Flight crew controller misunderstanding about the altitude cleared to.

Attributes
ACN	133683
Time
Date	199001
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : svm airport : dtw
State Reference	MI
Altitude	msl bound lower : 10000 msl bound upper : 12000
Environment
Flight Conditions	Marginal
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zob tracon : oak
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : instrument pilot : atp
Experience	flight time last 90 days : 130 flight time total : 8500 flight time type : 1200
ASRS Report	133683
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Deviation

Narrative:

Approaching descent from northwest, in ZOB airspace (frequency 126.75) controller said 'cross polar at 10,000 and 250 KTS'. We replied 'roger, polar at 10, and 250'. The controller then said 'air carrier a proceed direct polar, crossing restriction still applies'. While in descent through 10,500, the controller said 'air carrier a, verify level at 12,000'. We responded, 'no, we were cleared to 10,000'. Controller then issued 11,000 and flight continued uneventfully. At no time did we receive or read back any clearance to cross polar intersection at other than 10,000. Controller thought he had given us a clearance that he never transmitted, or at least never received an acknowledgement from us on.

Original NASA ASRS Text

Title: FLT CREW CTLR MISUNDERSTANDING ABOUT THE ALT CLEARED TO.

Narrative: APCHING DESCENT FROM NW, IN ZOB AIRSPACE (FREQ 126.75) CTLR SAID 'CROSS POLAR AT 10,000 AND 250 KTS'. WE REPLIED 'ROGER, POLAR AT 10, AND 250'. THE CTLR THEN SAID 'ACR A PROCEED DIRECT POLAR, XING RESTRICTION STILL APPLIES'. WHILE IN DSCNT THROUGH 10,500, THE CTLR SAID 'ACR A, VERIFY LEVEL AT 12,000'. WE RESPONDED, 'NO, WE WERE CLRED TO 10,000'. CTLR THEN ISSUED 11,000 AND FLT CONTINUED UNEVENTFULLY. AT NO TIME DID WE RECEIVE OR READ BACK ANY CLRNC TO CROSS POLAR INTXN AT OTHER THAN 10,000. CTLR THOUGHT HE HAD GIVEN US A CLRNC THAT HE NEVER TRANSMITTED, OR AT LEAST NEVER RECEIVED AN ACKNOWLEDGEMENT FROM US ON.

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.