SDR ASAA2013052194871

Service difficulty report · Computer · Boeing 737890

Difficulty date: May 21, 2013
Submitted: May 25, 2013
Operation: Air carrier
Aircraft: N508AS
Make and model: Boeing 737890
Aircraft serial: 35691
Aircraft time: 18,422 hours, 5,762 cycles
System (JASC): 3460 · Flight Management Computing Hardware System
Part: Computer
Condition: Malfunctioned
Stage of operation: CL
How discovered: O
Nature of condition: N
Precautionary procedure: O

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

What was found

DURING CLIMBOUT WITH NAV PITCH MODE, AN ALTITUDE WAS SELECTED AND VERIFIED IN THE ALTITUDE DISPLAY BY THE PNF (PILOT NOT FLYING). WITHIN 1 MINUTE THE ALTITUDE DISPLAY CHANGED ON ITS OWN TO 50,000 AND THE ALERT HORN SOUNDED. THIS HAPPENED 3 TIMES ON THE CLIMBOUT. ACFT GROUNDED. REF AMM FIM TASK 34-61-801 FMC BITE NO FAULTS FOUND. ALSO PERFORMED FIM TASK 34-21-801 ADIRS BITE, NO FAULTS FOUND. ACFT OK FOR SERVICE.