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NTSB Issues Investigative Update on San Francisco Airport Near Miss

ntsb.gov

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

#21

Post by Stratoscope »

johnm1019 wrote: post #14
Animats wrote: post #4

This was a very close call. Initial reports indicated it was like an ordinary go-around. No. "The incident pilots advanced the thrust levers when the airplane was about 85 feet above ground level. Flight data recorder data indicate the airplane was over the taxiway at this time. About 2.5 seconds after advancing the thrust levers, the minimum altitude recorded on the FDR was 59 feet above ground level." They overflew…

Something doesn't add up then, the listed elevation for SFO is 13.1 ft MSL. http://www.airnav.com/airport/KSFO UPDATE: tolerances around GL are 20 ft https://www.ecfr.gov/cgi-bin/retrieveECFR?gp=&SID=&r=PART&n=...

"...the minimum altitude recorded on the FDR was 59 feet above ground level." [emphasis added]

AGL (elevation above ground level), not MSL (elevation above mean sea level). The runway/taxiway elevation is already taken into account. They were 59 feet above the taxiway.

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

#22

Post by greenhouse_gas »

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.

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

#23

Post by notatoad »

modeless wrote: post #3

Before I couldn't imagine how anyone could make this mistake, but now I see it. The pilots were familiar with SFO and knew that there were two runways, but didn't realize the left hand runway lights were turned off, so they had an off-by-one error when choosing the runway.

i'm not a pilot and have no idea what it looks like when landing a plane at night, so i really shouldn't be commenting here, but: the report says the one operational runway had 2400 ft of approach lighting that was functional. The disabled runway had no approach lighting, and presumably the taxiway didn't have any approach lighting because nobody should be approaching a taxiway. So yes, they were just "off by one", but they were off by one on a dataset of one.

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

#24

Post by phire »

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.

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

#25

Post by planetjones »

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 enough of the 'process' to capture evidence kicked in soon enough. Judging by the photo and distances this looks like it was an imminent disaster, which hadn't been clear to me previously.

Source: https://www.theguardian.com/business/2017/aug/03/air-canada-...

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

#26

Post by abritinthebay »

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

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

#27

Post by isomorphic »

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 before midnight after a flight from Toronto, it was so far off course that it did not appear on a radar system used to prevent runway collisions.

The next paragraph states they are working on improving that.

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

#28

Post by matt_wulfeck »

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?

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

#29

Post by mosheroperandi »

bgentry wrote: post #11

I would love to see the video that frame is taken from to watch the arc of the plane as it initiated go-around and missed a collision by just a few feet.

From the current report (https://ntsb.gov/investigations/Pages/DCA17IA148.aspx):

The NTSB has obtained a security camera video from SFO of the incident approach that will be released along with the other factual information when the public docket for this incident is opened in the next several months.

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