Air carrier widebody transport altitude excursion.

Attributes
ACN	92106
Time
Date	198807
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : ott
State Reference	MD
Altitude	msl bound lower : 21000 msl bound upper : 22000
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Controlling Facilities	artcc : zdc tower : cno
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	arrival star : star enroute airway : zdc
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 210 flight time total : 15000 flight time type : 450
ASRS Report	92106
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : flight engineer pilot : instrument
Experience	flight time last 90 days : 190 flight time total : 8000 flight time type : 480
ASRS Report	92107
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	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	Pilot Deviation

Narrative:

We were originally cleared to cross 30/5 ott at FL260, which we did. Then ZDC said to continue to FL220. We did this also. We had previously programmed the FMS to arrange descent so as to cross somto at 11000' as nanci 2 arrival calls for. I called and asked ZDC if we were cleared to cross somto at 11000', and he said, 'no, somto at 13000'.' I began programming the FMS and the first officer dialed in 13000' in the autoflt panel. The aircraft was descending through 12600' when ZDC called us and said, 'level off at 21000', you are not cleared to 13000' yet.' we did as he said and explained that we both thought he had cleared us to 13000'. If ZDC actually said expect somto at 13000', then the expect was blocked during his transmission. Ps: incidently, our company has a policy that both pilots must wear headsets below 10000'. It just so happens we both still had our headsets on. Seems we keep them on almost all the time now just for this reason.

Original NASA ASRS Text

Title: ACR WDB ALT EXCURSION.

Narrative: WE WERE ORIGINALLY CLRED TO CROSS 30/5 OTT AT FL260, WHICH WE DID. THEN ZDC SAID TO CONTINUE TO FL220. WE DID THIS ALSO. WE HAD PREVIOUSLY PROGRAMMED THE FMS TO ARRANGE DSCNT SO AS TO CROSS SOMTO AT 11000' AS NANCI 2 ARR CALLS FOR. I CALLED AND ASKED ZDC IF WE WERE CLRED TO CROSS SOMTO AT 11000', AND HE SAID, 'NO, SOMTO AT 13000'.' I BEGAN PROGRAMMING THE FMS AND THE F/O DIALED IN 13000' IN THE AUTOFLT PANEL. THE ACFT WAS DSNDING THROUGH 12600' WHEN ZDC CALLED US AND SAID, 'LEVEL OFF AT 21000', YOU ARE NOT CLRED TO 13000' YET.' WE DID AS HE SAID AND EXPLAINED THAT WE BOTH THOUGHT HE HAD CLRED US TO 13000'. IF ZDC ACTUALLY SAID EXPECT SOMTO AT 13000', THEN THE EXPECT WAS BLOCKED DURING HIS XMISSION. PS: INCIDENTLY, OUR COMPANY HAS A POLICY THAT BOTH PLTS MUST WEAR HEADSETS BELOW 10000'. IT JUST SO HAPPENS WE BOTH STILL HAD OUR HEADSETS ON. SEEMS WE KEEP THEM ON ALMOST ALL THE TIME NOW JUST FOR THIS REASON.

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