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0 pointsmannykannot4y ago0 comments

> I understand that they were in different frequencies with different controllers.

If that is so, then it seems from the recording that the Metroliner pilot was only informed about the Cessna ahead of him and on approach to 17R, not of the Cirrus.

The Cirrus pilot is told about the Metroliner in an exchange that goes thus:

TWR: "Cirrus 6DJ, traffic you're following just turned right base there ahead and to your right at 6600', Cessna."

6DJ: "I have traffic in sight, 6DJ."

TWR: "Cirrus 6DJ, follow them, runway 17R, cleared to land. Additional traffic north shore, it's a Metroliner for the parallel runway."

6DJ: "Traffic in sight, cleared to land 17R, 6DJ."

Now, does that second "traffic in sight" refer to both aircraft, or only to the Cessna he had just been cleared to follow? It would be unambiguous if he had replied "two in sight", but if, for whatever reason, the mention of the Metroliner (in the same call as the clearance was given) had not registered, the Cirrus pilot would not have been aware that more than one other aircraft needed his attention. And if the Metroliner communication was being conducted on a different frequency, neither pilot would have had any other opportunity to become aware of the other airplane, except by seeing it - and, in addition to the Metroliner pilot presumably being in the left seat, the Cirrus was banked right, turning final, and one might guess its pilot was probably looking at the runways and/or the Cessna ahead.

Putting this together, I suspect the Cirrus pilot never registered the presence of the Metroliner until the collision - and I doubt the Metroliner pilot saw the Cirrus even after the collision, given that he thought he had an engine failure (he might have seen it earlier, when it was heading north on downwind, and assumed it was behind him.)

This does not alter the fact that the Cirrus pilot overshot the 17R approach while turning onto final, and it is this which caused the collision. One other fact, pointed out by several commentators: the Cirrus was travelling at about 160 kts at the time, so any delay in turning final results in being out of position more quickly than in your average small, single-engined airplane.

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sokoloff4y ago

160 kts (around 140 indicated) does not seem like a remotely appropriate airspeed to join a pattern full of Cessnas in closed traffic.

SR22 Vs0 is 59 knots (call it 60 to make the math easier). 1.3 x Vs0 is a reasonable "over the fence" speed, so 78 knots (call it 80) indicated would be good on short final, maybe 90 on base-to-final. (Instead, they were descending and thus accelerating slightly and hit 169 knots on the base leg.)

Bombing into the pattern over 50 knots faster than appropriate (70 knots faster than the traffic you're following and 40 knots faster than the much larger and on-profile Metro on the parallel) might be contributing, but certainly suggests to me that the Cirrus crew was behind the airplane.

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omegant4y ago

“ Putting this together, I suspect the Cirrus pilot never registered the presence of the Metroliner until the collision - and I doubt the Metroliner pilot saw the Cirrus even after the collision, given that he thought he had an engine failure”

This is what I think aswell. The overshoot may be either way a miss identification of the runway, or just a poorly executed turn to final of the 17R. The investigation is going to be interesting.

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