Originally Posted by
bud leon
In my opinion the problem here largely lies with the controller not providing more information on where he was trying to position Cathay in the first place, and then continuing with the instruction when it was clear there was a risk of loss of separation.
That is, when he gave the first turn instruction he should have advised CPA 892 that the turn should be immediate to get in front of UAL 1515, and once that didn't happen, he should have lined CPA 892 behind UAL 1515. The direction to turn was quite late given the position of the aircraft in any case. I think it's very odd that he didn't change the sequence when it was clear the initial instructions were not followed and so could cause loss of separation. it seems reasonably clear that the controller was fixated on managing congestion, which he probably does his entire shift. I would say that is the root cause. Both pilots express a surrendering of control to ATC.
The controller was perfectly clear and they weren't being sequenced for the same runway. Cathay was being vectored and was cleared to intercept the localizer for 28L. On the other hand, UAL 1515 (the traffic pointed out by the controller which Cathay acknowledged they had visually and instructed to maintain visual separation from, also acknowledged) was on approach for 28R. In the recording the Left and Right runway distinctions are made and Cathay was advised after visual contact that UAL 1515 was going to the Right; they didn't have to infer, deduce, or suppose it. If you listened to the recording I'm surprised you missed it.
Cathay would have known before this recording began that they were being vectored/positioned for 28L, something that's clear in the instructions from ATC that we do hear in the video and is always stated by the Approach controller to the crew when initiating vectors off the published arrival, something that occurred before the recording began. The Cathay crew would also know there were parallel runway ops to 28R in progress. ATIS states it and 2 the daisy-chains of aircraft on TCAS makes it obvious.
28L and 28R are only 750' apart at SFO, but with a final vector of 310 to intercept the 28L localizer inbound course of 284, that's only a 26 degree intercept angle. Hardly something difficult for automatics or by hand, it's downright mild, and raises the question of correct freq tuned or automation that went unarmed.
The problem wasn't an ATC controller fixating on his original sequencing plan, it was Cathay crew fixating on something else besides intercepting the correct localizer as instructed/cleared/acknowledged and maintaining the lateral visual separation of UAL 1515 on approach for the parallel runway they said they would maintain.
Contrary to the cause being both pilots surrendering control to ATC, how about a crew not following clear ATC instructions/clearances they've acknowledged, read back, and accepted?