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-   -   Near miss with 5 airliners waiting for T/O on taxiway "C" in SFO! (https://www.pprune.org/rumours-news/596900-near-miss-5-airliners-waiting-t-o-taxiway-c-sfo.html)

underfire 15th Jul 2017 10:51


Do we know whether the NTSB is even looking at this SFO incident?
A pooched AR procedure by a foreign carrier, one would certianly hope so! Especially the AR part.

This 'near miss', 'almost the worst airline crash in history' kindof stories all over the press.


It looks like the heights being quoted have a ±50' resolution,
With the quoted 100' clearance, with accuracy/latency, wheels and tail down a bit..damn

Video from Youtube, not very good, but one can see the runway lights vs taxiway (green lights) pretty clearly at 3:44 This is on Quiet Bridge Visual.
https://youtu.be/O3LTYeZrzH8
http://i63.tinypic.com/1zldmwx.jpg

another night landing
http://i64.tinypic.com/1zc1kdu.jpg

Ian W 15th Jul 2017 11:15


Originally Posted by Kal Niranjan (Post 9831022)
Wow you are all so knowledgeable and so very kind.

Had this incident happened to a non western carrier, the amount of scorn and racial insinuations would have been thunderously deafening! ' nuff said.

Thanks Kal, not being kind - being realistic. Pilots should all learn from this incident because the same WILL happen to them at some time. Unfortunately, as you will have seen many of the posts on this thread have started with: cannot believe that it is possible for professional pilots etc etc

It is absolutely nothing to do with professionalism or capability it is all to do with cognition and perception - human factors experiments Repeatedly show the brain has limits and cannot work in some ways.

Try to read this post and recite a nursery rhyme and listen to what someone is saying and read it back you cannot. Your brain has only one verbal 'cognitive channel'. A huge amount of research has been carried out in visual perception yet that is all forgotten when airports are designed. Everyone gets a degree of cognitive tunneling (focusing on a problem) when doing something challenging and that is when mis-perception can occur. This has been repeatedly demonstrated in research and happens continually in real life.

_Phoenix 15th Jul 2017 11:21

Underfire, see the video in post here
I didn't see the curtain changing color (first time, while counting the passes). Second time I was amazed that I missed the curtain as big as the screen size. I'm sure that AC 759 pilots were amazed too during the second approach.

Ian W 15th Jul 2017 11:32

OK now put a line of widebodies onto that taxiway and you will have a set of wingtip lights that are all around 100ft either side of the center line at close to 300ft apart along the 'taxiway'. Not unlike runway lights on a 200ft wide runway at 300ft intervals......

That is enough to trigger the 'illusion' of it being a runway - then the anti-collision lights on the aircraft would look like someone on the 'runway'.

You are not comparing like with like.

DIBO 15th Jul 2017 11:54


It looks like the heights being quoted have a ±50' resolution
Raw mode S data (available to NTSB) should have a resolution of 25ft


one can see the runway lights vs taxiway (green lights) pretty clearly at 3:44
I'm pretty sure that being perfectly aligned with twy C, might result in a substantial difference in brightness of the green centerline.


...will have a set of wingtip lights ... ... Not unlike runway lights
a couple of reds & greens <-> rwy lights? Nah, don't think so.

Loose rivets 15th Jul 2017 12:16

This is what I've been trying to get across.


PM is not being coached by PF into seeing the same thing. Therefore I'd expect PM to chirp up quite early on and challenge PF about where they were landing.
But apart from that hesitation in his voice when ATC told him they had the runway - he too seemed locked on to a false reality.


It is absolutely nothing to do with professionalism or capability it is all to do with cognition and perception - human factors experiments Repeatedly show the brain has limits and cannot work in some ways.
IMHO Those rows of aircraft lights fooled them both. Tiredness factor to add perhaps, but despite the magnitude of the incident, my heart goes out to those two guys.

Bergerie1 15th Jul 2017 12:34

Having studied workload, stress and visual illusions in aviation, I believe Ian W's posts are along the right lines. Under some conditions, human perception can be very fragile. Even the best professionals can be fooled.

BluSdUp 15th Jul 2017 12:58

Professional pilots tune the ILS and xcheck.
At 500`on loc on gs 2 white 2 read stabelized . PNF : "500 feet continue"
It is simple.
Positive identification, always! If not GA, try again.

Airbubba 15th Jul 2017 13:48


Originally Posted by portmanteau (Post 9831374)
National Transportation Safety Board Aviation Incident Preliminary Report

I did not know this existed, thanks for finding this portmanteau. :ok:

Whether AC 759 initiated the go around before or after the ATC call, 100 feet AGL is way too low to figure out they were over the taxiway. :=

If the CVR wasn't impounded in time, maybe the FDR was. It should have radar altitude data to correlate the descent and go around profiles over the taxiway.


Originally Posted by cactusbusdrvr (Post 9829753)
I have done many FMS Bridge visuals in the A320 family. You do not have the ILS raw data because it is an FMS approach. You have VASI and the electronic glidepath. You can hard tune the lLS through the RMP but no one ever does.

There seems to be a consensus that most A320 crews wouldn't tune the ILS for this RNAV approach and even if you did, the data would not be displayed unless you switched approach modes.

I'm guessing that the AC A320 may have had old style radio nav without GPS, does this sound right? You often get map shifts from what I've seen, especially down low in places with higher surrounding terrain like SFO and KIX.

ironbutt57 15th Jul 2017 13:54

Professional pilots tune the ILS and xcheck.
At 500`on loc on gs 2 white 2 read stabelized . PNF : "500 feet continue"
It is simple.
Positive identification, always! If not GA, try again.


are you familiar with an FMS approach?? it is also flown multiple times daily by many professional pilots

aterpster 15th Jul 2017 14:15


Originally Posted by ironbutt57 (Post 9831667)

are you familiar with an FMS approach?? it is also flown multiple times daily by many professional pilots

I flew only one airplane with an FMS, the 767 in its early days. We didn't have an FMS approach procedure at the time. We were required to bring up the ILS on a visual, no different than with the old round-dial airplanes.

In general terms how is an FMS approach set up?

ironbutt57 15th Jul 2017 14:29

an FMS approach is based on information in it's own database, some provide lateral and vertical guidance, others only lateral...the 767 was different as the ILS could be tuned independently with the tuner on the centre pedestal as I remember, since this particular approach is offset, manually tuning the ILS was probably not a part of their SOPs, it is possible in the Airbus, but generally only used during downgrading of the FMGS system...the FMS approach is displayed as an LNAV track on the nav display..

BluSdUp 15th Jul 2017 14:39

Iron butt
If you bother to read the thread , you would see I already covered this.
As for your condescending tone, please!
There is few types of approaches invented I have not flown.

As for the specific selection on THIS AC A320 , I would be interested to know what AC mandate for a visual night approach.
I can not recall how any Lnav/vnav approaches are specifically entered and executed, as it is 13 years since I was qualified on A320.

But , any FMS based approach active, it will give you a strong full fly left FD at this point.

Another thing: Who has mapshift these days?

I say again: Visual Night , tune and follow approach aid for runway landing. AP on.

ironbutt57 15th Jul 2017 14:52

Aterpster asked, I answered, simple...take it as condescending, thats up to you..havent seen any pic of the MCDU of that approach..I can get one...it could well be the database ends prior to the runway...following the ILS for that runway may well put you outside the lateral path for the assigned approach, most likely they would have flown the assigned and published approach which is the "Quiet Bridge" fms approach...slightly offset over the bay for noise abatement procedures..in later stages of the approach it joins the ILS track, but not sure if that late portion is coded into the database, or it's flown "out the window" from that point, so being professional pilots, they did indeed fly their assigned, published approach...

RAT 5 15th Jul 2017 14:53

I've only flown various Boeings, the latest being B738NG. LNAV/VNAV & RNAV approaches were authorised, BUT any ground based aids that helped confirm the FMS guided approach had to be tuned and monitored as back-up. Why would Airbus not tune and monitor a back-up aid, whether it be manually tuned or automatic? Is not a common standard in aviation to have back-up systems for most critical areas. If there are 2 fuel pumps, 2 hydraulic pumps, 2 braking systems, 2 gear & flap systems, 2 pilots......then why not have 2 independent NAV systems in use if they are available? Why rely on only 1 to bring you in close proximity with a concrete grave?

Shore Guy 15th Jul 2017 15:29

Honeywell "Smart Runway" ....

from this document: https://aerospace.honeywell.com/en/~...escription.pdf




4.3.8 Taxiway Landing
The purpose of the Taxiway Landing caution is to provide crew awareness that the aircraft is not lined up with a runway at low altitudes.
4.3.8.1 Annunciation Criteria
The caution is generated if:
Aircraft is airborne between 150 and 250 feet AGL (Radio Altitude), and Aircraft climb rate is less than 450 FPM, and
Aircraft is within 5 NM of a runway and is not lined-up with a runway.
NOTE: RAAS functions are based on a database of runway locations. The system does not have knowledge of the location of taxiways.
4.3.8.2 Message Content
The aural message string “Caution Taxiway, Caution Taxiway” is annunciated once each time the caution is generated. Refer to Figure 4-13.
4.3.8.3 Audio Level
The aural message is generated at the EGPWS Cautions and Warnings volume level.

Lonewolf_50 15th Jul 2017 17:04

SFO, two different incidents:
1) crew approaching a runway, something doesn't look right, they go along and are 30+ knots slow on final, crash, 3 dead, many injured, Asiana. GA decision too late.

2) Crew approaching runway, something looks wrong, someone speaks up, someone calls tower, and a GA decision is made in a timely fashion. Air Canada.

Cockpit culture and willingness to say "this doesn't look right" and speak up (confess to confusion) is to me a crucial difference, and why there is egg on face, and no dead bodies.

Granted, one would hope that all of the details and airmanship issues discussed for the last few hundred posts would prevent it getting that close.
I am glad someone spoke up and said "this doesn't look right" and then the GA happened in a timely fashion.(well, maybe not timely, given how close this was).
No approach is too beautiful to wave off.

gwillie 15th Jul 2017 18:04

This story was referenced on a Canadian (air cadet caliber) forum.......an interesting read (not previously mentioned here, afaik).........and, it features a not-unfamiliar actor !

Pilots mistake taxiway for runway at Sea-Tac | The Seattle Times

From.....2005 !

RAT 5 15th Jul 2017 18:22

manually tuning the ILS was probably not a part of their SOPs, it is possible in the Airbus, but generally only used during downgrading of the FMGS system...the FMS approach is displayed as an LNAV track on the nav display..

I'm still waiting for an answer from the Airbus gurus: You've answered the lateral aspect of an FMS approach, if indeed they were doing one inside 4nm, but what were they using (what do you expect) for vertical guidance?

Airbubba 15th Jul 2017 18:29


Originally Posted by BluSdUp (Post 9831712)
Another thing: Who has mapshift these days?

From a discussion on another thread about the Air Canada Halifax crash:


Originally Posted by peekay4 (Post 8948955)
In reality, a large number of A320s (and even A330s/A340s) do not have even vanilla GPS installed as part of the navigation system! No GPS units. No MMR. These A320s depend solely on radio updating (VOR/DME) or manual IRU alignment before takeoff.

(I believe the Air Canada aircraft involved in this accident [YHZ - Airbubba] was not equipped with GPS.)

Also, some of these aircraft have dual FMS which are not GPS compatible. Total upgrade price == very costly.

I'm wondering if the AC A320 at SFO was in this legacy no-GPS configuration.

Still, even if the setup is FMS with no raw data displayed, at the end of the day this is supposed to be a visual approach. Does AC turn off the flight directors on the visual segment of this approach?


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