Comment by daviding | Hacker News Reader

Comment by daviding | Hacker News Reader

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I think the plan was for the Southwest to be given take off clearance quickly before the private jet arrived, but the controller got distracted by a route amendment for another flight that came in and they got their priorities wrong. In the US it's not uncommon for a 'Cleared to Land' to be given while something is then lining up and waiting for immediate Take Off clearance.

In the EU / Canada this isn't allowed (landing clearance is only given if the runway is completely clear), but then the US pushes a lot more aircraft through its busy airspace this way. San Diego is a busy airport with just a single runway (due to the geography) near a couple of military bases and has a steep approach over the city - if there had been some ground fog like there often is at KSAN then this could have ended very differently.

Also, you can see in the video that due to the steep approach, the SWA was at the beginning of the runway, but the jet on approach would have landed further down, as the landing is offset there. This still would have be been dangerous but not a definite case of collision.

Yea. The incoming jet was on a 5-mile final. Being a small jet it's "slow" so that 5-mile final is 3-5 minutes. You can see 19:04Z when the Southwest jet get's the "line up and wait". 19:07Z is the missed approach. If ATC has given them the departure clearance relatively quickly, there would have been no issue as Southwest would have hit the gas and been long gone... but ATC didn't.

This is not uncommon for aircraft to get on the runway and take off while another aircraft is on final. If you want a good video of how this more typically works (and sometimes doesn't work), here's one from an incident at SFO about 2 months ago: https://www.youtube.com/watch?v=DrRGde5J8mo

And another from SFO: https://www.youtube.com/watch?v=E4cewwhcL5c

In both the SFO cases, they got the "go around" from ATC much earlier and no one got too close to each other. Keeping in mind that SFO is extremely busy and lands two parallel runways at the same time: https://www.youtube.com/watch?v=YsKhZm78DuY

then the US pushes a lot more aircraft through its busy airspace this way

This may be true overall, but San Diego is barely top-25 in the US in passenger traffic.

And Heathrow is busier (even measuring per runway, since it has 2). And both Gatwick and Mumbai handle more flights on a single runway.

They don't land planes at KSAN in the fog, because of the steep decent. So it would have ended very differently, because that Citation would have been diverted elsewhere.

Real error here was that SWA should have been told to hold short and then expedite as the SWA boys like to do after Citation was clear or to expedite from the getgo. Both would have worked just fine.

Also worth mentioning that while you can give landing clearance onto a runway that is not clear at the time, you still cannot have multiple aircraft on a given runway simultaneously, and there are very strict minimum separation requirements that vary depending on the airport which for KSAN is 5NM

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