SDR ASAA2015040911290

Service difficulty report · Fmc · Boeing 737890

Difficulty date: April 9, 2015
Submitted: April 13, 2015
Operation: Air carrier
Aircraft: N596AS
Make and model: Boeing 737890
Aircraft serial: 35688
Aircraft time: 26,404 hours, 8,178 cycles
System (JASC): 3460 · Flight Management Computing Hardware System
Part: Fmc
Condition: Locked
Stage of operation: TX
How discovered: 9
Nature of condition: O
Precautionary procedure: O

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

What was found

FMC LOCKED UP. ALTITUDE SHOWS 50,000 FT SEL SPD, NO VSPD, FD AND LG ALT FLAGS ON BOTH ATTITUDE DISPLAYS. INITIALLY HAD FMC DISAGREE AND FOLLOWED QRH PROCEDURE. FMC DISAGREE WENT AWAY BUT OTHER INDICATIONS REMAINED. ACFT GROUNDED. FOUND THAT MCP HAD LOCKED UP AFTER QRH PROCEDURE. RE-SET CB'S FOR MCP P18-1, D-1, D-2, D-3, D-5 AND E-1. P6-2 B-1, B-3, B-4 AND C-3. MCP OPS NORMAL. PERFORMED MCP TEST 22-11-34-740-801. TESTS OK.