(b)
The subsystem test shortens BITE testing by approximately 2 minutes. However, only the selected subsystem is tested and test on the nonvolatile RAM section is omitted.
(c)
To select the on-ground system or subsystem test, on the PSEU, enter appropriate CHANNEL SELECT code listed below:
CHANNEL SELECT______________ SUBSYSTEM 500 Cargo Door Control System 501 All Thrust Reverser Systems 502 Door System 503 Landing Gear System No. 1 504 Landing Gear System No. 2 505 All Systems
Select any code other than 500-505 for complete system test.
(d) Pressing the VERIFY switch on the BITE panel starts testing. Test is inhibited when the airplane is in the air mode. Tests can be cancelled at any time by pressing the PRESS/TEST switch.
32-09-03
ALL ú ú 04 Page 13 ú Mar 15/87
A
757
MAINTENANCE MANUAL
(e)
The readout display flashes code CCC to indicate test in progress. Complete system test takes approximately 4 minutes (2 minutes for subsystem test). Completion of a successful system test is indicated by code 999. If a fault is detected, a three digit code representing the faulty element is displayed. A faulty sensor or card is indicated by illumination of the SENSOR or CARD light. Incorrect target position is indicated by the TARGET light. Fault codes are listed on the front panel. Additional fault codes following the first can be obtained by repeatedly pressing the VERIFY switch until code 999 is displayed. All panel indicators are automatically turned off 60 seconds after turn on.
(f)
During an on-ground system test, BITE functions are verified by performing a PROM (programmable-read-only-memory) checksum test, a RAM (random-access-memory) read/write test, a nonvolatile RAM read/write test, and a CPU (central processing unit) self-test. All circuits in the PSEU are functionally tested. This includes switching each output driver at least once to the on and off states. This may cause flickering lights, nuisance EICAS messages in the flight deck, the "air" simulation of the air ground system, and possible electrical power bus switching.
(12)
Target position reasonableness test
(a)
The target position reasonableness test is performed as part of the in-flight or on-ground system verify test. Target discrepancies are checked by comparing groups of sensors for reasonableness of position. Groups of sensors that should be in comparable target mode (target near or target far) are given in Table 3. During "In-Flight BITE", faults are stored in memory. During "Ground BITE" (system verify test), a fault will cause the TARGET light to illuminate.
32-09-03
ALL ú ú 02 Page 14 ú Mar 15/87
A
757
MAINTENANCE MANUAL
~.............................................................................. | Table 3 | | Target Position Reasonableness Test | ................................................................................ | | | Sensor Status *[1] | BITE Test | | | ........................................................ | Group | Sub-System | Sensor Target | Sensor Target | | | | No. | & Mode | Near/Discrete | Near/Discrete | In-Flt | Ground | | | | Input Low *[2] | Input High *[2] | | | ................................................................................
| | | | | | |
| 1 | Door System | S10083, S10085, | | Yes | No |
| | Mode: | S10086, S10088, | | | |
| | Doors Closed | S10090-S10097 | | | |
| | | | | | |
| 2 | Landing Gear | S10057, S10061, | S10238-S10240, | Yes | Yes |
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：757 AMM 飞机维护手册 起落架 CHAPTER 32 - LANDING GEAR 1(50)
