Narrative:

Scheduled part 121 flight departed bpt for dfw at XA52 local clearance to climb to 7000 ft. Tops of lower layer at about 3000 ft MSL. Level at 7000 ft, in contact with houston center, heading 320 degrees magnetic vector for lufkin. Center calls traffic at 2 O'clock, wbound, at 8000 ft MSL. I responded 'negative contact, searching' a few seconds later I made visual contact with traffic, asked the captain if he had the traffic, to which he responded in the affirmative, and informed center that traffic was in sight. At this time the traffic appeared about 3-4 mi away. Center asked if we wanted to climb VFR to 16000 ft if we could maintain visual separation with the traffic. I looked at captain and asked if he wanted that clearance and he responded in the affirmative. I dialed the preselect to 16000 ft and told center that we would accept a VFR climb to 16000 ft and they responded with the clearance and advised us to maintain visual separation and climb to 16000 ft. A few seconds later, our traffic, an ATR 42 wbound, called us in sight (center was in contact with the ATR and had advised the ATR of our aircraft also). The captain flying my aircraft initiated a climb. I again looked at him and asked if he had the ATR, which was now above us to the 2- 3 O'clock position, about 3 mi. He said 'yes' and I looked back to watch the traffic as it appeared it would pass above us. As we approached 7500 ft MSL on my altimeter, I said to the captain 'you may want to level off here until he passes.' the captain agreed and I felt him initiate a level off as I again turned my attention to the traffic, now about 1-2 mi away. As the traffic approached and was about to pass above us and to our left rear I noticed the ATR initiate what appeared to be a left turn. Several seconds later, when the traffic was clear to our left, the pilot of the ATR called center in an agitated voice and asked the center about our aircraft and why we were 'so close' or words to that effect. Center advised that we were maintaining visual separation in the climb. The ATR said that we 'were not doing a good job of it' and that their aircraft (the art) had to make an 'evasive maneuver' which some 'people were not happy about.' he later asked the same controller for our flight number and company name. We continued our climb and our flight concluded in dfw uneventfully. We asked the center controller if she had 'any problem or concern with our actions.' she replied 'no sir, I have no problem with anything you did.' when we landed in dallas the captain and I asked our flight attendant if she or any passenger saw any aircraft pass us during the flight or if she felt any unusual maneuvers. She replied no to both questions. I believe that despite the fact that we passed well below the ATR that he perhaps was surprised by our position and relative distance and had little time to accurately judge our separation. We had the advantage of tracking the ATR visually against a blue sky for several mi while perhaps he did not actually make good visual contact with us until shortly before we passed below him despite the maneuvers they were entirely unnecessary.

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Original NASA ASRS Text

Title: VISUAL SEPARATION -- 1 ACR CREW HAD A VISUAL CLB CLRNC. EACH FLC HAD THE OTHER IN SIGHT AND THE CLBING ACFT STOPPED 500 FT BELOW, BUT THE OTHER TOOK EVASIVE ACTION. PROBABLY AN OPTICAL ILLUSION.

Narrative: SCHEDULED PART 121 FLT DEPARTED BPT FOR DFW AT XA52 LCL CLRNC TO CLB TO 7000 FT. TOPS OF LOWER LAYER AT ABOUT 3000 FT MSL. LEVEL AT 7000 FT, IN CONTACT WITH HOUSTON CTR, HDG 320 DEGS MAGNETIC VECTOR FOR LUFKIN. CTR CALLS TFC AT 2 O'CLOCK, WBOUND, AT 8000 FT MSL. I RESPONDED 'NEGATIVE CONTACT, SEARCHING' A FEW SECONDS LATER I MADE VISUAL CONTACT WITH TFC, ASKED THE CAPT IF HE HAD THE TFC, TO WHICH HE RESPONDED IN THE AFFIRMATIVE, AND INFORMED CTR THAT TFC WAS IN SIGHT. AT THIS TIME THE TFC APPEARED ABOUT 3-4 MI AWAY. CTR ASKED IF WE WANTED TO CLB VFR TO 16000 FT IF WE COULD MAINTAIN VISUAL SEPARATION WITH THE TFC. I LOOKED AT CAPT AND ASKED IF HE WANTED THAT CLRNC AND HE RESPONDED IN THE AFFIRMATIVE. I DIALED THE PRESELECT TO 16000 FT AND TOLD CTR THAT WE WOULD ACCEPT A VFR CLB TO 16000 FT AND THEY RESPONDED WITH THE CLRNC AND ADVISED US TO MAINTAIN VISUAL SEPARATION AND CLB TO 16000 FT. A FEW SECONDS LATER, OUR TFC, AN ATR 42 WBOUND, CALLED US IN SIGHT (CTR WAS IN CONTACT WITH THE ATR AND HAD ADVISED THE ATR OF OUR ACFT ALSO). THE CAPT FLYING MY ACFT INITIATED A CLB. I AGAIN LOOKED AT HIM AND ASKED IF HE HAD THE ATR, WHICH WAS NOW ABOVE US TO THE 2- 3 O'CLOCK POS, ABOUT 3 MI. HE SAID 'YES' AND I LOOKED BACK TO WATCH THE TFC AS IT APPEARED IT WOULD PASS ABOVE US. AS WE APCHED 7500 FT MSL ON MY ALTIMETER, I SAID TO THE CAPT 'YOU MAY WANT TO LEVEL OFF HERE UNTIL HE PASSES.' THE CAPT AGREED AND I FELT HIM INITIATE A LEVEL OFF AS I AGAIN TURNED MY ATTN TO THE TFC, NOW ABOUT 1-2 MI AWAY. AS THE TFC APCHED AND WAS ABOUT TO PASS ABOVE US AND TO OUR L REAR I NOTICED THE ATR INITIATE WHAT APPEARED TO BE A L TURN. SEVERAL SECONDS LATER, WHEN THE TFC WAS CLR TO OUR L, THE PLT OF THE ATR CALLED CTR IN AN AGITATED VOICE AND ASKED THE CTR ABOUT OUR ACFT AND WHY WE WERE 'SO CLOSE' OR WORDS TO THAT EFFECT. CTR ADVISED THAT WE WERE MAINTAINING VISUAL SEPARATION IN THE CLB. THE ATR SAID THAT WE 'WERE NOT DOING A GOOD JOB OF IT' AND THAT THEIR ACFT (THE ART) HAD TO MAKE AN 'EVASIVE MANEUVER' WHICH SOME 'PEOPLE WERE NOT HAPPY ABOUT.' HE LATER ASKED THE SAME CTLR FOR OUR FLT NUMBER AND COMPANY NAME. WE CONTINUED OUR CLB AND OUR FLT CONCLUDED IN DFW UNEVENTFULLY. WE ASKED THE CTR CTLR IF SHE HAD 'ANY PROB OR CONCERN WITH OUR ACTIONS.' SHE REPLIED 'NO SIR, I HAVE NO PROB WITH ANYTHING YOU DID.' WHEN WE LANDED IN DALLAS THE CAPT AND I ASKED OUR FLT ATTENDANT IF SHE OR ANY PAX SAW ANY ACFT PASS US DURING THE FLT OR IF SHE FELT ANY UNUSUAL MANEUVERS. SHE REPLIED NO TO BOTH QUESTIONS. I BELIEVE THAT DESPITE THE FACT THAT WE PASSED WELL BELOW THE ATR THAT HE PERHAPS WAS SURPRISED BY OUR POS AND RELATIVE DISTANCE AND HAD LITTLE TIME TO ACCURATELY JUDGE OUR SEPARATION. WE HAD THE ADVANTAGE OF TRACKING THE ATR VISUALLY AGAINST A BLUE SKY FOR SEVERAL MI WHILE PERHAPS HE DID NOT ACTUALLY MAKE GOOD VISUAL CONTACT WITH US UNTIL SHORTLY BEFORE WE PASSED BELOW HIM DESPITE THE MANEUVERS THEY WERE ENTIRELY UNNECESSARY.

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.