Air carrier large transport non adherence to ATC clearance. Clearance amended heading assignment.

Attributes
ACN	106300
Time
Date	198903
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : obk airport : ord
State Reference	IL
Altitude	msl bound lower : 13000 msl bound upper : 13000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ord artcc : zkc
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	climbout : intermediate altitude cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 170 flight time total : 5500 flight time type : 1200
ASRS Report	106300
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi pilot : flight engineer pilot : commercial pilot : instrument
Experience	flight time last 90 days : 200 flight time total : 14000 flight time type : 2000
ASRS Report	106130
Events
Anomaly	non adherence : clearance other spatial deviation
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation other

Narrative:

Chicago departure issued our flight a turn to 060 degrees and climb to 13000'. Then they issued a 090 degree heading, call sign unknown (unintelligible) which was acknowledged by another flight by that flight simply saying, 'thank you.' 2 mins later chicago departure told us he had issued a 090 degree heading to us, and that we acknowledged the call with a 'thank you,' which we never did. We turned to the heading 090 degrees and we were handed off to center. The aircraft that actually said 'thank you' had gone to another frequency, not been able to check in, came back to 125.0 and requested the previously assigned frequency. The controller then issued a heading and frequency with unknown call sign which the other aircraft acknowledged. One factor attributed to 2 separate individuals contributed to this miscom: the other flight not using a call sign to acknowledge a call, and ATC not verifying his clearance was accepted by the proper individual by assuming the proper individual had accepted the clearance with a simple acknowledgement of 'thank you.' full call signs used by both parties would have prevented this.

Original NASA ASRS Text

Title: ACR LGT NON ADHERENCE TO ATC CLRNC. CLRNC AMENDED HEADING ASSIGNMENT.

Narrative: CHICAGO DEP ISSUED OUR FLT A TURN TO 060 DEGS AND CLB TO 13000'. THEN THEY ISSUED A 090 DEG HDG, CALL SIGN UNKNOWN (UNINTELLIGIBLE) WHICH WAS ACKNOWLEDGED BY ANOTHER FLT BY THAT FLT SIMPLY SAYING, 'THANK YOU.' 2 MINS LATER CHICAGO DEP TOLD US HE HAD ISSUED A 090 DEG HDG TO US, AND THAT WE ACKNOWLEDGED THE CALL WITH A 'THANK YOU,' WHICH WE NEVER DID. WE TURNED TO THE HDG 090 DEGS AND WE WERE HANDED OFF TO CENTER. THE ACFT THAT ACTUALLY SAID 'THANK YOU' HAD GONE TO ANOTHER FREQ, NOT BEEN ABLE TO CHK IN, CAME BACK TO 125.0 AND REQUESTED THE PREVIOUSLY ASSIGNED FREQ. THE CTLR THEN ISSUED A HDG AND FREQ WITH UNKNOWN CALL SIGN WHICH THE OTHER ACFT ACKNOWLEDGED. ONE FACTOR ATTRIBUTED TO 2 SEPARATE INDIVIDUALS CONTRIBUTED TO THIS MISCOM: THE OTHER FLT NOT USING A CALL SIGN TO ACKNOWLEDGE A CALL, AND ATC NOT VERIFYING HIS CLRNC WAS ACCEPTED BY THE PROPER INDIVIDUAL BY ASSUMING THE PROPER INDIVIDUAL HAD ACCEPTED THE CLRNC WITH A SIMPLE ACKNOWLEDGEMENT OF 'THANK YOU.' FULL CALL SIGNS USED BY BOTH PARTIES WOULD HAVE PREVENTED THIS.

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.