Narrative:

Air carrier X roa to ric. While on a vector to a visual straight in to runway 02 a near miss occurred with air carrier Y, light transport. The reason no collision occurred was a direct result of TCASII. Richmond approach control had assigned us a heading of 150 degree at 5000 MSL and 210 KIAS. We had our TCASII on 10 NM scope and below RA/TA. I was flying the aircraft (first officer) on autoplt. I noticed a conflict with a target on the scope which was about 15-20 degrees right of center and showing 800-900 ft above us in a descent. As I mentioned it to the captain we watched it for no more than a few seconds in order to get some sort of idea on its track, we saw that it was definitely going to be a conflict so I took the aircraft off of autoplt. From this point things happened very quickly. We were continually looking for the traffic. I rolled the aircraft slightly to the left to change the window position. The sun was fairly low on the horizon and we weren't sure of the exact clock location of the traffic. Immediately after rolling left we received a TA with the target now at 6-7 NM and only 600 ft above us. This was almost immediately followed by a RA descend, descend command of 1200-1500 FPM. Just after I initiated the descent the captain visually acquired the traffic at about 1-1:30 O'clock position. It was directly in the sun from my view point and hidden by the window frame of the aircraft. Even though I had moved my head and the aircraft I was unable to see the traffic until the aircraft passed overhead. We descended from 5000 ft to 4400 ft at which time we received a monitor vertical speed. Approach control never called this traffic out to us. We told them that without TCASII it would have been a near midair collision. My observations from this event: first I was uncomfortable seeing a traffic threat and not really being able to do anything about it until TCASII gives us an avoidance maneuver. As an ex-fighter pilot I want to move the aircraft to miss the traffic horizontal not just vertical. Procedure says we shouldn't do this. I think this is wrong we need that capability. We didn't have time to query approach control about the traffic. From the time we recognized it as a treat and the RA was made was less than 15 seconds. During this time we are visually trying to find the traffic. Second TCASII needs to be integrated with some air to air radar capability that will give us better target azimuth. This case the traffic was 10-15 off from where we actually finally saw it. I notice TCASII does trail the acfts actual location. Also knowing closure rate of traffic will also help. Radar would do this. TCASII worked in this situation and probably saved a near midair collision.

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Original NASA ASRS Text

Title: ACR X TCASII TA RA EVASIVE ACTION TAKEN DSCNT AND TURN NON ADHERENCE TO ATC CLRNC. POSSIBLE LTSS FROM ACR Y. POSSIBLE SYS ERROR.

Narrative: ACR X ROA TO RIC. WHILE ON A VECTOR TO A VISUAL STRAIGHT IN TO RWY 02 A NEAR MISS OCCURRED WITH ACR Y, LTT. THE REASON NO COLLISION OCCURRED WAS A DIRECT RESULT OF TCASII. RICHMOND APCH CTL HAD ASSIGNED US A HDG OF 150 DEG AT 5000 MSL AND 210 KIAS. WE HAD OUR TCASII ON 10 NM SCOPE AND BELOW RA/TA. I WAS FLYING THE ACFT (FO) ON AUTOPLT. I NOTICED A CONFLICT WITH A TARGET ON THE SCOPE WHICH WAS ABOUT 15-20 DEGS R OF CTR AND SHOWING 800-900 FT ABOVE US IN A DSCNT. AS I MENTIONED IT TO THE CAPT WE WATCHED IT FOR NO MORE THAN A FEW SECONDS IN ORDER TO GET SOME SORT OF IDEA ON ITS TRACK, WE SAW THAT IT WAS DEFINITELY GOING TO BE A CONFLICT SO I TOOK THE ACFT OFF OF AUTOPLT. FROM THIS POINT THINGS HAPPENED VERY QUICKLY. WE WERE CONTINUALLY LOOKING FOR THE TFC. I ROLLED THE ACFT SLIGHTLY TO THE L TO CHANGE THE WINDOW POS. THE SUN WAS FAIRLY LOW ON THE HORIZON AND WE WEREN'T SURE OF THE EXACT CLOCK LOCATION OF THE TFC. IMMEDIATELY AFTER ROLLING L WE RECEIVED A TA WITH THE TARGET NOW AT 6-7 NM AND ONLY 600 FT ABOVE US. THIS WAS ALMOST IMMEDIATELY FOLLOWED BY A RA DSND, DSND COMMAND OF 1200-1500 FPM. JUST AFTER I INITIATED THE DSCNT THE CAPT VISUALLY ACQUIRED THE TFC AT ABOUT 1-1:30 O'CLOCK POS. IT WAS DIRECTLY IN THE SUN FROM MY VIEW POINT AND HIDDEN BY THE WINDOW FRAME OF THE ACFT. EVEN THOUGH I HAD MOVED MY HEAD AND THE ACFT I WAS UNABLE TO SEE THE TFC UNTIL THE ACFT PASSED OVERHEAD. WE DSNDED FROM 5000 FT TO 4400 FT AT WHICH TIME WE RECEIVED A MONITOR VERT SPD. APCH CTL NEVER CALLED THIS TFC OUT TO US. WE TOLD THEM THAT WITHOUT TCASII IT WOULD HAVE BEEN A NMAC. MY OBSERVATIONS FROM THIS EVENT: FIRST I WAS UNCOMFORTABLE SEEING A TFC THREAT AND NOT REALLY BEING ABLE TO DO ANYTHING ABOUT IT UNTIL TCASII GIVES US AN AVOIDANCE MANEUVER. AS AN EX-FIGHTER PLT I WANT TO MOVE THE ACFT TO MISS THE TFC HORIZ NOT JUST VERT. PROC SAYS WE SHOULDN'T DO THIS. I THINK THIS IS WRONG WE NEED THAT CAPABILITY. WE DIDN'T HAVE TIME TO QUERY APCH CTL ABOUT THE TFC. FROM THE TIME WE RECOGNIZED IT AS A TREAT AND THE RA WAS MADE WAS LESS THAN 15 SECONDS. DURING THIS TIME WE ARE VISUALLY TRYING TO FIND THE TFC. SECOND TCASII NEEDS TO BE INTEGRATED WITH SOME AIR TO AIR RADAR CAPABILITY THAT WILL GIVE US BETTER TARGET AZIMUTH. THIS CASE THE TFC WAS 10-15 OFF FROM WHERE WE ACTUALLY FINALLY SAW IT. I NOTICE TCASII DOES TRAIL THE ACFTS ACTUAL LOCATION. ALSO KNOWING CLOSURE RATE OF TFC WILL ALSO HELP. RADAR WOULD DO THIS. TCASII WORKED IN THIS SITUATION AND PROBABLY SAVED A NMAC.

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.