Narrative:

We were at 5000' heading 110 degrees on autoplt. While the first officer was off ATC frequency, we recevied a heading change from approach control. I read back the heading and because the aircraft radar was on, moved the heading bug to the heading via digital readout in the EFIS display. In doing so, I set 010 degrees instead of the 100 degrees I thought I read back to approach control. The heading change did not appear to be inconsistent with an approach to runway 18 as it could have been a turn to an extended downwind due to other aircraft on approach. The first officer came back to ATC frequency. We heard approach control tell another aircraft Y about traffic and ask if he still had visibility contact because the approach controller did not know its intentions. Hearing this conversation and being in VFR conditions, I scanned for traffic and spotted a commuter aircraft Y to my left and behind us approximately 1/2 mi away. The aircraft appeared to be descending and below our altitude. As I began a slow climb to ensure sep, ATC questioned our heading and told us to maintain 5000' and turn right to 080 degrees. I watched the commuter Y pass behind and below us. We were vectored for landing. I called approach control by phone and talked to 2 supervisors. The second had listened to a playback of the voice tape and stated that I had read back '100' degrees heading and then turned further than expected. I set and thought 010 degrees was the correct heading and had no nagging doubt of the heading being incorrect. The supervisor stated that there was no operational error as the commuter Y had us visly. No sudden evasive action was taken by us and it did not appear any was taken by the commuter. In my opinion, the aircraft did not come within 500' of each other. I did not hear the commuter Y report a near miss and it was not mentioned on radio or in telephone conversation with ATC. I sighted the commuter before approach control called us to question our heading and I wonder why approach did not call us earlier since the excessive turn was monitored by ATC. I believe 5 factors were involved: only 1 pilot listening to ATC radio at the time, concern for proper altimeter settings for landing, my concern to set a heading bug when the bug moves off the display with large heading change (on EFIS equipped airplanes the navigation display must be put in a 90 degree arc mode, 45 degrees either side of present heading, when the aircraft radar is on and the change here was from 110 degrees to 010 degrees or 100 degrees left), more easily reversible heading (ie, 010 mistaken for 100 compared to the unlikely 018 mistaken for 180), and ATC not questioning our turn earlier.

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Original NASA ASRS Text

Title: TRACK DEVIATION AND AIRBORNE CONFLICT FOR BACR MLG NEAR DFW.

Narrative: WE WERE AT 5000' HDG 110 DEGS ON AUTOPLT. WHILE THE F/O WAS OFF ATC FREQ, WE RECEVIED A HDG CHANGE FROM APCH CTL. I READ BACK THE HDG AND BECAUSE THE ACFT RADAR WAS ON, MOVED THE HDG BUG TO THE HDG VIA DIGITAL READOUT IN THE EFIS DISPLAY. IN DOING SO, I SET 010 DEGS INSTEAD OF THE 100 DEGS I THOUGHT I READ BACK TO APCH CTL. THE HDG CHANGE DID NOT APPEAR TO BE INCONSISTENT WITH AN APCH TO RWY 18 AS IT COULD HAVE BEEN A TURN TO AN EXTENDED DOWNWIND DUE TO OTHER ACFT ON APCH. THE F/O CAME BACK TO ATC FREQ. WE HEARD APCH CTL TELL ANOTHER ACFT Y ABOUT TFC AND ASK IF HE STILL HAD VIS CONTACT BECAUSE THE APCH CTLR DID NOT KNOW ITS INTENTIONS. HEARING THIS CONVERSATION AND BEING IN VFR CONDITIONS, I SCANNED FOR TFC AND SPOTTED A COMMUTER ACFT Y TO MY L AND BEHIND US APPROX 1/2 MI AWAY. THE ACFT APPEARED TO BE DSNDING AND BELOW OUR ALT. AS I BEGAN A SLOW CLB TO ENSURE SEP, ATC QUESTIONED OUR HDG AND TOLD US TO MAINTAIN 5000' AND TURN R TO 080 DEGS. I WATCHED THE COMMUTER Y PASS BEHIND AND BELOW US. WE WERE VECTORED FOR LNDG. I CALLED APCH CTL BY PHONE AND TALKED TO 2 SUPVRS. THE SECOND HAD LISTENED TO A PLAYBACK OF THE VOICE TAPE AND STATED THAT I HAD READ BACK '100' DEGS HDG AND THEN TURNED FURTHER THAN EXPECTED. I SET AND THOUGHT 010 DEGS WAS THE CORRECT HDG AND HAD NO NAGGING DOUBT OF THE HDG BEING INCORRECT. THE SUPVR STATED THAT THERE WAS NO OPERROR AS THE COMMUTER Y HAD US VISLY. NO SUDDEN EVASIVE ACTION WAS TAKEN BY US AND IT DID NOT APPEAR ANY WAS TAKEN BY THE COMMUTER. IN MY OPINION, THE ACFT DID NOT COME WITHIN 500' OF EACH OTHER. I DID NOT HEAR THE COMMUTER Y RPT A NEAR MISS AND IT WAS NOT MENTIONED ON RADIO OR IN TELEPHONE CONVERSATION WITH ATC. I SIGHTED THE COMMUTER BEFORE APCH CTL CALLED US TO QUESTION OUR HDG AND I WONDER WHY APCH DID NOT CALL US EARLIER SINCE THE EXCESSIVE TURN WAS MONITORED BY ATC. I BELIEVE 5 FACTORS WERE INVOLVED: ONLY 1 PLT LISTENING TO ATC RADIO AT THE TIME, CONCERN FOR PROPER ALTIMETER SETTINGS FOR LNDG, MY CONCERN TO SET A HDG BUG WHEN THE BUG MOVES OFF THE DISPLAY WITH LARGE HDG CHANGE (ON EFIS EQUIPPED AIRPLANES THE NAV DISPLAY MUST BE PUT IN A 90 DEG ARC MODE, 45 DEGS EITHER SIDE OF PRESENT HDG, WHEN THE ACFT RADAR IS ON AND THE CHANGE HERE WAS FROM 110 DEGS TO 010 DEGS OR 100 DEGS L), MORE EASILY REVERSIBLE HDG (IE, 010 MISTAKEN FOR 100 COMPARED TO THE UNLIKELY 018 MISTAKEN FOR 180), AND ATC NOT QUESTIONING OUR TURN EARLIER.

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.