Narrative:

We were medium large transport X from sjc to den on final approach to runway 17R. After changing over to tower frequency, about 5 mi out, we were cleared to land on runway 17R. We were following medium large transport Y who was on short final when we were cleared to land. Medium large transport Z was following us on the approach. It was just after dark, but other than that, visibility was not a problem. We were aligned with the runway and on the VASI descent slope from at least 5 mi out. Den tower was also working an medium large transport D on our frequency for runway 18. We heard several xmissions to that flight in relation to runway 18. Runway 17L was also in use at the time. Neither the first officer nor myself heard any clearance to land on runway 17R for medium large transport D. We scanned the probable pattern area for runway 18, but sighted nothing. Den tower never pointed out any traffic or possible conflict to us in relation to medium large transport D for runway 18. During a conversation later in flight operations with the first officer of medium large transport Z, which followed us on the approach, he said they sighted what they first thought was ground traffic (because of its low altitude) coming across from the area of runway 18 over to runway 17R. He said it looked to them as if the aircraft turned in on final to runway 17R behind our flight. He also said they heard the tower calls to that aircraft in relation to runway 18, but no clearance to land on 17R. At 200' AGL my first officer saw the traffic coming straight in from our right. He called out the traffic and as I saw the aircraft it was making a radical climbing turn to the right. We both estimate that he missed our right wing by 50-100' as he turned away. At the time, all our landing and navigation lights were on. I had turned on the outboard landing lights at about 500' AGL. These additional lights coming on may have alerted the other aircraft to our position. He probably was maintaining his altitude, after losing altitude for runway 18,and was probably looking downward and to his right to land on runway 17R as we approached from his left and above him. Our speed would have brought us up on his position (as he was flying on a modified base leg) very rapidly. Also our altitudes would have almost had to be the same before he could have seen us without looking up and to his left. We did not have time to take evasive action and if he had not sighted us in time to turn we would have collided. Our trying to turn or climb may have even put our right wing into closer proximity to him. After he turned away, the tower asked if he could still land on runway 18 and he said he could if he was given a 360 degree turn back to a final. I reported the near miss to the controller and called the tower from flight operations. The tower supervisor told me the other aircraft was medium large transport D operated by company a. He said that the tower controller had cleared that aircraft to land on runway 17R in error. This was shown by a review of the voice tape. We never heard that clearance, but we could have been making our standard SOP callouts in the cockpit at the time. I asked if it was possible to hear the voice tape and he said he didn't know if that was possible. I think the practice of clearing one flight to land while the flight ahead is still in the air, or not off the runway, is a factor in this near miss. Because of the position of our aircraft and the flight path of the other aircraft, I don't believe he was possible to see from the left side of the cockpit until our altitudes matched. The first officer flying was necessarily busy with other things on short final and would have had to look down and close in to have seen it. All traffic for parallel apches should be called out by the tower. I will try to visually scan the lower altitudes on apches because of this experience, but again I do not believe it would have helped in this instance. Please make known to me any information that might have prevented this near miss and I would especially like to know when in our approach that the other aircraft was cleared to land on our runway.

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Original NASA ASRS Text

Title: ACFT X ON APCH TO RWY 17R AT DEN HAS NMAC WITH ACFT D ORIGINALLY CLEARED TO LAND ON RWY 18, BUT SWITCHED TO RWY 17R BY TWR CTLR. ACFT D TAKES EVASIVE ACTION TO AVOID MIDAIR COLLISION. TWR SUPVR ADMITS 'MISTAKE' OF CTLR IN CLEARING ACFT D TO LAND ON RWY 17R.

Narrative: WE WERE MLG X FROM SJC TO DEN ON FINAL APCH TO RWY 17R. AFTER CHANGING OVER TO TWR FREQ, ABOUT 5 MI OUT, WE WERE CLRED TO LAND ON RWY 17R. WE WERE FOLLOWING MLG Y WHO WAS ON SHORT FINAL WHEN WE WERE CLRED TO LAND. MLG Z WAS FOLLOWING US ON THE APCH. IT WAS JUST AFTER DARK, BUT OTHER THAN THAT, VISIBILITY WAS NOT A PROBLEM. WE WERE ALIGNED WITH THE RWY AND ON THE VASI DSCNT SLOPE FROM AT LEAST 5 MI OUT. DEN TWR WAS ALSO WORKING AN MLG D ON OUR FREQ FOR RWY 18. WE HEARD SEVERAL XMISSIONS TO THAT FLT IN RELATION TO RWY 18. RWY 17L WAS ALSO IN USE AT THE TIME. NEITHER THE F/O NOR MYSELF HEARD ANY CLRNC TO LAND ON RWY 17R FOR MLG D. WE SCANNED THE PROBABLE PATTERN AREA FOR RWY 18, BUT SIGHTED NOTHING. DEN TWR NEVER POINTED OUT ANY TFC OR POSSIBLE CONFLICT TO US IN RELATION TO MLG D FOR RWY 18. DURING A CONVERSATION LATER IN FLT OPERATIONS WITH THE F/O OF MLG Z, WHICH FOLLOWED US ON THE APCH, HE SAID THEY SIGHTED WHAT THEY FIRST THOUGHT WAS GND TFC (BECAUSE OF ITS LOW ALT) COMING ACROSS FROM THE AREA OF RWY 18 OVER TO RWY 17R. HE SAID IT LOOKED TO THEM AS IF THE ACFT TURNED IN ON FINAL TO RWY 17R BEHIND OUR FLT. HE ALSO SAID THEY HEARD THE TWR CALLS TO THAT ACFT IN RELATION TO RWY 18, BUT NO CLRNC TO LAND ON 17R. AT 200' AGL MY F/O SAW THE TFC COMING STRAIGHT IN FROM OUR RIGHT. HE CALLED OUT THE TFC AND AS I SAW THE ACFT IT WAS MAKING A RADICAL CLIMBING TURN TO THE RIGHT. WE BOTH ESTIMATE THAT HE MISSED OUR RIGHT WING BY 50-100' AS HE TURNED AWAY. AT THE TIME, ALL OUR LNDG AND NAVIGATION LIGHTS WERE ON. I HAD TURNED ON THE OUTBOARD LNDG LIGHTS AT ABOUT 500' AGL. THESE ADDITIONAL LIGHTS COMING ON MAY HAVE ALERTED THE OTHER ACFT TO OUR POSITION. HE PROBABLY WAS MAINTAINING HIS ALT, AFTER LOSING ALT FOR RWY 18,AND WAS PROBABLY LOOKING DOWNWARD AND TO HIS RIGHT TO LAND ON RWY 17R AS WE APCHED FROM HIS LEFT AND ABOVE HIM. OUR SPEED WOULD HAVE BROUGHT US UP ON HIS POSITION (AS HE WAS FLYING ON A MODIFIED BASE LEG) VERY RAPIDLY. ALSO OUR ALTS WOULD HAVE ALMOST HAD TO BE THE SAME BEFORE HE COULD HAVE SEEN US WITHOUT LOOKING UP AND TO HIS LEFT. WE DID NOT HAVE TIME TO TAKE EVASIVE ACTION AND IF HE HAD NOT SIGHTED US IN TIME TO TURN WE WOULD HAVE COLLIDED. OUR TRYING TO TURN OR CLIMB MAY HAVE EVEN PUT OUR RIGHT WING INTO CLOSER PROX TO HIM. AFTER HE TURNED AWAY, THE TWR ASKED IF HE COULD STILL LAND ON RWY 18 AND HE SAID HE COULD IF HE WAS GIVEN A 360 DEG TURN BACK TO A FINAL. I REPORTED THE NEAR MISS TO THE CTLR AND CALLED THE TWR FROM FLT OPERATIONS. THE TWR SUPVR TOLD ME THE OTHER ACFT WAS MLG D OPERATED BY COMPANY A. HE SAID THAT THE TWR CTLR HAD CLRED THAT ACFT TO LAND ON RWY 17R IN ERROR. THIS WAS SHOWN BY A REVIEW OF THE VOICE TAPE. WE NEVER HEARD THAT CLRNC, BUT WE COULD HAVE BEEN MAKING OUR STANDARD SOP CALLOUTS IN THE COCKPIT AT THE TIME. I ASKED IF IT WAS POSSIBLE TO HEAR THE VOICE TAPE AND HE SAID HE DIDN'T KNOW IF THAT WAS POSSIBLE. I THINK THE PRACTICE OF CLEARING ONE FLT TO LAND WHILE THE FLT AHEAD IS STILL IN THE AIR, OR NOT OFF THE RWY, IS A FACTOR IN THIS NEAR MISS. BECAUSE OF THE POSITION OF OUR ACFT AND THE FLT PATH OF THE OTHER ACFT, I DON'T BELIEVE HE WAS POSSIBLE TO SEE FROM THE LEFT SIDE OF THE COCKPIT UNTIL OUR ALTS MATCHED. THE F/O FLYING WAS NECESSARILY BUSY WITH OTHER THINGS ON SHORT FINAL AND WOULD HAVE HAD TO LOOK DOWN AND CLOSE IN TO HAVE SEEN IT. ALL TFC FOR PARALLEL APCHES SHOULD BE CALLED OUT BY THE TWR. I WILL TRY TO VISUALLY SCAN THE LOWER ALTS ON APCHES BECAUSE OF THIS EXPERIENCE, BUT AGAIN I DO NOT BELIEVE IT WOULD HAVE HELPED IN THIS INSTANCE. PLEASE MAKE KNOWN TO ME ANY INFO THAT MIGHT HAVE PREVENTED THIS NEAR MISS AND I WOULD ESPECIALLY LIKE TO KNOW WHEN IN OUR APCH THAT THE OTHER ACFT WAS CLRED TO LAND ON OUR RWY.

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.