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A B737-200 flight crew climbs out of its assigned altitude of 10000 ft during an autoplt disconnect by captain when aircraft speed activates the speed warning system southwest of iad, va.
| Attributes | |
| ACN | 456520 |
| Time | |
| Date | 199911 |
| Day | Tue |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : iad.airport |
| State Reference | DC |
| Altitude | msl bound lower : 10000 msl bound upper : 10800 |
| Environment | |
| Flight Conditions | VMC |
| Light | Dawn |
| Aircraft 1 | |
| Controlling Facilities | tracon : iad.tracon |
| Operator | common carrier : air carrier |
| Make Model Name | B737-200 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | climbout : intermediate altitude |
| Route In Use | departure : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 200 flight time total : 12500 flight time type : 600 |
| ASRS Report | 456520 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 36 flight time total : 4200 flight time type : 36 |
| ASRS Report | 456319 |
| Events | |
| Anomaly | aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : speed warning |
| Resolutory Action | controller : issued new clearance flight crew : became reoriented flight crew : overrode automation |
| Supplementary | |
| Problem Areas | Aircraft Flight Crew Human Performance Environmental Factor |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
My leg (captain). Brand new first officer (first line trip!). While level at 10000 ft MSL, received 'urgent' ACARS message to call company. They wanted to know why we pushed 1 min late! First officer didn't know how to use ACARS yet, so I responded while flying on autoplt. The autothrottles disengaged for some reason (faulty performance data computer system we found later) and while I was engaged with the ACARS, the aircraft accelerated to 350 KTS. I noticed this just before we got the high speed clacker and immediately retarded the autothrust and autoplt. Aircraft momentarily 'zoomed' to 10800 ft. We were then cleared by center to FL210. Supplemental information from acn 456319: after leveling at 10000 ft, the aircraft continued to accelerate to the barber pole speed and the clacker sounded. The captain disengaged the autoplt and pulled back the thrust levers. The plane started the climb. I called 'altitude' at about 10300 ft. We probably reached 11000 ft before starting a descent back to the assigned altitude. On the way back down, ATC cleared us to a higher altitude. (I suspect that the controller noticed the deviation, but didn't mention it). I believe that the overspd was caused by a performance data computer malfunction, a failure to reduce from a climb to a cruise thrust setting when we leveled at 10000 ft. The climb may have been a result of the captain pulling back on the yoke, or a tendency of the aircraft to pitch up with full thrust applied when the autoplt was disengaged. I was reviewing en route charts. Neither of us noticed that the thrust levers did not come back as they should have when reaching target cruise speed. To prevent recurrence, both crew members should more closely monitor the performance of the autoplt.
Original NASA ASRS Text
Title: A B737-200 FLC CLBS OUT OF ITS ASSIGNED ALT OF 10000 FT DURING AN AUTOPLT DISCONNECT BY CAPT WHEN ACFT SPD ACTIVATES THE SPD WARNING SYS SW OF IAD, VA.
Narrative: MY LEG (CAPT). BRAND NEW FO (FIRST LINE TRIP!). WHILE LEVEL AT 10000 FT MSL, RECEIVED 'URGENT' ACARS MESSAGE TO CALL COMPANY. THEY WANTED TO KNOW WHY WE PUSHED 1 MIN LATE! FO DIDN'T KNOW HOW TO USE ACARS YET, SO I RESPONDED WHILE FLYING ON AUTOPLT. THE AUTOTHROTTLES DISENGAGED FOR SOME REASON (FAULTY PERFORMANCE DATA COMPUTER SYS WE FOUND LATER) AND WHILE I WAS ENGAGED WITH THE ACARS, THE ACFT ACCELERATED TO 350 KTS. I NOTICED THIS JUST BEFORE WE GOT THE HIGH SPD CLACKER AND IMMEDIATELY RETARDED THE AUTOTHRUST AND AUTOPLT. ACFT MOMENTARILY 'ZOOMED' TO 10800 FT. WE WERE THEN CLRED BY CTR TO FL210. SUPPLEMENTAL INFO FROM ACN 456319: AFTER LEVELING AT 10000 FT, THE ACFT CONTINUED TO ACCELERATE TO THE BARBER POLE SPD AND THE CLACKER SOUNDED. THE CAPT DISENGAGED THE AUTOPLT AND PULLED BACK THE THRUST LEVERS. THE PLANE STARTED THE CLB. I CALLED 'ALT' AT ABOUT 10300 FT. WE PROBABLY REACHED 11000 FT BEFORE STARTING A DSCNT BACK TO THE ASSIGNED ALT. ON THE WAY BACK DOWN, ATC CLRED US TO A HIGHER ALT. (I SUSPECT THAT THE CTLR NOTICED THE DEV, BUT DIDN'T MENTION IT). I BELIEVE THAT THE OVERSPD WAS CAUSED BY A PERFORMANCE DATA COMPUTER MALFUNCTION, A FAILURE TO REDUCE FROM A CLB TO A CRUISE THRUST SETTING WHEN WE LEVELED AT 10000 FT. THE CLB MAY HAVE BEEN A RESULT OF THE CAPT PULLING BACK ON THE YOKE, OR A TENDENCY OF THE ACFT TO PITCH UP WITH FULL THRUST APPLIED WHEN THE AUTOPLT WAS DISENGAGED. I WAS REVIEWING ENRTE CHARTS. NEITHER OF US NOTICED THAT THE THRUST LEVERS DID NOT COME BACK AS THEY SHOULD HAVE WHEN REACHING TARGET CRUISE SPD. TO PREVENT RECURRENCE, BOTH CREW MEMBERS SHOULD MORE CLOSELY MONITOR THE PERFORMANCE OF THE AUTOPLT.
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.