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Abstract of the NTSB Report on Air Canada flight 759's taxiway overflight at SFO [pdf]

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Re: Abstract of the NTSB Report on Air Canada flight 759's taxiway overflight at SFO [pdf]

#11

Post by wmblaettler »

oasisbob wrote: post #10
cmurf wrote: post #5

I'm not operationally familiar with SFO. But based on experience at other airports, a taxiway at night can be a sea of black at even 100' above the ground. I would probably see airplane navigation lights at some point, but would I bet my life on it? No. So this incident has to be taken seriously. However, I'm still not clear from this reporting how the crew mistook blue taxiway lighting for white runway lighting. Thi…

I don't understand it either. Here in Seattle, SeaTac airport has a parallel taxiway (Taxiway Tango) with a long history of being mistaken for a runway. The list of things tried so far to resolve the issue is interesting: https://www.bizjournals.com/seattle/news/2015/12/31/tango-ta...

The very first thing I thought of upon reading your comment "The list of things tried so far to resolve the issue..." was "What about a big lighted 'x'?" then I clicked the link.

Re: Abstract of the NTSB Report on Air Canada flight 759's taxiway overflight at SFO [pdf]

#12

Post by aeternus »

I'm surprised that remote video cameras aren't used by tower controllers.

The perspective of the control tower makes it difficult to catch issues like this, but a simple video camera aligned with the center-line of each runway would allow controllers to more easily verify that planes are lined up as well as other possible issues like gear down & locked, etc.

Re: Abstract of the NTSB Report on Air Canada flight 759's taxiway overflight at SFO [pdf]

#14

Post by throwaway5250 »

cmurf wrote: post #5

I'm not operationally familiar with SFO. But based on experience at other airports, a taxiway at night can be a sea of black at even 100' above the ground. I would probably see airplane navigation lights at some point, but would I bet my life on it? No. So this incident has to be taken seriously. However, I'm still not clear from this reporting how the crew mistook blue taxiway lighting for white runway lighting. Thi…

I give up--why shouldn't airplane strobes be on while they're on the ground?

Re: Abstract of the NTSB Report on Air Canada flight 759's taxiway overflight at SFO [pdf]

#15

Post by tialaramex »

CVR overwrite is bad news here. The crew knew this was a serious problem when it happened, there's no way they should have allowed the CVR, crucial evidence of exactly what happened, to be overwritten.

Perhaps the full report will have more detail on this, as it stands I have to believe somebody made the decision to overwrite this because they thought it'd be better if it didn't exist. Whether that's the crew, their bosses or other staff, somebody managed to go from "serious incident, preserve evidence" to "maximum ass covering" and that person or persons are an obstacle to effective investigation and thus to safe air travel.

Re: Abstract of the NTSB Report on Air Canada flight 759's taxiway overflight at SFO [pdf]

#16

Post by 8_hours_ago »

SaberTail wrote: post #13

If anyone would like to listen to the ATC radio: https://www.youtube.com/watch?v=ZW-ETmZU0u8

I was just about to post that link! VASAviation has a really good youtube channel with ATC radio recordings and high quality visualizations of all kinds of interesting events: https://www.youtube.com/user/victor981994

Re: Abstract of the NTSB Report on Air Canada flight 759's taxiway overflight at SFO [pdf]

#17

Post by tetrep »

> Cockpit voice recorder (CVR) information was not available for this incident because the data were overwritten before senior Air Canada officials became aware of the severity of this incident.

How long are recordings normally kept? I would assume at least a few days for mundane flights (storage is cheap, isn't it?) but any sort of incident similar to this I would assume they keep recordings for much longer, if only for internal purposes.

Re: Abstract of the NTSB Report on Air Canada flight 759's taxiway overflight at SFO [pdf]

#18

Post by walrus01 »

tialaramex wrote: post #15

CVR overwrite is bad news here. The crew knew this was a serious problem when it happened, there's no way they should have allowed the CVR, crucial evidence of exactly what happened, to be overwritten. Perhaps the full report will have more detail on this, as it stands I have to believe somebody made the decision to overwrite this because they thought it'd be better if it didn't exist. Whether that's the crew, their…

If I understand CVR tech correctly, it's running and constantly overwriting the storage in a loop whenever the plane is powered up. A lot of airplanes are 10, 15, 20 years old. CVR are based on some pretty old late 1980s technology, it's not like a modern flash based storage system with effectively infinite capacity for stereo 44KHz audio (64, 128GB, etc). There's maybe 1 or 2 hours of recording time, max.

Re: Abstract of the NTSB Report on Air Canada flight 759's taxiway overflight at SFO [pdf]

#19

Post by metanoia »

gok wrote: post #4

It's kind of baffling to me that there's a system for detecting collisions with other airplanes in the sky (TCAS) and a system for detecting collisions with the ground (EGPWS) but not system for detecting collisions with other airplanes on the ground. This easily could have killed a thousand people.

SFO has ground radar systems (ASDE-X/ASSC) [1] which allows ground and tower controllers to see potential conflicts on taxiways and runways. Pure speculation, but I don't think that these systems' conflict logic take into account an aircraft trying to land on a taxiway.

[1] https://en.wikipedia.org/wiki/Airport_Surface_Surveillance_C...

Re: Abstract of the NTSB Report on Air Canada flight 759's taxiway overflight at SFO [pdf]

#20

Post by jonah »

wmblaettler wrote: post #11
oasisbob wrote: post #10

Earlier quoted context omitted.

I don't understand it either. Here in Seattle, SeaTac airport has a parallel taxiway (Taxiway Tango) with a long history of being mistaken for a runway. The list of things tried so far to resolve the issue is interesting: https://www.bizjournals.com/seattle/news/2015/12/31/tango-ta...

The very first thing I thought of upon reading your comment "The list of things tried so far to resolve the issue..." was "What about a big lighted 'x'?" then I clicked the link.

I'd like to know why they removed it.
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