
provide video drive and power for the EFDs. The DPUs are located in the avionics rack. Both
DPUs are interconnected and receive the same data for comparison purposes and are powered up
when the radio master switches are set to the ON position.
Electronic Flight Displays
Four EFDs, two configured as an EADI and two configured as an EHSI, allow the P and CP to
view attitude and heading data on multicolor cathode ray tube displays. Various
navigational/flight information is also displayed.
Electronic Attitude Director Indicator
The EADI has only one basic format which presents attitude, Flight Control System (FCS) mode
annunciations, autopilot engage status, attitude comparator warnings, and decision height set.
Other parameters are displayed as a function of P selection or operational mode.
Attitude Display - Pitch and roll attitude are indicated by the position of the horizon line
(containing the pitch scale) with reference to the aircraft symbol. A red-boxed ATT
annunciation is displayed and flashes above the aircraft symbol if the AHRS sensor fails.
Radio Altitude Display - The green radio altitude display appears automatically when the
aircraft is within the radio altimeter range (2500 feet). The radio altitude display changes in
50-foot increments between full scale and 1000 feet and changes in 10-foot increments below
1000 feet. The radio altitude display is replaced with dashes when radio altitude data is zero or