Narrative:

We were approximately 15 mi east of monroe inbound for landing when mlu approach control called out traffic in our 12 O'clock that was climbing to 4000 ft assigned. (We both were under mlu approach control.) we were level at 5000 ft and initially observed this aircraft on TCASII climbing through 2800 ft. We watched as he climbed through 4200 ft at which time we received a TCASII RA which commanded a 2000 FPM climb. I cannot verify separation either vertically or horizontally as we never did visually see the approaching traffic. We followed the TCASII RA, climbing to 6000 ft, reported our deviation from assigned altitude and then returned to 5000 ft when the traffic had passed beneath us. Monroe had only a few aircraft to control at this time. I question their decision to run 2 aircraft head-on with only 1000 ft separation. Perhaps we should have asked for a vector, but our attention was on our approach and the thunderstorms that were complicating it. Time was a factor as we had little warning. One comment about our TCASII. It was equipped with the flight level circuitry that allows depiction of actual target aircraft altitude below 18000 ft as opposed to deviation from host aircraft altitude. I find the former easier to interpolate quickly. Supplemental information from acn 247331: after departing mlu I was to maintain 4000 ft. Prior to reaching this altitude I was given a TA for traffic descending for mlu out of 5000 ft, an medium large transport. As I was climbing through 3800 ft and looking for the traffic, the medium large transport wingtip landing lights and nose section came into view out of the clouds. The aircraft appeared to be at or very near my altitude and closing rapidly. I felt that evasive action would be necessary in the form of a climb since I was already climbing and the medium large transport appeared in a descent for the airport. I continued climbing to 4200 ft and could tell by this time the medium large transport would pass above me and I could also tell the captain of the medium large transport had added power and started a pitch up of the nose of the aircraft to begin evasive action himself, so I dropped the nose of my aircraft upon seeing this and went back to my altitude assignment. I knew I could avoid a collision with the medium large transport but I did not understand why 2 aircraft, 1 leaving the airport and 1 arriving, had to be brought so close horizontally and then to have only 1000 ft vertical separation between both in marginal conditions with thunderstorms in the immediate area to the northeast. I feel that this separation criteria is not sufficient to provide maximum safety during aircraft operations, especially in reduced visibility. If the vertical separation can't be widened, then a controller with vectoring instructions could have moved these aircraft away from each other.

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Original NASA ASRS Text

Title: ALTDEV ALT EXCURSION AFTER RECEIVING TCASII RA DURING APCH.

Narrative: WE WERE APPROX 15 MI E OF MONROE INBOUND FOR LNDG WHEN MLU APCH CTL CALLED OUT TFC IN OUR 12 O'CLOCK THAT WAS CLBING TO 4000 FT ASSIGNED. (WE BOTH WERE UNDER MLU APCH CTL.) WE WERE LEVEL AT 5000 FT AND INITIALLY OBSERVED THIS ACFT ON TCASII CLBING THROUGH 2800 FT. WE WATCHED AS HE CLBED THROUGH 4200 FT AT WHICH TIME WE RECEIVED A TCASII RA WHICH COMMANDED A 2000 FPM CLB. I CANNOT VERIFY SEPARATION EITHER VERTICALLY OR HORIZLY AS WE NEVER DID VISUALLY SEE THE APCHING TFC. WE FOLLOWED THE TCASII RA, CLBING TO 6000 FT, RPTED OUR DEV FROM ASSIGNED ALT AND THEN RETURNED TO 5000 FT WHEN THE TFC HAD PASSED BENEATH US. MONROE HAD ONLY A FEW ACFT TO CTL AT THIS TIME. I QUESTION THEIR DECISION TO RUN 2 ACFT HEAD-ON WITH ONLY 1000 FT SEPARATION. PERHAPS WE SHOULD HAVE ASKED FOR A VECTOR, BUT OUR ATTN WAS ON OUR APCH AND THE TSTMS THAT WERE COMPLICATING IT. TIME WAS A FACTOR AS WE HAD LITTLE WARNING. ONE COMMENT ABOUT OUR TCASII. IT WAS EQUIPPED WITH THE FLT LEVEL CIRCUITRY THAT ALLOWS DEPICTION OF ACTUAL TARGET ACFT ALT BELOW 18000 FT AS OPPOSED TO DEV FROM HOST ACFT ALT. I FIND THE FORMER EASIER TO INTERPOLATE QUICKLY. SUPPLEMENTAL INFO FROM ACN 247331: AFTER DEPARTING MLU I WAS TO MAINTAIN 4000 FT. PRIOR TO REACHING THIS ALT I WAS GIVEN A TA FOR TFC DSNDING FOR MLU OUT OF 5000 FT, AN MLG. AS I WAS CLBING THROUGH 3800 FT AND LOOKING FOR THE TFC, THE MLG WINGTIP LNDG LIGHTS AND NOSE SECTION CAME INTO VIEW OUT OF THE CLOUDS. THE ACFT APPEARED TO BE AT OR VERY NEAR MY ALT AND CLOSING RAPIDLY. I FELT THAT EVASIVE ACTION WOULD BE NECESSARY IN THE FORM OF A CLB SINCE I WAS ALREADY CLBING AND THE MLG APPEARED IN A DSCNT FOR THE ARPT. I CONTINUED CLBING TO 4200 FT AND COULD TELL BY THIS TIME THE MLG WOULD PASS ABOVE ME AND I COULD ALSO TELL THE CAPT OF THE MLG HAD ADDED PWR AND STARTED A PITCH UP OF THE NOSE OF THE ACFT TO BEGIN EVASIVE ACTION HIMSELF, SO I DROPPED THE NOSE OF MY ACFT UPON SEEING THIS AND WENT BACK TO MY ALT ASSIGNMENT. I KNEW I COULD AVOID A COLLISION WITH THE MLG BUT I DID NOT UNDERSTAND WHY 2 ACFT, 1 LEAVING THE ARPT AND 1 ARRIVING, HAD TO BE BROUGHT SO CLOSE HORIZLY AND THEN TO HAVE ONLY 1000 FT VERT SEPARATION BTWN BOTH IN MARGINAL CONDITIONS WITH TSTMS IN THE IMMEDIATE AREA TO THE NE. I FEEL THAT THIS SEPARATION CRITERIA IS NOT SUFFICIENT TO PROVIDE MAX SAFETY DURING ACFT OPS, ESPECIALLY IN REDUCED VISIBILITY. IF THE VERT SEPARATION CAN'T BE WIDENED, THEN A CTLR WITH VECTORING INSTRUCTIONS COULD HAVE MOVED THESE ACFT AWAY FROM EACH OTHER.

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.