Narrative:

Our aircraft was just cleared to turn 30 degree left (where discrepancy was) and to climb to FL310. I was in the right seat, acknowledged the clearance, and was in the process of setting the new altitude in the alerter, turning my heading bug, and tuning up the dnv VOR, where we were to be cleared to next. All of which took approximately 30-40 seconds. Upon finishing I noticed that we were 30 degrees right of previous heading. I was opening my mouth to question the PF of the discrepancy when the TCASII had a visual TA (color of target changed), at the same time the controller asked if we had started our turn and immediately issued a turn to 080 degrees. We rolled into a 45 degree bank left turn, as I decreased the scale on the TCASII at 5 NM. He was right on the edge of the circle and at 2 O'clock position. Somewhere in our turn, the other aircraft was given a turn to its left. (At that time the estimated 5 NM and -200 ft was observed.) after a few more seconds, both aircraft were cleared back on course. The commercial aircraft (I believe to be an air carrier Y) questioned if we had exceeded 5 NM of clearance and the controller said it did not appear to have been exceeded, but with the turning, wasn't exactly sure. He also said nothing 'came down from the wash-out desk' so it appeared to be ok. The problem was discovered by all 3 parties at approximately the same time. The aircraft had TCASII alerts, and the controller being alert, noticed. The pilot flying at the time said he was sure he had heard right. He did not repeat the clearance to me after I accepted it, which may have caught the discrepancy. I let myself get busy and didn't follow through with making sure the clearance was carried out, which would have also caught the discrepancy. In short, the problem could have been resolved earlier, or at least noticed, and the clearance questioned at an earlier time. I would also note that I know that our crew had been up since XA00 and flown to fcm, waited all day, and departed there (fcm) at XL00 to return to our home. After waiting in the FBO there all day both the PF and I were acknowledging that we were tired and felt slow. I could also say that it is normal for the PF to repeat the clearance and for the PNF to check for discrepancy. I know I usually (almost always -- unless blatantly obvious) check the PF's actions. So, I may safely say fatigue was at least in some respect a factor. I feel more fatigue or 'brain dead' after sitting around all day after getting up early than if I am busy flying all day. The brain and physical inactivity catch up with me, as well as anyone. That's my perspectives and insights on the situation. Fatigue will sound an alarm in my subconscious even more now.

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Original NASA ASRS Text

Title: MISINTERPING THE DIRECTION OF A GIVEN 30 DEG TURN LEADS TO A WRONG DIRECTION OF TURN AND A TFC CONFLICT.

Narrative: OUR ACFT WAS JUST CLRED TO TURN 30 DEG L (WHERE DISCREPANCY WAS) AND TO CLB TO FL310. I WAS IN THE R SEAT, ACKNOWLEDGED THE CLRNC, AND WAS IN THE PROCESS OF SETTING THE NEW ALT IN THE ALERTER, TURNING MY HDG BUG, AND TUNING UP THE DNV VOR, WHERE WE WERE TO BE CLRED TO NEXT. ALL OF WHICH TOOK APPROX 30-40 SECONDS. UPON FINISHING I NOTICED THAT WE WERE 30 DEGS R OF PREVIOUS HDG. I WAS OPENING MY MOUTH TO QUESTION THE PF OF THE DISCREPANCY WHEN THE TCASII HAD A VISUAL TA (COLOR OF TARGET CHANGED), AT THE SAME TIME THE CTLR ASKED IF WE HAD STARTED OUR TURN AND IMMEDIATELY ISSUED A TURN TO 080 DEGS. WE ROLLED INTO A 45 DEG BANK L TURN, AS I DECREASED THE SCALE ON THE TCASII AT 5 NM. HE WAS RIGHT ON THE EDGE OF THE CIRCLE AND AT 2 O'CLOCK POS. SOMEWHERE IN OUR TURN, THE OTHER ACFT WAS GIVEN A TURN TO ITS L. (AT THAT TIME THE ESTIMATED 5 NM AND -200 FT WAS OBSERVED.) AFTER A FEW MORE SECONDS, BOTH ACFT WERE CLRED BACK ON COURSE. THE COMMERCIAL ACFT (I BELIEVE TO BE AN ACR Y) QUESTIONED IF WE HAD EXCEEDED 5 NM OF CLRNC AND THE CTLR SAID IT DID NOT APPEAR TO HAVE BEEN EXCEEDED, BUT WITH THE TURNING, WASN'T EXACTLY SURE. HE ALSO SAID NOTHING 'CAME DOWN FROM THE WASH-OUT DESK' SO IT APPEARED TO BE OK. THE PROB WAS DISCOVERED BY ALL 3 PARTIES AT APPROX THE SAME TIME. THE ACFT HAD TCASII ALERTS, AND THE CTLR BEING ALERT, NOTICED. THE PLT FLYING AT THE TIME SAID HE WAS SURE HE HAD HEARD RIGHT. HE DID NOT REPEAT THE CLRNC TO ME AFTER I ACCEPTED IT, WHICH MAY HAVE CAUGHT THE DISCREPANCY. I LET MYSELF GET BUSY AND DIDN'T FOLLOW THROUGH WITH MAKING SURE THE CLRNC WAS CARRIED OUT, WHICH WOULD HAVE ALSO CAUGHT THE DISCREPANCY. IN SHORT, THE PROB COULD HAVE BEEN RESOLVED EARLIER, OR AT LEAST NOTICED, AND THE CLRNC QUESTIONED AT AN EARLIER TIME. I WOULD ALSO NOTE THAT I KNOW THAT OUR CREW HAD BEEN UP SINCE XA00 AND FLOWN TO FCM, WAITED ALL DAY, AND DEPARTED THERE (FCM) AT XL00 TO RETURN TO OUR HOME. AFTER WAITING IN THE FBO THERE ALL DAY BOTH THE PF AND I WERE ACKNOWLEDGING THAT WE WERE TIRED AND FELT SLOW. I COULD ALSO SAY THAT IT IS NORMAL FOR THE PF TO REPEAT THE CLRNC AND FOR THE PNF TO CHK FOR DISCREPANCY. I KNOW I USUALLY (ALMOST ALWAYS -- UNLESS BLATANTLY OBVIOUS) CHK THE PF'S ACTIONS. SO, I MAY SAFELY SAY FATIGUE WAS AT LEAST IN SOME RESPECT A FACTOR. I FEEL MORE FATIGUE OR 'BRAIN DEAD' AFTER SITTING AROUND ALL DAY AFTER GETTING UP EARLY THAN IF I AM BUSY FLYING ALL DAY. THE BRAIN AND PHYSICAL INACTIVITY CATCH UP WITH ME, AS WELL AS ANYONE. THAT'S MY PERSPECTIVES AND INSIGHTS ON THE SIT. FATIGUE WILL SOUND AN ALARM IN MY SUBCONSCIOUS EVEN MORE NOW.

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.