A widebody transport misunderstood their heading clearance for an altitude clearance.

Attributes
ACN	225293
Time
Date	199211
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : jfk
State Reference	NY
Altitude	msl bound lower : 17000 msl bound upper : 17800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : n90
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	climbout : intermediate altitude cruise other
Route In Use	departure other enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 100 flight time total : 20000 flight time type : 75
ASRS Report	225293
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : flight engineer pilot : cfi pilot : atp
Experience	flight time last 90 days : 150 flight time total : 7500 flight time type : 150
ASRS Report	225029
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other other spatial deviation
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	other

Narrative:

Climb out of jfk, we leveled at 17000 ft, heading 040 degree. I expected clearance higher, and controllers transmission was garbled, but I heard 'climb to FL350.' I read back 'cleared to climb to FL350.' controller 'rogered.' as we passed through 17800, the controller said 'what's your altitude,' and I said '1700 ft FL350.' controller said it was a clearance to heading 350. I told her that I had read back 'climb to FL350.' another controller came on (supervisor) and cleared us to maintain 18000. I got the feeling that initial controller might have been a trainee, with supervisor looking over her shoulder. We had no traffic conflict. Solution: be more sure of clearance. I was expecting higher, and that's what I heard. Copilot said he also heard, 'climb to FL350.' we should have questioned this, as the heading was really more appropriate, than an altitude clearance. The controller was the second segment departure (approach) controller, and they normally would not give clearance to FL350, but some lower altitude.

Original NASA ASRS Text

Title: A WDB MISUNDERSTOOD THEIR HDG CLRNC FOR AN ALT CLRNC.

Narrative: CLB OUT OF JFK, WE LEVELED AT 17000 FT, HDG 040 DEG. I EXPECTED CLRNC HIGHER, AND CTLRS XMISSION WAS GARBLED, BUT I HEARD 'CLB TO FL350.' I READ BACK 'CLRED TO CLB TO FL350.' CTLR 'ROGERED.' AS WE PASSED THROUGH 17800, THE CTLR SAID 'WHAT'S YOUR ALT,' AND I SAID '1700 FT FL350.' CTLR SAID IT WAS A CLRNC TO HDG 350. I TOLD HER THAT I HAD READ BACK 'CLB TO FL350.' ANOTHER CTLR CAME ON (SUPVR) AND CLRED US TO MAINTAIN 18000. I GOT THE FEELING THAT INITIAL CTLR MIGHT HAVE BEEN A TRAINEE, WITH SUPVR LOOKING OVER HER SHOULDER. WE HAD NO TFC CONFLICT. SOLUTION: BE MORE SURE OF CLRNC. I WAS EXPECTING HIGHER, AND THAT'S WHAT I HEARD. COPLT SAID HE ALSO HEARD, 'CLB TO FL350.' WE SHOULD HAVE QUESTIONED THIS, AS THE HDG WAS REALLY MORE APPROPRIATE, THAN AN ALT CLRNC. THE CTLR WAS THE SECOND SEGMENT DEP (APCH) CTLR, AND THEY NORMALLY WOULD NOT GIVE CLRNC TO FL350, BUT SOME LOWER ALT.

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.