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NTSB Issues Investigative Update on San Francisco Airport Near Miss

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Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#41

Post by reustle »

planetjones wrote: post #25

Investigators could not hear what the Air Canada captain and co-pilot said to each other during the aborted landing because their conversation was recorded over when the plane made other flights, starting with a San Francisco-to-Montreal trip the next morning. Recorders are required to capture only the last two hours of a plane’s flying time I wonder what the procedure is in a near Miss like this. It looks like not e…

On top of that, storage is cheap. They can probably afford to keep conversations longer than 24 hrs.

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#42

Post by TrickyRick »

phire wrote: post #24
Flammy wrote: post #2

Previous discussion on this topic: https://news.ycombinator.com/item?id=14741605 This literally could have been one of the worst accidents in American aviation history had the pilots of the landing airplane failed to react in time. There were 4 fully loaded and fueled passenger jets directly ahead of them.

And they cut it extremely fine. The final NTSB report will probably calculate this, but I'm guessing if they had waited another second or two before shoving those throttles forwards they would have hit a plane (or three). Whats even more scary, is I get the impression that the pilots only shoved the throttles forwards because the tower told them to abort.

Does the NTSB do what-ifs? Seems odd for an investigative body to do guesswork on what type of disasters could have occurred.

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#43

Post by mseebach »

isomorphic wrote: post #27
greenhouse_gas wrote: post #22

What I don't understand (and I'm being honest here) is that between GPSs, computers, and HUDs, how do these errors still happen? I mean that if your GPS sees you're aiming at the wrong runway, why can't it alert the pilot (and/or tower) that it's going to miss.

I don't think GPS is accurate enough for that sort of thing, you'd need ground radar, working with onboard computers that understand which runway you're cleared for, etc. (I'm not a pilot, I'm speculating.) If you read the Guardian article from planetjones' comment: https://www.theguardian.com/business/2017/aug/03/air-canada-... Quoting: The investigators said that as the Air Canada jet approached the taxiway just be…

It's called ILS, Instrument Landing System, and it's been around for literally 80 years.

> The first landing of a scheduled U.S. passenger airliner using ILS was on January 26, 1938, when a Pennsylvania Central Airlines Boeing 247D flew from Washington, D.C., to Pittsburgh, Pennsylvania, and landed in a snowstorm using only the Instrument Landing System

https://en.wikipedia.org/wiki/Instrument_landing_system

Presumably they must have done a visual approach or something, because their ILS would have been outright incapable of directing them down the taxiway, as it's for obvious reasons not equipped for ILS approaches.

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#44

Post by TrickyRick »

reustle wrote: post #41
planetjones wrote: post #25

Investigators could not hear what the Air Canada captain and co-pilot said to each other during the aborted landing because their conversation was recorded over when the plane made other flights, starting with a San Francisco-to-Montreal trip the next morning. Recorders are required to capture only the last two hours of a plane’s flying time I wonder what the procedure is in a near Miss like this. It looks like not e…

On top of that, storage is cheap. They can probably afford to keep conversations longer than 24 hrs.

Storage is cheap today, it wasn't 30 years ago when these rules were put in place (And probably some of the systems manufactured)

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#45

Post by stordoff »

matt_wulfeck wrote: post #28
greenhouse_gas wrote: post #22

What I don't understand (and I'm being honest here) is that between GPSs, computers, and HUDs, how do these errors still happen? I mean that if your GPS sees you're aiming at the wrong runway, why can't it alert the pilot (and/or tower) that it's going to miss.

I'm wondering the same thing. Why don't planes land themselves at this point?

Raises an interesting question of which is safer: ILS automated landing with pilots on standby to take over, or pilots manually landing guided by ILS.

On one hand, a fully automated landing leaves less room for human error (you can still instruct the plane to land in the wrong place), but you're more reliant on things working as they should. If the automated systems fail for any reason, you've got pilots who are less practised at landings needing to take over at a moment's notice

I also suspect that a pilot making a active landing would react quicker to things than shouldn't happen (and thus may not be picked up by an automated system), such as a ground plane being in the wrong place, or some sort of mechanical failure.

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#46

Post by TrickyRick »

abritinthebay wrote: post #26
viraptor wrote: post #20

I've seen people mentioning this could be a big disaster, but I'm curious exactly what the effects could be. Specifically, ignoring the wheels for the moment, would the hull of the landing plane slide off on contact at all, or would the planes just get squashed? I have no intuition about friction / stiffness of materials at that scale. (I'm also assuming the planes were at least a little bit offset to the side) With…

It wouldn’t have been just the wheels. They’d have flattened onto each other in a big squash that blew fuel everywhere. It would have probably continued due to momentum as a fireball towards the 3 other fully loaded planes. Basically it could have been a 5 fully loaded plane bowling alley of flaming metal at 150mph

Actually the first plane on the ground was staggered with respect to the others and the final two ones had quite a bit of separation so another, not too unlikely outcome, is that it would have hit UAL1 and then veered of the taxiway, wrecking the ACA flight but nothing else (Save for possible some last-row passengers on UAL1).

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#47

Post by mseebach »

TrickyRick wrote: post #42
phire wrote: post #24

Earlier quoted context omitted.

And they cut it extremely fine. The final NTSB report will probably calculate this, but I'm guessing if they had waited another second or two before shoving those throttles forwards they would have hit a plane (or three). Whats even more scary, is I get the impression that the pilots only shoved the throttles forwards because the tower told them to abort.

Does the NTSB do what-ifs? Seems odd for an investigative body to do guesswork on what type of disasters could have occurred.

Agreed. It's fairly uninteresting (from an accident-prevention perspective, not a news-selling one) to muse about cutting it close, as soon as you get into seconds-territory, you're way too close. The fuck-up was lining up for the wrong approach in the first place, landing on the taxi-way is insanely dangerous, even if it's empty.

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#48

Post by jbg_ »

matt_wulfeck wrote: post #28
greenhouse_gas wrote: post #22

What I don't understand (and I'm being honest here) is that between GPSs, computers, and HUDs, how do these errors still happen? I mean that if your GPS sees you're aiming at the wrong runway, why can't it alert the pilot (and/or tower) that it's going to miss.

I'm wondering the same thing. Why don't planes land themselves at this point?

The A320 can land itself, but pilots regularly approach and land manually to keep their manual flying skills current (as the automated systems -- both the ground components and aircraft components as well as the communications channels between them -- can fail).

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#49

Post by mosheroperandi »

drfuchs wrote: post #33
phire wrote: post #24

Earlier quoted context omitted.

And they cut it extremely fine. The final NTSB report will probably calculate this, but I'm guessing if they had waited another second or two before shoving those throttles forwards they would have hit a plane (or three). Whats even more scary, is I get the impression that the pilots only shoved the throttles forwards because the tower told them to abort.

No, they started pulling up just before hearing from the tower; click on the link at the bottom of the referenced page: "The full investigative update and other information about the incident are available online at: https://go.usa.gov/xRPFk​ " for more detail, including: o At 2356:04 PDT, ACA759 reappeared on the local controller’s ASDE-X/ASSC display as it passed over the first airplane positioned on taxiway C. o A…

Yeah, the 3 video frames in that report are matched to transmissions the timestamps. Unless the angle is deceiving, you can sorta visually extrapolate from the descent of the first two at :01 and :04, that 6 seconds later, when the go-around was give at :10, they would have been on the ground had they not pulled up.

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#50

Post by justinjlynn »

TrickyRick wrote: post #44
reustle wrote: post #41

Earlier quoted context omitted.

On top of that, storage is cheap. They can probably afford to keep conversations longer than 24 hrs.

Storage is cheap today, it wasn't 30 years ago when these rules were put in place (And probably some of the systems manufactured)

Retrofits to safety equipment are common when new issues are discovered. That said, an enforcement action or a procedure change is probably necessary in this case.
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