Narrative:

Approaching the santa susana pass, I received ATIS information for the airport, and then proceeded to contact vny tower. I did not make an initial transmission until there was a break in the abnormally heavy activity. At the point I was able to communicate I was 11.9 NM from the airport. The controller was very busy, and gave me my transponder squawk code at the end of another transmission to clear an aircraft for landing on runway 16R. As to human factors, at this point, I turned to my instructor and suggested we call in and make sure the squawk was for us. He said he had heard the call as well, annunciated the squawk to me, and that we should just proceed. 'Technically' we had established the required dialog necessary for entering the class D airspace which we would be in shortly. I executed a normal descent immediately following the santa susana pass reporting point, going first from 3500 ft to 2500 ft to get below the class C floor. I reached 2500 ft about 1/2 NM from 'the college' which is a recognized reporting point. I had not heard from the controller again, though I did hear a lot of traffic on the radios. Upon reaching the college, I quickly reported our position and our altitude. At this point, I received a clear recognition of my call. I was told I was #3 for runway 16R, and I needed to make my best possible speed 'all the way to the runway.' (see illustration #1.) at the time, I thought this was an odd call -- we are less than 4 NM out on an extended base (right traffic), there are 2 planes ahead of us, and they asked us to go as fast as possible. Perhaps most significantly, we did not have either traffic in sight. In my call back, I confirmed best possible speed and announced that I was 'looking for traffic.' I discussed what 'best possible speed' would be with my instructor, and told him my concern that we were really close and if we kept 120 KTS that we could not lower even 1 notch of flaps. He just said to go with it, and we would ask to slow down on final. For the record, I don't think this would have worked anyway, as a no-flap landing takes a lot more maneuvering space than we were going to have. All of a sudden, we spotted traffic #1 ahead of us, who was on a straight-in final to runway 16R. (See illustration #2.) we would have sufficient spacing after them, however, that left the question of where the other traffic was. As it was almost time to turn final, I called in to report that we still did not have the other traffic in sight. As I looked to my left prior to the turn, I stopped in mid sentence on the radio as I saw a C172 on final. My instructor heard my warning, and then said 'my plane.' he deviated, so as to pass on the right side of the approaching plane, turning left, away from runway 16R, at about a heading of 360 degrees. The miss was at the same altitude, and the miss was less than 100 ft horizontal, wingtip-to-wingtip. (See illustration #3.) our further recovery was marred as a small single engine fixed gear of unknown type was in the 'east' pattern, and was cleared to land on runway 16L. (See illustration #4.) later conversations between my instructor and the tower indicated that this small training aircraft had overshot runway 16L on its base to final turn, and was headed more toward runway 16R. My instructor avoided this collision by taking evasive action to the left with approximately a 500 ft drop in altitude during the 180 degree turn. He then called the tower, and got clearance to land, and thanks for avoiding this. I don't feel comfortable assessing any blame, but it seems to me that there are a lot of human factors here worth discussing. First, the controller asked us to keep best possible speed to the runway when the opposite instruction was what was intended, or (though the controller thought this not to be the case in later discussion) was actually intended for someone already on final. Second, we were aware that the controller's workload was extraordinarily high and we should have asked for clarification when I first wanted to get it. Third, there were too many planes in the pattern to allow for safe operations, and the tolerances for overshoot may be too slim for vny, as runway 16L is used for initial flight training operations extensively, while runway 16R has a variety of traffic of all speeds and purposes. Fourth, I think our initial correction, though the only possibility to avoid the first collision, put us at high risk to interfere with other traffic. Fifth, during the course of the 11.9 NM from initial call in, no one on 119.30 (the tower has a second controller on 120.20 for the east pattern) had any traffic callouts. Therefore, none were confirmed. Sixth and finally, as minimal a factor as it may seem, I believe that call backs of squawk codes should never be omitted due to busy radio and traffic conditions. I think the whole problem may have originated when the controller was less than situationally aware of our position and ground speed in concordance with the standard approach we were planning to make. One last note: the controllers at vny do a fantastic job of handling many needs in a mixed environment. Hundreds of students combined with small to medium sized bizjets vie for these runways daily. Perhaps there should be some voluntary restraints (like no touch-and-goes on the wkends, or a maximum amount of times in the pattern, or a variation in the 'east' pattern), to help them do their job. The controllers at the tower have gone out of their way to do things like host programs to get familiar with the tower (which I have attended), and really take care of those who are soloing for the first time, along with getting clrncs for those who have to travel through the busy los angeles corridor. Reducing their workload would keep everything safer for everyone.

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Original NASA ASRS Text

Title: A STUDENT PLT RPT ON EXPERIENCING 2 NMAC'S ON 1 VISUAL APCH TO VNY, CA.

Narrative: APCHING THE SANTA SUSANA PASS, I RECEIVED ATIS INFO FOR THE ARPT, AND THEN PROCEEDED TO CONTACT VNY TWR. I DID NOT MAKE AN INITIAL XMISSION UNTIL THERE WAS A BREAK IN THE ABNORMALLY HVY ACTIVITY. AT THE POINT I WAS ABLE TO COMMUNICATE I WAS 11.9 NM FROM THE ARPT. THE CTLR WAS VERY BUSY, AND GAVE ME MY XPONDER SQUAWK CODE AT THE END OF ANOTHER XMISSION TO CLR AN ACFT FOR LNDG ON RWY 16R. AS TO HUMAN FACTORS, AT THIS POINT, I TURNED TO MY INSTRUCTOR AND SUGGESTED WE CALL IN AND MAKE SURE THE SQUAWK WAS FOR US. HE SAID HE HAD HEARD THE CALL AS WELL, ANNUNCIATED THE SQUAWK TO ME, AND THAT WE SHOULD JUST PROCEED. 'TECHNICALLY' WE HAD ESTABLISHED THE REQUIRED DIALOG NECESSARY FOR ENTERING THE CLASS D AIRSPACE WHICH WE WOULD BE IN SHORTLY. I EXECUTED A NORMAL DSCNT IMMEDIATELY FOLLOWING THE SANTA SUSANA PASS RPTING POINT, GOING FIRST FROM 3500 FT TO 2500 FT TO GET BELOW THE CLASS C FLOOR. I REACHED 2500 FT ABOUT 1/2 NM FROM 'THE COLLEGE' WHICH IS A RECOGNIZED RPTING POINT. I HAD NOT HEARD FROM THE CTLR AGAIN, THOUGH I DID HEAR A LOT OF TFC ON THE RADIOS. UPON REACHING THE COLLEGE, I QUICKLY RPTED OUR POS AND OUR ALT. AT THIS POINT, I RECEIVED A CLR RECOGNITION OF MY CALL. I WAS TOLD I WAS #3 FOR RWY 16R, AND I NEEDED TO MAKE MY BEST POSSIBLE SPD 'ALL THE WAY TO THE RWY.' (SEE ILLUSTRATION #1.) AT THE TIME, I THOUGHT THIS WAS AN ODD CALL -- WE ARE LESS THAN 4 NM OUT ON AN EXTENDED BASE (R TFC), THERE ARE 2 PLANES AHEAD OF US, AND THEY ASKED US TO GO AS FAST AS POSSIBLE. PERHAPS MOST SIGNIFICANTLY, WE DID NOT HAVE EITHER TFC IN SIGHT. IN MY CALL BACK, I CONFIRMED BEST POSSIBLE SPD AND ANNOUNCED THAT I WAS 'LOOKING FOR TFC.' I DISCUSSED WHAT 'BEST POSSIBLE SPD' WOULD BE WITH MY INSTRUCTOR, AND TOLD HIM MY CONCERN THAT WE WERE REALLY CLOSE AND IF WE KEPT 120 KTS THAT WE COULD NOT LOWER EVEN 1 NOTCH OF FLAPS. HE JUST SAID TO GO WITH IT, AND WE WOULD ASK TO SLOW DOWN ON FINAL. FOR THE RECORD, I DON'T THINK THIS WOULD HAVE WORKED ANYWAY, AS A NO-FLAP LNDG TAKES A LOT MORE MANEUVERING SPACE THAN WE WERE GOING TO HAVE. ALL OF A SUDDEN, WE SPOTTED TFC #1 AHEAD OF US, WHO WAS ON A STRAIGHT-IN FINAL TO RWY 16R. (SEE ILLUSTRATION #2.) WE WOULD HAVE SUFFICIENT SPACING AFTER THEM, HOWEVER, THAT LEFT THE QUESTION OF WHERE THE OTHER TFC WAS. AS IT WAS ALMOST TIME TO TURN FINAL, I CALLED IN TO RPT THAT WE STILL DID NOT HAVE THE OTHER TFC IN SIGHT. AS I LOOKED TO MY L PRIOR TO THE TURN, I STOPPED IN MID SENTENCE ON THE RADIO AS I SAW A C172 ON FINAL. MY INSTRUCTOR HEARD MY WARNING, AND THEN SAID 'MY PLANE.' HE DEVIATED, SO AS TO PASS ON THE R SIDE OF THE APCHING PLANE, TURNING L, AWAY FROM RWY 16R, AT ABOUT A HDG OF 360 DEGS. THE MISS WAS AT THE SAME ALT, AND THE MISS WAS LESS THAN 100 FT HORIZ, WINGTIP-TO-WINGTIP. (SEE ILLUSTRATION #3.) OUR FURTHER RECOVERY WAS MARRED AS A SMALL SINGLE ENG FIXED GEAR OF UNKNOWN TYPE WAS IN THE 'E' PATTERN, AND WAS CLRED TO LAND ON RWY 16L. (SEE ILLUSTRATION #4.) LATER CONVERSATIONS BTWN MY INSTRUCTOR AND THE TWR INDICATED THAT THIS SMALL TRAINING ACFT HAD OVERSHOT RWY 16L ON ITS BASE TO FINAL TURN, AND WAS HEADED MORE TOWARD RWY 16R. MY INSTRUCTOR AVOIDED THIS COLLISION BY TAKING EVASIVE ACTION TO THE L WITH APPROX A 500 FT DROP IN ALT DURING THE 180 DEG TURN. HE THEN CALLED THE TWR, AND GOT CLRNC TO LAND, AND THANKS FOR AVOIDING THIS. I DON'T FEEL COMFORTABLE ASSESSING ANY BLAME, BUT IT SEEMS TO ME THAT THERE ARE A LOT OF HUMAN FACTORS HERE WORTH DISCUSSING. FIRST, THE CTLR ASKED US TO KEEP BEST POSSIBLE SPD TO THE RWY WHEN THE OPPOSITE INSTRUCTION WAS WHAT WAS INTENDED, OR (THOUGH THE CTLR THOUGHT THIS NOT TO BE THE CASE IN LATER DISCUSSION) WAS ACTUALLY INTENDED FOR SOMEONE ALREADY ON FINAL. SECOND, WE WERE AWARE THAT THE CTLR'S WORKLOAD WAS EXTRAORDINARILY HIGH AND WE SHOULD HAVE ASKED FOR CLARIFICATION WHEN I FIRST WANTED TO GET IT. THIRD, THERE WERE TOO MANY PLANES IN THE PATTERN TO ALLOW FOR SAFE OPS, AND THE TOLERANCES FOR OVERSHOOT MAY BE TOO SLIM FOR VNY, AS RWY 16L IS USED FOR INITIAL FLT TRAINING OPS EXTENSIVELY, WHILE RWY 16R HAS A VARIETY OF TFC OF ALL SPDS AND PURPOSES. FOURTH, I THINK OUR INITIAL CORRECTION, THOUGH THE ONLY POSSIBILITY TO AVOID THE FIRST COLLISION, PUT US AT HIGH RISK TO INTERFERE WITH OTHER TFC. FIFTH, DURING THE COURSE OF THE 11.9 NM FROM INITIAL CALL IN, NO ONE ON 119.30 (THE TWR HAS A SECOND CTLR ON 120.20 FOR THE E PATTERN) HAD ANY TFC CALLOUTS. THEREFORE, NONE WERE CONFIRMED. SIXTH AND FINALLY, AS MINIMAL A FACTOR AS IT MAY SEEM, I BELIEVE THAT CALL BACKS OF SQUAWK CODES SHOULD NEVER BE OMITTED DUE TO BUSY RADIO AND TFC CONDITIONS. I THINK THE WHOLE PROB MAY HAVE ORIGINATED WHEN THE CTLR WAS LESS THAN SITUATIONALLY AWARE OF OUR POS AND GND SPD IN CONCORDANCE WITH THE STANDARD APCH WE WERE PLANNING TO MAKE. ONE LAST NOTE: THE CTLRS AT VNY DO A FANTASTIC JOB OF HANDLING MANY NEEDS IN A MIXED ENVIRONMENT. HUNDREDS OF STUDENTS COMBINED WITH SMALL TO MEDIUM SIZED BIZJETS VIE FOR THESE RWYS DAILY. PERHAPS THERE SHOULD BE SOME VOLUNTARY RESTRAINTS (LIKE NO TOUCH-AND-GOES ON THE WKENDS, OR A MAX AMOUNT OF TIMES IN THE PATTERN, OR A VARIATION IN THE 'E' PATTERN), TO HELP THEM DO THEIR JOB. THE CTLRS AT THE TWR HAVE GONE OUT OF THEIR WAY TO DO THINGS LIKE HOST PROGRAMS TO GET FAMILIAR WITH THE TWR (WHICH I HAVE ATTENDED), AND REALLY TAKE CARE OF THOSE WHO ARE SOLOING FOR THE FIRST TIME, ALONG WITH GETTING CLRNCS FOR THOSE WHO HAVE TO TRAVEL THROUGH THE BUSY LOS ANGELES CORRIDOR. REDUCING THEIR WORKLOAD WOULD KEEP EVERYTHING SAFER FOR EVERYONE.

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.