Narrative:

I was the PNF. During climb out at around FL270-FL280, I heard the trim operating faster than it should and noticed that the airspeed had decreased to approximately 10 KIAS above the clean minimum manual bug (the autoplt was engaged and was in the vertical speed mode). I said that the airspeed was getting low and simultaneously with the captain disengaged the autoplt and lowered the nose while telling ZAB that we needed to stop the climb and perhaps descend to investigate a problem. ZAB said ok and to advise them as needed. The captain continued to fly the plane and had disengaged the autothrottles and advanced the power. We descended slightly until the airspeed had been regained then continued our climb and the remainder of the flight uneventfully. Callback conversation with reporter revealed the following information: reporter indicated that the PF was a management pilot with very little flight time in recent months. He said that vertical speed was the mode in use and that this is unusual to use it at the altitude reported under normal procedures. The autoflt system was trying to maintain the requested vertical speed and could not without sacrificing airspeed. The reporter faults himself for not catching the reducing airspeed sooner. The company involved has reviewed this report and is considering making a change in the flying proficiency requirements for their personnel who do not routinely operate on a scheduled basis.

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Original NASA ASRS Text

Title: ACR CREW ALLOWS AIRSPD TO GET TOO LOW DURING CLB.

Narrative: I WAS THE PNF. DURING CLBOUT AT AROUND FL270-FL280, I HEARD THE TRIM OPERATING FASTER THAN IT SHOULD AND NOTICED THAT THE AIRSPD HAD DECREASED TO APPROX 10 KIAS ABOVE THE CLEAN MINIMUM MANUAL BUG (THE AUTOPLT WAS ENGAGED AND WAS IN THE VERT SPD MODE). I SAID THAT THE AIRSPD WAS GETTING LOW AND SIMULTANEOUSLY WITH THE CAPT DISENGAGED THE AUTOPLT AND LOWERED THE NOSE WHILE TELLING ZAB THAT WE NEEDED TO STOP THE CLB AND PERHAPS DSND TO INVESTIGATE A PROB. ZAB SAID OK AND TO ADVISE THEM AS NEEDED. THE CAPT CONTINUED TO FLY THE PLANE AND HAD DISENGAGED THE AUTOTHROTTLES AND ADVANCED THE PWR. WE DSNDED SLIGHTLY UNTIL THE AIRSPD HAD BEEN REGAINED THEN CONTINUED OUR CLB AND THE REMAINDER OF THE FLT UNEVENTFULLY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR INDICATED THAT THE PF WAS A MGMNT PLT WITH VERY LITTLE FLT TIME IN RECENT MONTHS. HE SAID THAT VERT SPD WAS THE MODE IN USE AND THAT THIS IS UNUSUAL TO USE IT AT THE ALT RPTED UNDER NORMAL PROCS. THE AUTOFLT SYS WAS TRYING TO MAINTAIN THE REQUESTED VERT SPD AND COULD NOT WITHOUT SACRIFICING AIRSPD. THE RPTR FAULTS HIMSELF FOR NOT CATCHING THE REDUCING AIRSPD SOONER. THE COMPANY INVOLVED HAS REVIEWED THIS RPT AND IS CONSIDERING MAKING A CHANGE IN THE FLYING PROFICIENCY REQUIREMENTS FOR THEIR PERSONNEL WHO DO NOT ROUTINELY OPERATE ON A SCHEDULED BASIS.

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.