Flight crew of a B767-er descended below assigned altitude during arrival resulting in ATC intervent...

Attributes
ACN	397800
Time
Date	199803
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : atl
State Reference	GA
Altitude	msl bound lower : 10300 msl bound upper : 11000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : atl
Operator	common carrier : air carrier
Make Model Name	B767-300 and 300 ER
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	arrival other enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : flight engineer pilot : commercial pilot : atp
Experience	flight time last 90 days : 150 flight time total : 16000 flight time type : 150
ASRS Report	397800
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 10000 flight time type : 2000
ASRS Report	397799
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Descending and on radar vectors from atl approach control. We understood that we were cleared to descend to 8000 ft. We programmed the MCP to 8000 ft. Passing 10500 ft atlanta approach told us to climb immediately to 11000 ft, which we complied with. Shortly thereafter we were cleared to 8000 ft. We are unsure if we made an altitude mistake or the controller made a mistake. No traffic conflict occurred. If we understood a clearance to 8000 ft in error, it was caused by extremely busy work period and multiple instructions from ATC. Supplemental information from acn 397799: controller couldn't remember giving us 8000 ft. On reflection with all the changes it is possible we misinterpreted the 8000 ft clearance, when given the 180 degree turn, 180 KTS call.

Original NASA ASRS Text

Title: FLC OF A B767-ER DSNDED BELOW ASSIGNED ALT DURING ARR RESULTING IN ATC INTERVENTION.

Narrative: DSNDING AND ON RADAR VECTORS FROM ATL APCH CTL. WE UNDERSTOOD THAT WE WERE CLRED TO DSND TO 8000 FT. WE PROGRAMMED THE MCP TO 8000 FT. PASSING 10500 FT ATLANTA APCH TOLD US TO CLB IMMEDIATELY TO 11000 FT, WHICH WE COMPLIED WITH. SHORTLY THEREAFTER WE WERE CLRED TO 8000 FT. WE ARE UNSURE IF WE MADE AN ALT MISTAKE OR THE CTLR MADE A MISTAKE. NO TFC CONFLICT OCCURRED. IF WE UNDERSTOOD A CLRNC TO 8000 FT IN ERROR, IT WAS CAUSED BY EXTREMELY BUSY WORK PERIOD AND MULTIPLE INSTRUCTIONS FROM ATC. SUPPLEMENTAL INFO FROM ACN 397799: CTLR COULDN'T REMEMBER GIVING US 8000 FT. ON REFLECTION WITH ALL THE CHANGES IT IS POSSIBLE WE MISINTERPRETED THE 8000 FT CLRNC, WHEN GIVEN THE 180 DEG TURN, 180 KTS CALL.

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.

Flight crew of a B767-er descended below assigned altitude during arrival resulting in ATC intervention.