Medium large transport flight crew misinterprets clearance. Heading deviation.

Attributes
ACN	136683
Time
Date	199002
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : otk
State Reference	GA
Altitude	msl bound lower : 27000 msl bound upper : 27000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zjx
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	cruise other descent other
Route In Use	arrival star : star
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 160 flight time total : 7500 flight time type : 2500
ASRS Report	136683
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 230 flight time total : 15200 flight time type : 195
ASRS Report	136684
Events
Anomaly	non adherence : published procedure non adherence : clearance other anomaly other other spatial deviation
Independent Detector	other controllera other flight crewa
Resolutory Action	controller : issued new clearance flight crew : became reoriented
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were coming down J-89 to otk and the leese 6 arrival to orlando. Just north of otk I went off the frequency. We were cleared to cross 15 south of otk at FL270. When I came back I asked the captain what the clearance was. He told me. I looked at his CDI and where we were. He had the 170 degree course dialed in. I looked at my approach plate and then asked, aren't we supposed to be on the 126 degree radial out of otk. He agreed and we were in the turn to intercept it when ATC called us and asked us where we were going. He said we were 30 south of otk and tracking away from the arrival. What may have caused the confusion was the clearance to cross '15 south'. More appropriate it should have been 15 southeast of otk. When the captain heard 15 south he saw the 170 degree radial out of amg and put that into his CDI. Imprecise clrncs lead to confusion. Also 2 pilot crews are an added workload. Also both of us were very tired from the trip schedule. I know we don't address crew fatigue but I believe this is the single most important cause of errors.

Original NASA ASRS Text

Title: MLG FLT CREW MISINTERPRETS CLRNC. HEADING DEVIATION.

Narrative: WE WERE COMING DOWN J-89 TO OTK AND THE LEESE 6 ARR TO ORLANDO. JUST N OF OTK I WENT OFF THE FREQ. WE WERE CLRED TO CROSS 15 S OF OTK AT FL270. WHEN I CAME BACK I ASKED THE CAPT WHAT THE CLRNC WAS. HE TOLD ME. I LOOKED AT HIS CDI AND WHERE WE WERE. HE HAD THE 170 DEG COURSE DIALED IN. I LOOKED AT MY APCH PLATE AND THEN ASKED, AREN'T WE SUPPOSED TO BE ON THE 126 DEG RADIAL OUT OF OTK. HE AGREED AND WE WERE IN THE TURN TO INTERCEPT IT WHEN ATC CALLED US AND ASKED US WHERE WE WERE GOING. HE SAID WE WERE 30 S OF OTK AND TRACKING AWAY FROM THE ARR. WHAT MAY HAVE CAUSED THE CONFUSION WAS THE CLRNC TO CROSS '15 SOUTH'. MORE APPROPRIATE IT SHOULD HAVE BEEN 15 SE OF OTK. WHEN THE CAPT HEARD 15 SOUTH HE SAW THE 170 DEG RADIAL OUT OF AMG AND PUT THAT INTO HIS CDI. IMPRECISE CLRNCS LEAD TO CONFUSION. ALSO 2 PLT CREWS ARE AN ADDED WORKLOAD. ALSO BOTH OF US WERE VERY TIRED FROM THE TRIP SCHEDULE. I KNOW WE DON'T ADDRESS CREW FATIGUE BUT I BELIEVE THIS IS THE SINGLE MOST IMPORTANT CAUSE OF ERRORS.

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.