Narrative:

I was captain and PF on an medium large transport flight from cvg to bwi. We were climbing above 10,000' on a radar vector approximately 080 degree at a speed of 300 KIAS. Flight conditions were good with some low cumulus and scattered high cirrus. We were just exiting the haze layer and visibility was about 10 mi. ZID cleared us to proceed direct to hvq and I dialed in the #1 VOR from memory while the first officer consulted his chart. I initiated a slow autoplt turn towards the VOR (approximately 095 degree) and pulled out my map to double-check my navigation. An agitated call from center followed, 'XXX999, VFR traffic 12 O'clock less than a mi, mode C readout is 13,500'!' we both focused our attention directly ahead but at first saw nothing. Then, there he was, a single-engine, type flying southbound, and we appeared to be heading right for him! I immediately disconnected the autoplt and leveled off, banking slightly to the left. We had sufficient time that a violent maneuver was not required but the miss distance was less than comfortable -- a few hundred feet below and behind. I glanced down and noted our altimeter read 13,500'. The other aircraft did not appear to see us and took no evasive action. The time from first sighting to closest passage was less than 10 seconds. The controller made a statement to the effect that the traffic had just appeared on his scope. After the copilot and I expressed a few 'wows' and 'holy mackerels' to each other the ATC supervisor contacted us by radio and informed us they would be initiating a near miss investigation. I said 'fine' and reported the incident to my chief pilot by phone and, subsequently, in a written crew irregular operation report. This incident crystalized for me an opinion I have held for some time -- that even though an object is visible, the human eye may not see it. There is a 'zone of recognition' which is invariably less than the prevailing visibility. Large aircraft may be sighted up to 15-20 mi while light planes may not be picked up until 2-3 mi under the same conditions. Lighting and background also play a part of decreasing visual acuity. A backlit aircraft (appearing dark) against an undercast is easy to pick up, whereas, a frontlit plane (especially a white-painted one) is very difficult to pick out against a bright background. The human eye is much more sensitive to moving rather than stationary objects. Unfortunately, aircraft posing a collision hazard will not have any relative motion, only decreasing range. This incident was a perfect example of the breakdown of the outdated concept of see-and-be-seen. We were faced with a small, white aircraft, brightly frontlit, blending into a background of scattered cirrus, and no relative motion. We were approaching the other plane from his 2-3 O'clock low, making it less likely he would see us from his left seat position. Factor in the distractions of navigation and the time available for visual acquisition becomes exceedingly short. Assuming our closure speed was in the neighborhood of 360 KTS, visual sighting at 3 mi (the normal maximum for most small traffic) would translate into 30 seconds time to react. In this instance, even though we were alerted exactly where to look, we did not distinguish the target until it was a mi or less away. Time available for us to avoid the collision was less than 10 seconds! How many times have we had our attention diverted inside the cockpit for much longer than that? The other pilot was operating under VFR flight rules and never saw us at all. Clearly, the see-and-be-seen concept for collision avoidance has its limitations. Furthermore, pilots on an IFR flight plan are held accountable for navigation within very precise limits. Compliance with these requirements cannot help but degrade visual lookout no matter how conscientiously they may try to operate the aircraft. VFR aircraft are just as deadly a hazard as those on IFR flight plans. ATC must be given the means and assume the responsibility of providing advisory information on all known traffic, both VFR and IFR, at all times, not just when time permits or, as in our case, when the conflict alert goes off. As part of this tasking all VFR traffic would have to squawk mode C or be restr to operation below and outside of air carrier operations, such as below 3000' AGL and outside terminal area control zones. No doubts, such a proposal would arouse intense opposition in some quarters. We then have to put a price on continuing with liberal but outmoded flight rules. Is it worth another cerritos? I know how my vote would be cast. Supplemental information from acn 125081: it would have been beneficial for all parties involved if he had been also talking to center (flight following).

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Original NASA ASRS Text

Title: NMAC.

Narrative: I WAS CAPT AND PF ON AN MLG FLT FROM CVG TO BWI. WE WERE CLIMBING ABOVE 10,000' ON A RADAR VECTOR APPROX 080 DEG AT A SPEED OF 300 KIAS. FLT CONDITIONS WERE GOOD WITH SOME LOW CUMULUS AND SCATTERED HIGH CIRRUS. WE WERE JUST EXITING THE HAZE LAYER AND VISIBILITY WAS ABOUT 10 MI. ZID CLRED US TO PROCEED DIRECT TO HVQ AND I DIALED IN THE #1 VOR FROM MEMORY WHILE THE F/O CONSULTED HIS CHART. I INITIATED A SLOW AUTOPLT TURN TOWARDS THE VOR (APPROX 095 DEG) AND PULLED OUT MY MAP TO DOUBLE-CHECK MY NAVIGATION. AN AGITATED CALL FROM CENTER FOLLOWED, 'XXX999, VFR TFC 12 O'CLOCK LESS THAN A MI, MODE C READOUT IS 13,500'!' WE BOTH FOCUSED OUR ATTN DIRECTLY AHEAD BUT AT FIRST SAW NOTHING. THEN, THERE HE WAS, A SINGLE-ENGINE, TYPE FLYING SBND, AND WE APPEARED TO BE HDG RIGHT FOR HIM! I IMMEDIATELY DISCONNECTED THE AUTOPLT AND LEVELED OFF, BANKING SLIGHTLY TO THE LEFT. WE HAD SUFFICIENT TIME THAT A VIOLENT MANEUVER WAS NOT REQUIRED BUT THE MISS DISTANCE WAS LESS THAN COMFORTABLE -- A FEW HUNDRED FEET BELOW AND BEHIND. I GLANCED DOWN AND NOTED OUR ALTIMETER READ 13,500'. THE OTHER ACFT DID NOT APPEAR TO SEE US AND TOOK NO EVASIVE ACTION. THE TIME FROM FIRST SIGHTING TO CLOSEST PASSAGE WAS LESS THAN 10 SECONDS. THE CTLR MADE A STATEMENT TO THE EFFECT THAT THE TFC HAD JUST APPEARED ON HIS SCOPE. AFTER THE COPLT AND I EXPRESSED A FEW 'WOWS' AND 'HOLY MACKERELS' TO EACH OTHER THE ATC SUPVR CONTACTED US BY RADIO AND INFORMED US THEY WOULD BE INITIATING A NEAR MISS INVESTIGATION. I SAID 'FINE' AND REPORTED THE INCIDENT TO MY CHIEF PLT BY PHONE AND, SUBSEQUENTLY, IN A WRITTEN CREW IRREGULAR OPERATION REPORT. THIS INCIDENT CRYSTALIZED FOR ME AN OPINION I HAVE HELD FOR SOME TIME -- THAT EVEN THOUGH AN OBJECT IS VISIBLE, THE HUMAN EYE MAY NOT SEE IT. THERE IS A 'ZONE OF RECOGNITION' WHICH IS INVARIABLY LESS THAN THE PREVAILING VISIBILITY. LARGE ACFT MAY BE SIGHTED UP TO 15-20 MI WHILE LIGHT PLANES MAY NOT BE PICKED UP UNTIL 2-3 MI UNDER THE SAME CONDITIONS. LIGHTING AND BACKGROUND ALSO PLAY A PART OF DECREASING VISUAL ACUITY. A BACKLIT ACFT (APPEARING DARK) AGAINST AN UNDERCAST IS EASY TO PICK UP, WHEREAS, A FRONTLIT PLANE (ESPECIALLY A WHITE-PAINTED ONE) IS VERY DIFFICULT TO PICK OUT AGAINST A BRIGHT BACKGROUND. THE HUMAN EYE IS MUCH MORE SENSITIVE TO MOVING RATHER THAN STATIONARY OBJECTS. UNFORTUNATELY, ACFT POSING A COLLISION HAZARD WILL NOT HAVE ANY RELATIVE MOTION, ONLY DECREASING RANGE. THIS INCIDENT WAS A PERFECT EXAMPLE OF THE BREAKDOWN OF THE OUTDATED CONCEPT OF SEE-AND-BE-SEEN. WE WERE FACED WITH A SMALL, WHITE ACFT, BRIGHTLY FRONTLIT, BLENDING INTO A BACKGROUND OF SCATTERED CIRRUS, AND NO RELATIVE MOTION. WE WERE APCHING THE OTHER PLANE FROM HIS 2-3 O'CLOCK LOW, MAKING IT LESS LIKELY HE WOULD SEE US FROM HIS LEFT SEAT POSITION. FACTOR IN THE DISTRACTIONS OF NAVIGATION AND THE TIME AVAILABLE FOR VISUAL ACQUISITION BECOMES EXCEEDINGLY SHORT. ASSUMING OUR CLOSURE SPEED WAS IN THE NEIGHBORHOOD OF 360 KTS, VISUAL SIGHTING AT 3 MI (THE NORMAL MAX FOR MOST SMALL TFC) WOULD TRANSLATE INTO 30 SECONDS TIME TO REACT. IN THIS INSTANCE, EVEN THOUGH WE WERE ALERTED EXACTLY WHERE TO LOOK, WE DID NOT DISTINGUISH THE TARGET UNTIL IT WAS A MI OR LESS AWAY. TIME AVAILABLE FOR US TO AVOID THE COLLISION WAS LESS THAN 10 SECONDS! HOW MANY TIMES HAVE WE HAD OUR ATTN DIVERTED INSIDE THE COCKPIT FOR MUCH LONGER THAN THAT? THE OTHER PLT WAS OPERATING UNDER VFR FLT RULES AND NEVER SAW US AT ALL. CLEARLY, THE SEE-AND-BE-SEEN CONCEPT FOR COLLISION AVOIDANCE HAS ITS LIMITATIONS. FURTHERMORE, PLTS ON AN IFR FLT PLAN ARE HELD ACCOUNTABLE FOR NAVIGATION WITHIN VERY PRECISE LIMITS. COMPLIANCE WITH THESE REQUIREMENTS CANNOT HELP BUT DEGRADE VISUAL LOOKOUT NO MATTER HOW CONSCIENTIOUSLY THEY MAY TRY TO OPERATE THE ACFT. VFR ACFT ARE JUST AS DEADLY A HAZARD AS THOSE ON IFR FLT PLANS. ATC MUST BE GIVEN THE MEANS AND ASSUME THE RESPONSIBILITY OF PROVIDING ADVISORY INFO ON ALL KNOWN TFC, BOTH VFR AND IFR, AT ALL TIMES, NOT JUST WHEN TIME PERMITS OR, AS IN OUR CASE, WHEN THE CONFLICT ALERT GOES OFF. AS PART OF THIS TASKING ALL VFR TFC WOULD HAVE TO SQUAWK MODE C OR BE RESTR TO OPERATION BELOW AND OUTSIDE OF AIR CARRIER OPERATIONS, SUCH AS BELOW 3000' AGL AND OUTSIDE TERMINAL AREA CTL ZONES. NO DOUBTS, SUCH A PROPOSAL WOULD AROUSE INTENSE OPPOSITION IN SOME QUARTERS. WE THEN HAVE TO PUT A PRICE ON CONTINUING WITH LIBERAL BUT OUTMODED FLT RULES. IS IT WORTH ANOTHER CERRITOS? I KNOW HOW MY VOTE WOULD BE CAST. SUPPLEMENTAL INFORMATION FROM ACN 125081: IT WOULD HAVE BEEN BENEFICIAL FOR ALL PARTIES INVOLVED IF HE HAD BEEN ALSO TALKING TO CENTER (FLT FOLLOWING).

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.