Air carrier large transport in automatic mode failed to capture and overshot altitude.

Attributes
ACN	87569
Time
Date	198805
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : bos
State Reference	MA
Altitude	msl bound lower : 31000 msl bound upper : 31400
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zbw artcc : zny
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude
Route In Use	enroute airway : zbw
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 18000 flight time type : 65
ASRS Report	87569
Person 2
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : overshoot non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

Aircraft climbed through assigned altitude, 31000' (FL310). Stopped climb manually at 31400'. Suspect FMC computer malfunction (after xchking with left, center and right irus and left, center and right automatic pilots). Continued to bwi manually flown with computer back up. Callback conversation with reporter revealed the following: this was a new aircraft. The company had only had them 6 months and the pilot was also fairly new on the aircraft. Said this was the first occurrence his company had and was possible he inadvertently activated something he had not intended to activate and deactivated capture mode.

Original NASA ASRS Text

Title: ACR LGT IN AUTO MODE FAILED TO CAPTURE AND OVERSHOT ALT.

Narrative: ACFT CLBED THROUGH ASSIGNED ALT, 31000' (FL310). STOPPED CLB MANUALLY AT 31400'. SUSPECT FMC COMPUTER MALFUNCTION (AFTER XCHKING WITH LEFT, CENTER AND RIGHT IRUS AND LEFT, CENTER AND RIGHT AUTO PLTS). CONTINUED TO BWI MANUALLY FLOWN WITH COMPUTER BACK UP. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: THIS WAS A NEW ACFT. THE COMPANY HAD ONLY HAD THEM 6 MONTHS AND THE PLT WAS ALSO FAIRLY NEW ON THE ACFT. SAID THIS WAS THE FIRST OCCURRENCE HIS COMPANY HAD AND WAS POSSIBLE HE INADVERTENTLY ACTIVATED SOMETHING HE HAD NOT INTENDED TO ACTIVATE AND DEACTIVATED CAPTURE MODE.

Data retrieved from NASA's ASRS site as of August 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.