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."<p>They overflew an Airbus A340 on the taxiway, tail height 55 feet.
<i>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><p>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.<p>Source: <a href="https://www.theguardian.com/business/2017/aug/03/air-canada-near-miss-picture-shows-how-close-planes-came-to-crashing" rel="nofollow">https://www.theguardian.com/business/2017/aug/03/air-canada-...</a>
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.
Previous discussion on this topic: <a href="https://news.ycombinator.com/item?id=14741605" rel="nofollow">https://news.ycombinator.com/item?id=14741605</a><p>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.
So the guy keying up and saying "Where is this guy going?" and "He's on the taxiway" might actually have made a difference in the outcome, huh:<p>> The flight crew of the first airplane in queue on taxiway C (UAL1) transmitted statements regarding ACA759, one of which mentioned the alignment of ACA759 with the taxiway while ACA759 was on short final (see figures 2 and 3).<p>> The flight crew of the second airplane in queue on taxiway C switched on their airplane’s landing lights as the incident airplane approached.
I'm think I'm getting it now. Look here at the map:<p><a href="https://www.google.com/maps/@37.6265932,-122.3812022,15z?hl=en" rel="nofollow">https://www.google.com/maps/@37.6265932,-122.3812022,15z?hl=...</a><p>28L is longer than 28R. Similar to how 28R (or at least its lighting) is longer than taxiway C. The general geometric appearance of the lighting was probably similar enough to what they were used to that it looked mostly correct. As for the X, it was 20 feet wide and about 1000 feet away from where they were aiming, so it would not be relevant to the incident.
VASAviation made a video on this with radio traffic from the incident.<p><a href="https://www.youtube.com/watch?v=ZW-ETmZU0u8" rel="nofollow">https://www.youtube.com/watch?v=ZW-ETmZU0u8</a> (1:33)
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)<p>With the wheels down, they would just tear through the hull of the lower plane, right?
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.
What I don't understand (and I'm being honest here) is that between GPSs, computers, and HUDs, how do these errors still happen?<p>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.
The map view seems a bit off to me, UAL1 obviously saw the incoming plane and on the photos it looks to me like there are 4 planes in a straight line, yet UAL1 is oriented in the other direction on the radar.
Wouldn't this whole problem disappear if runways were designed differently, at the minimum one exclusive for landing and one for takeoff with no chance for planes landing and planes taking off to meet, like 2 parallel hockey sticks.<p>Both runways would be painted and lit up completely differently with large lettering explicitly saying take off and landing.