Narrative:

While on final approach to one of the parallel runways, I observed an aircraft pass under my aircraft with approximately 200 ft of clearance. Both aircraft were in class C airspace under control and contact with the tower. My approach was stabilized and properly positioned for the runway I was using. It turned out that the other aircraft's pilot got confused, and blew through the approach leg of the runway she was closed for, and then passed under our aircraft. Unfortunately, I not only had an additional pilot in the aircraft, but neither of us spotted the aircraft until after it had passed under our aircraft and out the other side. From a CRM standpoint, the pilot flying with me was doing an excellent job of helping keep the cockpit sterile and properly diverted. In other words, we were concentrating on flying the aircraft and we were doing a good job of maintaining situational awareness at all times. The situation could have been avoided if the other pilot had properly studied the airport layout and queried the tower about any confusion she had. Although we took immediate evasive maneuvers after seeing the other aircraft, had the other aircraft been closer vertically, there might have been a different outcome. In addition to the other pilot's improper approach, the tower controllers were not maintaining vigilance with monitoring the approaching aircraft. After the incident, I queried ATC about the other aircraft, and they were unaware of its position I believe the contributing factors to this situation were: 1) the other pilot's improper decision making during approach, 2) the other pilot's lack of preflight planning with respect to airport layout, 3) out lack of visual scanning vigilance, 4) the lack of the controllers to maintain contact and monitoring of the aircraft approach. As far as our lack of scanning vigilance, we were working hard on watching for other aircraft, but at the time of this situation, we were concentrating on watching the spacing with aircraft in front and to the side opposite from which the other aircraft approached. In other words, we were concentrating mainly on the aircraft in our pattern, and not the aircraft in the pattern of the other parallel runway.

Related reports:

Google
 

Original NASA ASRS Text

Title: ACFT ON FINAL APCH HAD ANOTHER ACFT PASS DIRECTLY BELOW WHILE IN CONTACT WITH THE TWR.

Narrative: WHILE ON FINAL APCH TO ONE OF THE PARALLEL RWYS, I OBSERVED AN ACFT PASS UNDER MY ACFT WITH APPROX 200 FT OF CLRNC. BOTH ACFT WERE IN CLASS C AIRSPACE UNDER CTL AND CONTACT WITH THE TWR. MY APCH WAS STABILIZED AND PROPERLY POSITIONED FOR THE RWY I WAS USING. IT TURNED OUT THAT THE OTHER ACFT'S PLT GOT CONFUSED, AND BLEW THROUGH THE APCH LEG OF THE RWY SHE WAS CLOSED FOR, AND THEN PASSED UNDER OUR ACFT. UNFORTUNATELY, I NOT ONLY HAD AN ADDITIONAL PLT IN THE ACFT, BUT NEITHER OF US SPOTTED THE ACFT UNTIL AFTER IT HAD PASSED UNDER OUR ACFT AND OUT THE OTHER SIDE. FROM A CRM STANDPOINT, THE PLT FLYING WITH ME WAS DOING AN EXCELLENT JOB OF HELPING KEEP THE COCKPIT STERILE AND PROPERLY DIVERTED. IN OTHER WORDS, WE WERE CONCENTRATING ON FLYING THE ACFT AND WE WERE DOING A GOOD JOB OF MAINTAINING SITUATIONAL AWARENESS AT ALL TIMES. THE SIT COULD HAVE BEEN AVOIDED IF THE OTHER PLT HAD PROPERLY STUDIED THE ARPT LAYOUT AND QUERIED THE TWR ABOUT ANY CONFUSION SHE HAD. ALTHOUGH WE TOOK IMMEDIATE EVASIVE MANEUVERS AFTER SEEING THE OTHER ACFT, HAD THE OTHER ACFT BEEN CLOSER VERTLY, THERE MIGHT HAVE BEEN A DIFFERENT OUTCOME. IN ADDITION TO THE OTHER PLT'S IMPROPER APCH, THE TWR CTLRS WERE NOT MAINTAINING VIGILANCE WITH MONITORING THE APCHING ACFT. AFTER THE INCIDENT, I QUERIED ATC ABOUT THE OTHER ACFT, AND THEY WERE UNAWARE OF ITS POS I BELIEVE THE CONTRIBUTING FACTORS TO THIS SIT WERE: 1) THE OTHER PLT'S IMPROPER DECISION MAKING DURING APCH, 2) THE OTHER PLT'S LACK OF PREFLT PLANNING WITH RESPECT TO ARPT LAYOUT, 3) OUT LACK OF VISUAL SCANNING VIGILANCE, 4) THE LACK OF THE CTLRS TO MAINTAIN CONTACT AND MONITORING OF THE ACFT APCH. AS FAR AS OUR LACK OF SCANNING VIGILANCE, WE WERE WORKING HARD ON WATCHING FOR OTHER ACFT, BUT AT THE TIME OF THIS SIT, WE WERE CONCENTRATING ON WATCHING THE SPACING WITH ACFT IN FRONT AND TO THE SIDE OPPOSITE FROM WHICH THE OTHER ACFT APCHED. IN OTHER WORDS, WE WERE CONCENTRATING MAINLY ON THE ACFT IN OUR PATTERN, AND NOT THE ACFT IN THE PATTERN OF THE OTHER PARALLEL RWY.

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.