Service difficulty report · Autopilot Sys · Boeing 737890

Difficulty date
July 14, 2015
Submitted
July 16, 2015
Operation
Air carrier
Aircraft
N517AS
Make and model
Boeing 737890
Aircraft serial
35197
Aircraft time
25,173 hours, 7,549 cycles
Part
Autopilot Sys
Condition
Malfunctioned
Stage of operation
AP
How discovered
9
Nature of condition
J
Precautionary procedure
O

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

AUTOPILOT "B" DISENGAGED AT APPROXIMATELY 5000' ON ARRIVAL. WOULD NOT RENEGAGE. ACFT GROUNDED. DFCS FAULT REVIEW SHOWED FCC-B AUTOPILOT DISCONNECTS CAUSED BY SMYD-2 FAULT CODE 22-11082 "NO SMYD DATA". ACCOMP. T/S FOR FAULT 22-11082 IAW FIM 22-15, TASK 801, NO FAULTS NOTED. PERFORMED DFCS GROUP NR 10, CURRENT STATUS, NR 11, AUTOPILOT, NR 53 FLAP RIGGING, AND PERFORMED GROUP NR 31, SMYD LRU, TEST AT EACH FLAP POSITION. ALL TESTS PASS. REF SSM 27-32-22, NO OTHER SYS ON SMYD-2 OUTPUT BUS SHOW FAULTS AND SMYD BITE IAW FIM 27-32, TASK 801, SHOWS NO FAULTS. DUE TO HISTORY, REPLACED FCC-B IAW MM 22-11-33. PERFORMED FCC LRU INTERFACE TEST, DFCS GROUP NR 35, IAW MM 22-11-33-400-801, DFCS GROUP NR 49, LAND VERIFY, TEST IAW MM 22-11-00, AND HGS SENSOR TEST FOR FCC/AT IAW HGS SMM 34-36-00, ALL TESTS PASS.