Autoplt failed to capture assigned altitude.

Attributes
ACN	162594
Time
Date	199011
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : hvo
State Reference	WV
Altitude	msl bound lower : 28000 msl bound upper : 28300
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc tower : sea
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	162594
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : overshoot
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Flight had departed dca for bna. Level at FL270, flight was cleared to FL280 and handed off to ind center. Climb commenced on autoplt. FL280 set in altitude window, 'armed' in FMC. 300' prior to level, 'armed' again noted in FMC. Aircraft continued to climb through cleared altitude and failed to level off. Autoplt manually disconnected and acfrt was returned to cleared altitude. The malfunction which prevented the autoplt from leveling the aircraft, whether mechanic or electrical is unknown. Several distrs however, prevented the pilots recognition of the problem. The flight left dca after 2 ground incidents involving controllers at the airport. One of those necessitated an aborted takeoff because of controller error. After departure, the copilot mistakenly entered a wrong navigation frequency for an inbound right. As we were cleared to climb, the F/a had just brought a meal to the copilot. I had set the autoplt for the climb, armed the level off altitude and monitored the FMC annunciations. At 300' prior to required level off altitude every indication was normal. I was distraction, however, by the problem reported and failed to notice the continued climb until approximately 200' above the level off altitude.

Original NASA ASRS Text

Title: AUTOPLT FAILED TO CAPTURE ASSIGNED ALT.

Narrative: FLT HAD DEPARTED DCA FOR BNA. LEVEL AT FL270, FLT WAS CLRED TO FL280 AND HANDED OFF TO IND CTR. CLB COMMENCED ON AUTOPLT. FL280 SET IN ALT WINDOW, 'ARMED' IN FMC. 300' PRIOR TO LEVEL, 'ARMED' AGAIN NOTED IN FMC. ACFT CONTINUED TO CLB THROUGH CLRED ALT AND FAILED TO LEVEL OFF. AUTOPLT MANUALLY DISCONNECTED AND ACFRT WAS RETURNED TO CLRED ALT. THE MALFUNCTION WHICH PREVENTED THE AUTOPLT FROM LEVELING THE ACFT, WHETHER MECH OR ELECTRICAL IS UNKNOWN. SEVERAL DISTRS HOWEVER, PREVENTED THE PLTS RECOGNITION OF THE PROB. THE FLT L DCA AFTER 2 GND INCIDENTS INVOLVING CTLRS AT THE ARPT. ONE OF THOSE NECESSITATED AN ABORTED TKOF BECAUSE OF CTLR ERROR. AFTER DEP, THE COPLT MISTAKENLY ENTERED A WRONG NAV FREQ FOR AN INBND R. AS WE WERE CLRED TO CLB, THE F/A HAD JUST BROUGHT A MEAL TO THE COPLT. I HAD SET THE AUTOPLT FOR THE CLB, ARMED THE LEVEL OFF ALT AND MONITORED THE FMC ANNUNCIATIONS. AT 300' PRIOR TO REQUIRED LEVEL OFF ALT EVERY INDICATION WAS NORMAL. I WAS DISTR, HOWEVER, BY THE PROB RPTED AND FAILED TO NOTICE THE CONTINUED CLB UNTIL APPROX 200' ABOVE THE LEVEL OFF ALT.

Data retrieved from NASA's ASRS site as of July 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.