Air carrier flight crew has heading deviation due clearance confusion.

Attributes
ACN	160228
Time
Date	199010
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : sat
State Reference	TX
Altitude	msl bound lower : 23000 msl bound upper : 24000
Environment
Flight Conditions	Mixed
Light	Dawn
Aircraft 1
Controlling Facilities	artcc : zhu tower : clt
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 210 flight time total : 18000 flight time type : 10000
ASRS Report	160228
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	non adherence : clearance other anomaly other other spatial deviation
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	other
Situations
ATC Facility	procedure or policy : unspecified

Narrative:

We were from sat to den. Climbing out of sat we were talking with houston center on frequency 132.4 or 132.72. Center was very busy working more than one frequency at the same time. It was very difficult to get center to answer our transmission as he was working other aircraft that was not on our frequency. We were assigned heading 300 degree and cleared to FL230. We were given new clearance to fly heading 335 degree and climb to FL350 and direct abi when able. After turning to 335 degree center ask us our heading and we said 335 degree. He said he cleared us to turn to 335 degree after leaving FL240. We informed him we did not receive 'after leaving FL240.' he gave us left turn to 300 degree and maintain FL240. Which we did. He made us repeat the next clearance twice saying he didn't hear us repeat all of the clearance. It was very apparent other aircraft were transmitting and we were cutting each other out. Solution. One frequency per controller.

Original NASA ASRS Text

Title: ACR FLT CREW HAS HEADING DEVIATION DUE CLRNC CONFUSION.

Narrative: WE WERE FROM SAT TO DEN. CLBING OUT OF SAT WE WERE TALKING WITH HOUSTON CTR ON FREQ 132.4 OR 132.72. CTR WAS VERY BUSY WORKING MORE THAN ONE FREQ AT THE SAME TIME. IT WAS VERY DIFFICULT TO GET CTR TO ANSWER OUR XMISSION AS HE WAS WORKING OTHER ACFT THAT WAS NOT ON OUR FREQ. WE WERE ASSIGNED HDG 300 DEG AND CLRED TO FL230. WE WERE GIVEN NEW CLRNC TO FLY HDG 335 DEG AND CLB TO FL350 AND DIRECT ABI WHEN ABLE. AFTER TURNING TO 335 DEG CTR ASK US OUR HDG AND WE SAID 335 DEG. HE SAID HE CLRED US TO TURN TO 335 DEG AFTER LEAVING FL240. WE INFORMED HIM WE DID NOT RECEIVE 'AFTER LEAVING FL240.' HE GAVE US L TURN TO 300 DEG AND MAINTAIN FL240. WHICH WE DID. HE MADE US REPEAT THE NEXT CLRNC TWICE SAYING HE DIDN'T HEAR US REPEAT ALL OF THE CLRNC. IT WAS VERY APPARENT OTHER ACFT WERE XMITTING AND WE WERE CUTTING EACH OTHER OUT. SOLUTION. ONE FREQ PER CTLR.

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.