Abbreviated a/north led to deviation from clearance.

Attributes
ACN	110421
Time
Date	198905
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : jot
State Reference	IL
Altitude	msl bound lower : 4000 msl bound upper : 5300
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zau tracon : ord
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Retractable Gear
Flight Phase	climbout : intermediate altitude cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private pilot : instrument
Experience	flight time last 90 days : 26 flight time total : 1855 flight time type : 710
ASRS Report	110421
Person 2
Affiliation	government : faa
Function	controller : departure
Qualification	controller : radar
Events
Anomaly	non adherence : clearance other anomaly other
Independent Detector	other controllera other flight crewa other other : unspecified
Resolutory Action	controller : issued new clearance none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	other

Narrative:

I was flying n-abcd south under IFR control with radar vectors to jot after leaving dpa. I contacted ord departure using the full call sign leaving 1800 for 3000' on a 180 degree heading. The controller accepted me with 'radar contact clearance delivery sierra.' before reaching 3000' he cleared me to 4000'. After a few mins the controller said, 'clearance delivery sierra, turn left to 140 degrees and climb to 6000'.' I acknowledged by 'clearance delivery sierra turn left to 140 degrees and climb to 6000'.' I was using the autoplt and climbed a 500 FPM turn to 140 degrees. When I was at 5300' the controller admonished me for leaving 4000' by stating, 'abcd sierra was not to leave an assigned altitude west/O permission.' I stated that I had received the direction from him. He stated that I was to return to 4000' immediately and that the previous instruction had been for D lima sierra. My passenger and I were each wearing headsets and my passenger stated that he had heard the controller issue to instruction to clearance delivery sierra, us. I quickly dropped altitude but at 4500' I was told to contact chicago center. I switched the frequency and called them using the full call sign and they acknowledged by stating, 'abcd sierra climb to 5000' and direct to pnt.' in a few mins again using the full call sign they moved me to 6000' and the remainder of the flight to spi was uneventful. Fortunately there was no accident but every controller in every communication to spi used the full call sign. I flew the return trip with flight following and again every controller used the full call sign in every call.

Original NASA ASRS Text

Title: ABBREVIATED A/N LED TO DEVIATION FROM CLRNC.

Narrative: I WAS FLYING N-ABCD S UNDER IFR CTL WITH RADAR VECTORS TO JOT AFTER LEAVING DPA. I CONTACTED ORD DEP USING THE FULL CALL SIGN LEAVING 1800 FOR 3000' ON A 180 DEG HDG. THE CTLR ACCEPTED ME WITH 'RADAR CONTACT CD SIERRA.' BEFORE REACHING 3000' HE CLRED ME TO 4000'. AFTER A FEW MINS THE CTLR SAID, 'CD SIERRA, TURN LEFT TO 140 DEGS AND CLB TO 6000'.' I ACKNOWLEDGED BY 'CD SIERRA TURN LEFT TO 140 DEGS AND CLB TO 6000'.' I WAS USING THE AUTOPLT AND CLBED A 500 FPM TURN TO 140 DEGS. WHEN I WAS AT 5300' THE CTLR ADMONISHED ME FOR LEAVING 4000' BY STATING, 'ABCD SIERRA WAS NOT TO LEAVE AN ASSIGNED ALT W/O PERMISSION.' I STATED THAT I HAD RECEIVED THE DIRECTION FROM HIM. HE STATED THAT I WAS TO RETURN TO 4000' IMMEDIATELY AND THAT THE PREVIOUS INSTRUCTION HAD BEEN FOR D LIMA SIERRA. MY PAX AND I WERE EACH WEARING HEADSETS AND MY PAX STATED THAT HE HAD HEARD THE CTLR ISSUE TO INSTRUCTION TO CD SIERRA, US. I QUICKLY DROPPED ALT BUT AT 4500' I WAS TOLD TO CONTACT CHICAGO CENTER. I SWITCHED THE FREQ AND CALLED THEM USING THE FULL CALL SIGN AND THEY ACKNOWLEDGED BY STATING, 'ABCD SIERRA CLB TO 5000' AND DIRECT TO PNT.' IN A FEW MINS AGAIN USING THE FULL CALL SIGN THEY MOVED ME TO 6000' AND THE REMAINDER OF THE FLT TO SPI WAS UNEVENTFUL. FORTUNATELY THERE WAS NO ACCIDENT BUT EVERY CTLR IN EVERY COM TO SPI USED THE FULL CALL SIGN. I FLEW THE RETURN TRIP WITH FLT FOLLOWING AND AGAIN EVERY CTLR USED THE FULL CALL SIGN IN EVERY CALL.

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.