Confusion over actual cleared altitude. Potential conflict.

Attributes
ACN	113553
Time
Date	198906
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : oak
State Reference	CA
Altitude	msl bound lower : 9000 msl bound upper : 10000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : oak
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	climbout : intermediate altitude
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 : 250 flight time total : 15000 flight time type : 5000
ASRS Report	113553
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 270 flight time total : 8500 flight time type : 4000
ASRS Report	113886
Events
Anomaly	conflict : airborne less severe non adherence : required legal separation other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance none taken : detected after the fact other
Consequence	Other
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Deviation

Narrative:

Initial clearance via clearance delivery was to climb and maintain 10,000'. On initial contact with departure control we were again cleared to 10,000'. After leveling at 10,000 we were vectored with a 'tight' left turn for traffic followed by a right turn. Subsequently the controller said 'I thought I cleared you to 9000''. Perhaps he was overloaded due to numerous departures. Needs more help and more frequencys. Supplemental information from acn 113886: immediately after our initial contact with bay approach, the controller advised us of a 'NORDO' aircraft and issued us additional headings to avoid a conflict. It appeared the controller became overly concerned with this aircraft and may have not listened to our readback of 10,000' of which he assigned to us.

Original NASA ASRS Text

Title: CONFUSION OVER ACTUAL CLEARED ALT. POTENTIAL CONFLICT.

Narrative: INITIAL CLRNC VIA CLRNC DELIVERY WAS TO CLIMB AND MAINTAIN 10,000'. ON INITIAL CONTACT WITH DEP CTL WE WERE AGAIN CLRED TO 10,000'. AFTER LEVELING AT 10,000 WE WERE VECTORED WITH A 'TIGHT' LEFT TURN FOR TFC FOLLOWED BY A RIGHT TURN. SUBSEQUENTLY THE CTLR SAID 'I THOUGHT I CLRED YOU TO 9000''. PERHAPS HE WAS OVERLOADED DUE TO NUMEROUS DEPS. NEEDS MORE HELP AND MORE FREQS. SUPPLEMENTAL INFORMATION FROM ACN 113886: IMMEDIATELY AFTER OUR INITIAL CONTACT WITH BAY APCH, THE CTLR ADVISED US OF A 'NORDO' ACFT AND ISSUED US ADDITIONAL HDGS TO AVOID A CONFLICT. IT APPEARED THE CTLR BECAME OVERLY CONCERNED WITH THIS ACFT AND MAY HAVE NOT LISTENED TO OUR READBACK OF 10,000' OF WHICH HE ASSIGNED TO US.

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.