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6) Autotrim inputs identified by the status matrix as TEST or NO COMPUTED DATA are ignored by the SAM. The corresponding autotrim and enable valid discretes are set invalid. The corresponding FCC is not considered as fail unless other monitors are tripped. If enable conditions are met, an AUTOTRIM VALID signal is transmitted to the engaged FCC.
7) Autotrim UP and DOWN (ARM and CONTROL) commands inputs are delayed five seconds. This allows for mode switching and intermittent trim signals. Autotrim commands for the stabilizer trim control modules are output via the autotrim output coincidence monitor. The monitor compares CONTROL and ARM trim commands. The SAM fault ball is set if a difference is detected for longer than two seconds.
8) The SAM monitor sets the SAM fault ball when the following faults are detected: a) Channel code discrete and airplane type code discrete faults (If discrepancy persists for more than 2 seconds). b) Mode coincidence, background, and ARM/CONTROL watchdog faults c) Elevator asymmetry limit actuator and power-up test faults
9) Autotrim commands have priority over Mach/speed commands. Only manual electric and manual trim commands override the autotrim commands. Manual electric trim will not override autotrim when all three FCCs are engaged. Use of manual trim levers while in autotrim mode will cause UNSCHED STAB TRIM annunciation.
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AUTOMATIC STABILIZER TRIM SYSTEM - ADJUSTMENT/TEST
__________________________________________________
1. General_______
A. The paragraphs that follow are an operational test and a system test of the Automatic Stabilizer Trim System. The operational test and the system test require no external test equipment.
(1)
The operational test makes sure that the FCC can command the Stabilizer Trim and Elevator Asymmetry Limit Module (SAM) to move the horizontal stabilizer up or down. It makes sure the FCC-to-SAM interface operates correctly.
(2)
The system test makes sure that the interfaces between equipment items and the automatic stabilizer trim system operate correctly.
TASK 22-22-00-715-011
2. Operational Test - Automatic Stabilizer Trim System___________________________________________________
A. General
(1) This test makes sure that the auto trim mode of the Stabilizer Trim/Elevator Asymmetry Limit Modules (SAMs) operates. The test uses the Maintenance Control Display Panel Ground Test 65-STAB TRIM.
B. References
(1)
22-00-02/201, Autoflight Bite
(2)
24-22-00/201, Electrical Power - Control
(3)
29-11-00/201, Pressurize/Depressurize Main Hydraulic System
C. Access
(1)
Location Zones 119/120 Main Equipment Center 211/212 Control Cabin 312/313 Stabilizer Center Section Compartment
(2)
Access Panel
119BL Main Equipment Center
D. Prepare for Test
S 865-177
(1) Supply electrical power (Ref 24-22-00).
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S 865-001
WARNING: KEEP PERSONS AND EQUIPMENT AWAY FROM ALL CONTROL SURFACES WHEN
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