Originally Posted by
Request Orbit
I’ve no clue about any of those things because after about 300 comments we haven’t had anything at all constructive or useful added from that angle, just a load of conjecture that DLH should have done a visual approach - which they could have done apparently! Just not a parallel, paired approach where they’d be responsible for separation.
The second, rebuttal video didn’t offer any of those mitigations you mentioned, just it was busy and that DLH was treated as though it had asked for an opposite end approach - something that would incur a significant delay for everyone - despite the fact it’s request would only mean a single gap created in the same way a go-around would.
The second, rebuttal video doesn't need to mention mitigations like other traffic, other airports using the airspace, noise constraints, etc... it's common sense unless you believe the Controllers are 1) incompetent or 2) in the habit of punishing aircraft for spite or 3) both. Another clue; the Controller told LH to "expect an
extended delay" and, not surprisingly, the info taken from the link in
safetypee's Post 308 confirms what common sense told us:
According to the NAS Airport demand charts, 17:00 and 19:00 are peak times, and on this evening there were over 40 arrivals built into the sequence that would have been impacted in order to accommodate LH458, with further aircraft being held in the adjacent airspace waiting for their inbound slots.
In other words, they were saturated, with streams from the East built and paired-up, other aircraft for SFO holding awaiting their gaps to be created, and LH's extended delay was exactly what the Controller told him to expect. To me, it sure doesn't look like LH was singled-out for a spite-fuelled spanking, It looks more like a bog standard, busy night at SFO with the 3rd busiest TRACON in the US.
Given the congestion, you strangely place little importance on the lateness of LH's notification to ATC of their restriction, which occurred
just 16 miles NW of the airport over BDEGA, and dismiss any impact it would have on their delay. To be clear, LH was originally sequenced for 28R in saturated airspace with no indication of a delay. On the BDEGA Arrival there are multiple, depicted holding patterns yet LH wasn't stuck in one. There was a gap already created for LH on the QB 28R to slide into, yet they couldn't. (that was a wasted gap, man, and someone out there in a hold could've used it).
BDEGA, where they notified ATC, is
just 7 miles/2 minutes before CORKK (9 miles from the airport), where they were to fly a 100 heading that feeds them onto a right downwind for QB 28R. But despite chatting with NORCAL for quite some time no matter which transition they used, and Oakland Center before that, LH advised ATC of their restriction only in response to the CORKK heading clearance, just 2 minutes before the turn.
It's only at that point the Controller knows he's not going vector LH for an ILS to 28R (perhaps that's what you believe he could've done to only "create 1 space"). The QB Visual is named "Quiet" for a reason and, not coincidently, there's an offset compared to, say, the 28R Loc which isn't. With the subsequent "can't maintain visual separation" the Controller also knows that during either ILS 28 there will be no pairing LH with Visual approach aircraft on the other runway because both pilots of a pair need to confirm they can "maintain...". (so there goes another gap someone in a hold could've used). Even if you did push him onto 28R you'd have to break off the existing aircraft LH would've be paired side-by-side with that's flying Tip Toe Visual for 28L. So, off for an 28L ILS LH was sent because the TT visual is predicated on the 28L Loc anyway.
Now overhead SFO, to plug LH in somewhere else takes adjusting both streams from the east, not just the stream for 28L. Both have been built and metered so aircraft wind up side-by-side in pairs on the Visuals. Because LH can't "maintain" and therefore can not have an aircraft paired-up off his right wing, one way or another someone in the already-built stream for 28R has to disappear to create that gap for LH (another one wasted). Then there's the 1 you talked about, the gap LH itself needs in the 28L stream with the proper spacing behind. To preserve the pairs that create the gaps for departures, however, the in-trail spacing must also be applied to 28R aircraft paired to LH's own trailer.
Assuming LH picks up ATIS (broadcast as "Simultaneous Charted Visual Procedures in Use") like everyone else in order to set-up and brief an approach long before, does 16 miles out seem like an overly brilliant time to first advise ATC unable to accept any of the approaches being broadcast on ATIS, because it doesn't seem even a little bit brilliant to me. What approach had LH set-up and briefed?.....No telling, but I suppose an ILS because that's what they required when they finally, belatedly, let the world know.
If LH had advised ATC earlier than 2 minutes before the 28R downwind turn over CORKK....say, way out on the Arrival when they got the ATIS...they would've probably found out they weren't going to get an ILS for 28R, the Controllers could've been cooking up some Plan B spacing required for an ILS 28L, and the gap slated for them on 28R they squandered could've been used by some Visual-accepting aircraft stuck in a hold.
Undoubtedly, some of those holding could accept the Visual and to "Maintain". If they weren't just more victims of a petty, spiteful and/or incompetent ATC, perhaps they were being held because a few others before LH showed up, also waited until 16 miles out to inform they needed ILSs, which jammed up the works so completely simple "1 gap" solutions just weren't possible.. Whatever the reason, it's 100% certain they had a limit on their endurance, so LH certainly would't be special in that respect.