Air canada 759 July 2017 taxiway

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Pigeon
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Air canada 759 July 2017 taxiway

Post by Pigeon » Sat Jul 15, 2017 9:27 pm

AC759 while landing at SFO lines up on taxiway C instead of runway 28R. Planes awaiting departure notice the error.




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Pigeon
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Re: Air canada 759 July 2017

Post by Pigeon » Sat Jul 15, 2017 9:31 pm




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Re: Air canada 759 July 2017

Post by Pigeon » Sat Jul 15, 2017 10:13 pm


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Re: Air canada 759 July 2017

Post by Pigeon » Sat Jul 15, 2017 10:54 pm

The TSB and FAA reports are subtly different.

The TSB reports that the aircraft had overflown Twy C for around a quarter of a mile at the point when ATC instructed a GA.

The FAA state that the A320 had passed over all four queuing aircraft before being told to GA.

That may or may not amount to the same thing, although if FR24 is to be believed there was about 0.4 miles between the first and last queuing aircraft at the point where the ACA flew over (UAL1 was just about to turn the corner towards the threshold and UAL1118 was just past the November link).

That aside, given that both reports confirm the A320 was already climbing by the time it overflew the third aircraft in the queue, it's clear that the GA was instigated by the pilot before the ATC instruction was given. That's consistent with the ATC recording:

SFO Tower: "Air Canada, go around."

ACA759: "In the go around. Air Canada 759."

Link


No, it isn't. We know (from the TSB report) that the aircraft was already climbing when the controller instructed a GA.


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Re: Air canada 759 July 2017

Post by Pigeon » Sat Jul 15, 2017 11:00 pm

Now Captain Aimer says that AC 759 was 'less than a second from a disaster'. :eek:

The article linked below has a graphic showing UA 1 holding past the Cat I hold line :confused: and says 'the flight came within just 29 feet of one plane'.

Anyway, looks like this incident might not get swept under the rug with the media attention.


"Less than a second from disaster"; New details on near-collision at SFO

By Kris Van Cleave CBS News July 14, 2017, 7:13 PM

WASHINGTON -- It could have been one of the worst aviation disasters in history.

Last Friday night, an Air Canada flight lined up to land on a taxiway in San Francisco where four other airliners were waiting to take off. It pulled up just in time.

On Friday, Canada's Transportation Safety Board said early indications are the flight came within just 29 feet of one plane and "overflew the first two aircraft by 100 feet."

"We're talking less than a second from a disaster," said Ross Aimer, a retired airline captain and CEO of Aero Consulting Experts.

"Less than a second from disaster"; New details on near-collision at SFO - CBS News (http://www.cbsnews.com/news/less-than-a ... on-at-sfo/)
cappt


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Royal
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Re: Air canada 759 July 2017

Post by Royal » Sun Jul 16, 2017 10:43 pm

It will be interesting to see what the investigation turns up.

So far, combination of auto pilot GPS problem and distracted pilot.

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Re: Air canada 759 July 2017

Post by Pigeon » Mon Jul 17, 2017 12:38 am

I think the pilots line up the plane, not ILS.

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Re: Air canada 759 July 2017

Post by Pigeon » Mon Jul 17, 2017 2:03 am

Here's the Transportation Safety Board of Canada's complete preliminary report:

"C-FKCK, an Airbus 320-200 aircraft operated by Air Canada, was conducting flight ACA759 from Toronto/Lester B. Pearson Intl, ON (CYYZ) to San Francisco Intl, CA (KSFO). As the aircraft was on a visual approach to Runway 28R at KSFO, ATC cleared ACA759 to land. Approximately 0.6 nautical mile from the runway threshold, the flight crew asked ATC to confirm the landing clearance for Runway 28R because they were seeing lights. ATC responded in the affirmative, and re-cleared ACA759 to land on Runway 28R. The controller was coordinating with another facility when a flight crew member from another airline taxiing on Taxiway C queried ATC as to where ACA759 was going, then stated that ACA759 appeared to be lined up with Taxiway C which parallels Runway 28R. ACA759 had overflown Taxiway C for approximately 0.25 miles when ATC instructed the aircraft to go around. Four aircraft were positioned on Taxiway C at the time of the event. It is estimated that ACA759 overflew the first two aircraft by 100 feet, the third one by 200 feet and the last one by 300 feet. The closest lateral proximity between ACA759 and one of the four aircraft on Taxiway C was 29 feet. The NTSB is investigating."


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Re: Air canada 759 July 2017

Post by Royal » Mon Jul 17, 2017 6:47 pm

Pigeon wrote:I think the pilots line up the plane, not ILS.
Shows how much I know. ha.

Would the pilot still being using GPS instrumentation that could be off?

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Re: Air canada 759 July 2017

Post by Pigeon » Tue Jul 18, 2017 1:54 am

GPS isn't used to land. An instrument landing system which transmits radio data about alignment is used when available. I don't think it was available at the time and a visual approach (pilot) was used.

An instrument landing system operates as a ground-based instrument approach system that provides precision lateral and vertical guidance to an aircraft approaching and landing on a runway, using a combination of radio signals and, in many cases, high-intensity lighting arrays to enable a safe landing during instrument meteorological conditions (IMC), such as low ceilings or reduced visibility due to fog, rain, or blowing snow.

An instrument approach procedure chart (or 'approach plate') is published for each ILS approach to provide the information needed to fly an ILS approach during instrument flight rules (IFR) operations. A chart includes the radio frequencies used by the ILS components or navaids and the prescribed minimum visibility requirements.

Radio-navigation aids must provide a certain accuracy (set by international standards of CAST/ICAO); to ensure this is the case, flight inspection organizations periodically check critical parameters with properly equipped aircraft to calibrate and certify ILS precision.

An aircraft approaching a runway is guided by the ILS receivers in the aircraft by performing modulation depth comparisons. Many aircraft can route signals into the autopilot to fly the approach automatically. An ILS consists of two independent sub-systems. The localizer provides lateral guidance; the glide slope provides vertical guidance.

A localizer (LOC, or LLZ until ICAO standardisation) is an antenna array normally located beyond the approach end of the runway and generally consists of several pairs of directional antennas.

Glide slope of ILS (G/S)
The pilot controls the aircraft so that the glide slope indicator remains centered on the display to ensure the aircraft is following the glide path of approximately 3° above horizontal (ground level) to remain above obstructions and reach the runway at the proper touchdown point (i.e., it provides vertical guidance).


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