DIGITAL FLIGHT
DATA RECORDER

SEE E
FLIGHT 
RECORDER  AIRPLANE 
CENTERLINE 
SEE  F 
VOICE RECORDER 
(REF) 

FWD
AFT PASSENGER CEILING
VOICE AND FLIGHT RECORDER RACK ASSY
E
DIGITAL FLIGHT
DATA RECORDER

DIGITAL FLIGHT DATA RECORDER
F3 F4
3 GUN 001-050,052-205
4 GUN 206-999
Flight Data Recorder System - Component Location Figure 1 (Sheet 3)
E66199
 
 GUN 001-050, 052-999 ú 31-31-00
 ú CONFIG ú 01 Page 4 ú Sep 28/01

A

757 MAINTENANCE MANUAL
 (b)  
INSR switch - enters data set by thumbwheel switch to DFDAU.

 (c)  
EVNT switch - enters an event discrete to DFDAU.

 (d)  
ON-NORM-TEST switch - permits system self confidence test or turn system on for ground test.

 (e)  
SYSTEM light - indicates system fault.

 (f)  
DFDAU, DFDR and FDEP lights - indicates fault within relevant component.

 C. Accelerometer
 (1)  
The flight recorder accelerometer is installed in the left wheel well.

 (2)  
The accelerometer provides vertical, lateral, and longitudinal acceleration signals to the DFDAU. The accelerometer measures vertical acceleration from -3G to +6G. It measures lateral and longitudinal accelerations from -1G to +1G. Excitation for the accelerometer is 28 volts dc supplied by the DFDAU.

 D. Flight Recorder/System Relays.
 (1)  The flight recorder system relays include the left and right ENG START-TO-STOP relays, SYS NO. 2 AIR/GND relay, the FLT REC ADC I/P SWITCHING relay and the FLT REC EFIS I/P switching relay. The ENG START-TO-STOP relays provide AC power to the DFDR and DFDAU when the corresponding engine is running. The SYS NO. 2 AIR/GND relay also provides AC power to the DFDR and DFDAU when the airplane is airborne. The FLT REC ADC I/P SW and EFIS I/P SWITCHING relays select the ADC and EFIS inputs to the DFDAU either from normal or alternate source as selected by the captain.
 E. Digital Flight Data Acquisition Unit
 (1)  
The DFDAU is a microprocessor controlled unit that sequentially receives specific data from various airplane systems and sensors. The acquired data is scaled and formatted into a digital data format. The DFDAU outputs this data to the DFDR for recording.

 (2)  
GUN 001-008, 010, 101 PRE-EO B531006; GUN 009; An ATE connector and fault indicator are located on the front panel of the DFDAU. The ATE connector is provided to connect external test equipment. The DFDAU FAULT indicator comes on to indicate that the DFDAU has detected an internal fault.

 (3)  
GUN 102-999; A READ switch, an ATE connector, fault indicators and a fault display are located on the front panel of the DFDAU. The READ switch is used to display stored fault display. These fault codes are used for bench maintenance. The READ switch is also used to test the fault indicators. ATE connector is provided to connect external test equipment. The DFDAU FAIL and DFDR FAIL lights come on to indicate that the corresponding component has failed. The CAUTION light comes on if the DFDAU input circuits are at fault.
　
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