Service difficulty report · Unknown · Boeing 737890

Difficulty date
July 29, 2018
Submitted
August 1, 2018
Operation
Air carrier
Aircraft
N508AS
Make and model
Boeing 737890
Aircraft serial
35691
Aircraft time
38,448 hours, 11,562 cycles
Part
Unknown
Condition
Malfunctioned
Location
Autopilot Sys
Stage of operation
LD
How discovered
O
Nature of condition
J
Precautionary procedure
K

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

What was found

AUTOLAND UNSATISFACTORY. AT APPROX 70 FEET AGL, AUTOPILOT COMMENCED A LEFT BANK, FOLLOWED QUICKLY BY AN APPCH WARNING. GROUNDED - YES. ACCOMPLISHED LLM MAINTENANCE PRACTICES FOR LLM SPECIAL CONDITION. INBOUND CONDITION RELATED TO AUTOLAND PER AMM 22-00-01-730-807. DFCS GROUP 20 (FAULT REVIEW) SHOWED NO RELEVANT FAULTS LOGGED AND DFCS GROUP 49 (LAND VERIFY) TEST PASSED WITH NO FAULTS. HGS FAULT REVIEW PER HGS SMM 34-36-00 SHOWED AN APPROACH WARNING LOGGED ON LEG 11 WITH CAUSE "XTK RATE EXCEED" AND TWO APPROACH WARNINGS LOGGED ON LEG 17 WITH CAUSE "AIRSPEED EXCEED" AND "GLIDESLOPE EXCEED" AND AN ASSOCIATED ROLLOUT CAUTION FAULT WITH CAUSE "ILS ANOMALY DETECTED". ALL FAULTS HAVE EXTERNAL CAUSES. SUSPECT AUTOLAND DEVIATION RELATED TO ILS ANOMALY DETECTED BY HGS. ACCOMPLISHED MAINTENANCE TEST FOR MEL 22-99C PER AMM 22-00-01-730-803 - ALL TESTS PASS.