Air carrier medium large transport altitude deviation overshot 11000' to 10000' during descent.

Attributes
ACN	89019
Time
Date	198806
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : alb
State Reference	NY
Altitude	msl bound lower : 10000 msl bound upper : 11000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zny
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	cruise other descent other
Route In Use	enroute airway : zbw
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 200 flight time total : 9000 flight time type : 800
ASRS Report	89019
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	other

Narrative:

Bos center gave us descent clearance with an altitude and distance crossing restriction. I read the clearance back to center as descent to 10000' MSL by 35 NM from albany, ny. There was also a speed restriction to 250 KTS at 35 NM from alb. I also read that back to center. There was no response from center, so we believed that 10000' was the correct altitude. As we were about to level at 10000', another controller asked us to confirm that we were cleared to 10000'. We told him that we had been cleared to 10000', did he want us to climb back to 11000'? He said yes. We climbed up to 11000' and maintained 250 KTS. Perhaps the controller had not confirmed that I had read back 10000', and not 11000'. I believe that the controller did give the altitude as 10000' initially.

Original NASA ASRS Text

Title: ACR MLG ALT DEVIATION OVERSHOT 11000' TO 10000' DURING DESCENT.

Narrative: BOS CENTER GAVE US DSCNT CLRNC WITH AN ALT AND DISTANCE XING RESTRICTION. I READ THE CLRNC BACK TO CENTER AS DSCNT TO 10000' MSL BY 35 NM FROM ALBANY, NY. THERE WAS ALSO A SPD RESTRICTION TO 250 KTS AT 35 NM FROM ALB. I ALSO READ THAT BACK TO CENTER. THERE WAS NO RESPONSE FROM CENTER, SO WE BELIEVED THAT 10000' WAS THE CORRECT ALT. AS WE WERE ABOUT TO LEVEL AT 10000', ANOTHER CTLR ASKED US TO CONFIRM THAT WE WERE CLRED TO 10000'. WE TOLD HIM THAT WE HAD BEEN CLRED TO 10000', DID HE WANT US TO CLB BACK TO 11000'? HE SAID YES. WE CLBED UP TO 11000' AND MAINTAINED 250 KTS. PERHAPS THE CTLR HAD NOT CONFIRMED THAT I HAD READ BACK 10000', AND NOT 11000'. I BELIEVE THAT THE CTLR DID GIVE THE ALT AS 10000' INITIALLY.

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.