Narrative:

While on radar vectors for an ILS approach to runway 10L at cmh, we had 2 near misses occur within a few seconds of each other. Events developed quickly, so the sequence may be in error. Parallel approachs to runways 10L and 10R were in use in cmh. We had been assigned runway 10L. All navaids had been tuned and idented and an approach briefing completed. The TCASII had also been tested earlier and was operating normally in TA/RA. The first officer as the PF and the autoplt/flight director was in use in heading and altitude modes. Our initial heading for the approach to runway 10L was 230 degrees which would take us to the northwest of grens NDB. We had descended to 4000 ft and assigned a heading of 270 degrees. During the initial radar vectors, the TCASII was operating on the 12 mi scale. There were approximately 3 aircraft displayed on the TCASII display. I would describe the controller's workload as moderate. At about 13 DME icbp w-nw, we were assigned a heading of 180 degrees again at 4000 ft. This placed an aircraft at approximately our 1:30 O'clock position for 3 mi and 4000 ft. As the initial conflict developed, I thought that this aircraft may already be on the runway 10L localizer and he would pass in front of us. We then received a TA for that traffic. ATC then issued a right turn to 300 degrees. As we started our turn we received a preventive RA, 'monitor vertical speed,' with the scale on the vsi showing red below zero. The autoplt was disconnected and we started a gentle climb to 4200 ft as a light twin passed just below the first officer's side window. As we passed through heading 210 degrees, the controller asked our heading and gave us a left turn to 080 degrees. As we started the turn back, we received a corrective RA, 'climb, climb' or 'climb, climb now.' the vsi showed red from +2000 FPM and below. We complied with the RA but did not acquire the second target. The maximum altitude reached during RA was 4700 ft. The controller reissued a turn to 080 degrees heading and cleared us for an ILS to runway 10L. We landed without incident. I noticed on the TCASII display that the white 'own aircraft' symbol superimposed over the RA target makes the target very difficult to see. The 'own aircraft' symbol and the orientation marks are dominant versus the RA target and its data tail. Both the proximity and TA traffic symbols are more discernible against the display's dark background. Callback conversation with reporter revealed the following information: the reporter was in IMC during both of these encounters. These were not false alarms, he saw the first aircraft about 200 ft away. The second encounter was caused when the reporter was given a turn and climbed in response to the TA. There was a loss of separation, but the reporter did not see the other aircraft. The separation was described as being either 0.25 mi or 2.5 mi, less than standard separation. The reporter called the TRACON supervisor immediately when on the ground. The supervisor admitted that the first incident was 'controller error' and the second was the result of the first incident. The reporter and his first officer both 'logged off' of the trip as soon as they got on the ground. Their air carrier and pilot's union have been very supportive of the crew.

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Original NASA ASRS Text

Title: A DHC8 CREW HAD AN NMAC, THEN LTSS WITH 2 DIFFERENT ACFT WHILE IMC.

Narrative: WHILE ON RADAR VECTORS FOR AN ILS APCH TO RWY 10L AT CMH, WE HAD 2 NEAR MISSES OCCUR WITHIN A FEW SECONDS OF EACH OTHER. EVENTS DEVELOPED QUICKLY, SO THE SEQUENCE MAY BE IN ERROR. PARALLEL APCHS TO RWYS 10L AND 10R WERE IN USE IN CMH. WE HAD BEEN ASSIGNED RWY 10L. ALL NAVAIDS HAD BEEN TUNED AND IDENTED AND AN APCH BRIEFING COMPLETED. THE TCASII HAD ALSO BEEN TESTED EARLIER AND WAS OPERATING NORMALLY IN TA/RA. THE FO AS THE PF AND THE AUTOPLT/FLT DIRECTOR WAS IN USE IN HDG AND ALT MODES. OUR INITIAL HDG FOR THE APCH TO RWY 10L WAS 230 DEGS WHICH WOULD TAKE US TO THE NW OF GRENS NDB. WE HAD DSNDED TO 4000 FT AND ASSIGNED A HDG OF 270 DEGS. DURING THE INITIAL RADAR VECTORS, THE TCASII WAS OPERATING ON THE 12 MI SCALE. THERE WERE APPROX 3 ACFT DISPLAYED ON THE TCASII DISPLAY. I WOULD DESCRIBE THE CTLR'S WORKLOAD AS MODERATE. AT ABOUT 13 DME ICBP W-NW, WE WERE ASSIGNED A HDG OF 180 DEGS AGAIN AT 4000 FT. THIS PLACED AN ACFT AT APPROX OUR 1:30 O'CLOCK POS FOR 3 MI AND 4000 FT. AS THE INITIAL CONFLICT DEVELOPED, I THOUGHT THAT THIS ACFT MAY ALREADY BE ON THE RWY 10L LOC AND HE WOULD PASS IN FRONT OF US. WE THEN RECEIVED A TA FOR THAT TFC. ATC THEN ISSUED A R TURN TO 300 DEGS. AS WE STARTED OUR TURN WE RECEIVED A PREVENTIVE RA, 'MONITOR VERT SPD,' WITH THE SCALE ON THE VSI SHOWING RED BELOW ZERO. THE AUTOPLT WAS DISCONNECTED AND WE STARTED A GENTLE CLB TO 4200 FT AS A LIGHT TWIN PASSED JUST BELOW THE FO'S SIDE WINDOW. AS WE PASSED THROUGH HDG 210 DEGS, THE CTLR ASKED OUR HDG AND GAVE US A L TURN TO 080 DEGS. AS WE STARTED THE TURN BACK, WE RECEIVED A CORRECTIVE RA, 'CLB, CLB' OR 'CLB, CLB NOW.' THE VSI SHOWED RED FROM +2000 FPM AND BELOW. WE COMPLIED WITH THE RA BUT DID NOT ACQUIRE THE SECOND TARGET. THE MAX ALT REACHED DURING RA WAS 4700 FT. THE CTLR REISSUED A TURN TO 080 DEGS HDG AND CLRED US FOR AN ILS TO RWY 10L. WE LANDED WITHOUT INCIDENT. I NOTICED ON THE TCASII DISPLAY THAT THE WHITE 'OWN ACFT' SYMBOL SUPERIMPOSED OVER THE RA TARGET MAKES THE TARGET VERY DIFFICULT TO SEE. THE 'OWN ACFT' SYMBOL AND THE ORIENTATION MARKS ARE DOMINANT VERSUS THE RA TARGET AND ITS DATA TAIL. BOTH THE PROX AND TA TFC SYMBOLS ARE MORE DISCERNIBLE AGAINST THE DISPLAY'S DARK BACKGROUND. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR WAS IN IMC DURING BOTH OF THESE ENCOUNTERS. THESE WERE NOT FALSE ALARMS, HE SAW THE FIRST ACFT ABOUT 200 FT AWAY. THE SECOND ENCOUNTER WAS CAUSED WHEN THE RPTR WAS GIVEN A TURN AND CLBED IN RESPONSE TO THE TA. THERE WAS A LOSS OF SEPARATION, BUT THE RPTR DID NOT SEE THE OTHER ACFT. THE SEPARATION WAS DESCRIBED AS BEING EITHER 0.25 MI OR 2.5 MI, LTSS. THE RPTR CALLED THE TRACON SUPVR IMMEDIATELY WHEN ON THE GND. THE SUPVR ADMITTED THAT THE FIRST INCIDENT WAS 'CTLR ERROR' AND THE SECOND WAS THE RESULT OF THE FIRST INCIDENT. THE RPTR AND HIS FO BOTH 'LOGGED OFF' OF THE TRIP AS SOON AS THEY GOT ON THE GND. THEIR ACR AND PLT'S UNION HAVE BEEN VERY SUPPORTIVE OF THE CREW.

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.