SDR ASAA2019080230273

Service difficulty report · Autopilot Sys · Boeing 737890

Difficulty date: July 31, 2019
Submitted: August 3, 2019
Operation: Air carrier
Aircraft: N557AS
Make and model: Boeing 737890
Aircraft serial: 35176
Aircraft time: 50,406 hours, 14,747 cycles
System (JASC): 2210 · Autopilot System
Part: Autopilot Sys
Condition: Malfunctioned
Stage of operation: AP
How discovered: O
Nature of condition: F
Precautionary procedure: O

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

What was found

WHILE ATTEMPTING A HGS AIII AUTOLAND, AUTOPILOT DISCONNECTED AT ABOUT 2100' MSL AND ABOUT 6 MILES ON FINAL APPROACH. AMBER "NO AIII" ILLUMINATED FOR ABOUT FIVE SECONDS SHORTLY BEFORE THE DISCONNECT BUT HAD RETURNED TO GREEN "AIII" . NEVER GOT AN "APCH WARN". GROUNDED - YES. TESTS AND LAND VERIFY TEST, ALL TESTS PASS WITH NO FAULTS. REF B737-800 FIM 22-11 TASK 801, FIM 22-14 TASK 801, AND FIM 22-11 TASK 805. ACCOMPLISHED HGS SYSTEM TEST WITH NO FAULTS NOTED, REF SMM 34-36-00.