Altitude deviation.

Attributes
ACN	296150
Time
Date	199409
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : atl
State Reference	GA
Altitude	msl bound lower : 28600 msl bound upper : 29000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : ztl
Operator	common carrier : air carrier
Make Model Name	B727-200
Operating Under FAR Part	Part 121
Flight Phase	descent other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 17400 flight time type : 8000
ASRS Report	296150
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude altitude deviation : overshoot non adherence : clearance
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : became reoriented other
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

Center had cleared us from FL330 down to FL290. Just before reaching 29000 ft, ATC cleared us direct to a different NAVAID. While one was looking up the frequency and the other pilot was setting in the course, the aircraft went 400 ft below our assigned altitude of FL290. The controller on frequency 135.37 asked us to check our altitude. I answered 'we are correcting' and nothing else was said. It would have been helpful if the controller had given us a heading towards the NAVAID, that way we would have known which heading to turn to and could have taken more time in looking up the frequency and setting it in. This would have let the PF split his attention between less things and may have caught the altitude sooner. Contributing factor was malfunctioning autoplt altitude hold mode, of which crew was unaware of until this occurrence. Callback conversation with reporter revealed the following information: the reporter flies as first officer on the B-727-200 for an 'upstart' air carrier. He has flown as captain on the B-727 for other carriers. The primary problem was the communications distraction, a routing change with no initial vector to help the flight crew. It was 'very busy at that time.' the flight crew found out about the altitude hold autoplt problem in the middle of the course change.

Original NASA ASRS Text

Title: ALTDEV.

Narrative: CTR HAD CLRED US FROM FL330 DOWN TO FL290. JUST BEFORE REACHING 29000 FT, ATC CLRED US DIRECT TO A DIFFERENT NAVAID. WHILE ONE WAS LOOKING UP THE FREQ AND THE OTHER PLT WAS SETTING IN THE COURSE, THE ACFT WENT 400 FT BELOW OUR ASSIGNED ALT OF FL290. THE CTLR ON FREQ 135.37 ASKED US TO CHK OUR ALT. I ANSWERED 'WE ARE CORRECTING' AND NOTHING ELSE WAS SAID. IT WOULD HAVE BEEN HELPFUL IF THE CTLR HAD GIVEN US A HDG TOWARDS THE NAVAID, THAT WAY WE WOULD HAVE KNOWN WHICH HDG TO TURN TO AND COULD HAVE TAKEN MORE TIME IN LOOKING UP THE FREQ AND SETTING IT IN. THIS WOULD HAVE LET THE PF SPLIT HIS ATTN BTWN LESS THINGS AND MAY HAVE CAUGHT THE ALT SOONER. CONTRIBUTING FACTOR WAS MALFUNCTIONING AUTOPLT ALT HOLD MODE, OF WHICH CREW WAS UNAWARE OF UNTIL THIS OCCURRENCE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR FLIES AS FO ON THE B-727-200 FOR AN 'UPSTART' ACR. HE HAS FLOWN AS CAPT ON THE B-727 FOR OTHER CARRIERS. THE PRIMARY PROB WAS THE COMS DISTR, A ROUTING CHANGE WITH NO INITIAL VECTOR TO HELP THE FLC. IT WAS 'VERY BUSY AT THAT TIME.' THE FLC FOUND OUT ABOUT THE ALT HOLD AUTOPLT PROB IN THE MIDDLE OF THE COURSE CHANGE.

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.