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AF356 tailstrike in yyz

Old 22nd Jan 2024, 20:53
  #21 (permalink)  
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I was on a flight as well and was watching nose wheel cam. The flare was quite long and the go around was initiated just before the nose wheel touch down. I did not notice tail strike but I thought reversers were actuated for brief moment. Could explain lack of thrust during rotation as there is definitely some delay if it went to reverse. From a Live ATC archive file - Departure freq 21:30z (approx 06:00) the pilot said they wanted to avoid long landing. I can confirm that on PA he said it was due to occupied runway. Funny thing was that the captian was standing by door saying bye to passengers as if nothing happened. Maybe he did not notice tail strike as well 🙈
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Old 22nd Jan 2024, 20:53
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flyrealtraffic.com not showing any ground targets that might have been in the way. ADS-B ground coverage at YYZ is gapless, so if whatever was on the runway had an ADS-B transponder it would show up here.

Perhaps a goose walking across.






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Old 22nd Jan 2024, 20:55
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'Never go around after selecting reverse', is what manuals say. Possibly PM pulled sidestick too? Both inputs added together.... Lets see!

Last edited by goeasy; 22nd Jan 2024 at 21:17. Reason: added quotes
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Old 22nd Jan 2024, 21:25
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Similar event here :
https://assets.publishing.service.go...XWBC_09-22.pdf

The root cause to me appears clearly on the plots page.
The elevators show a clear triangle shape. This means the elevator are chasing a target they can't reach, at maximum speed. This basically means PIO.
Why is there PIO ?
Because the pilot pulled, and noticed a reaction that was too large. He was convinced that the reaction was too large especially when the tail hit... So he pushed forward at maximum, and induced the PIO.

Why did the pilot pull too much ? Because if you look closely, there is a huuuge delay (in the order of one second) between the pilot pulling and the elevators going up.
So the pilot maintains his order longer than he would have, if the plane had reacted. It can also happen that when noticing the absence of reaction, he increases his order (maybe not the case here? look at the curves and see for yourself!). If he maintains his order, the time average of the order that is used in the flight control computer will increase and the elevator will go nose up... Too far nose up. Hence an airplane overreaction, and the subsequent induction of PIO.

Here, with only two full triangles visible, it's a short PIO. But the PIO is just a symptom of the PIO conditions being present. And only the onset of PIO, which is an airplane overraction, is enough for the plane to strike its tail.

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Old 22nd Jan 2024, 21:29
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Originally Posted by FUMR
Impossible to say accurately with FR24 but it could well have been a tad late vacating the runway.
FR24 replay is an absolute shamble.

If there was anything on or near the runway when AFR356 was touching down, it wasn't the preceding GLEX.
21:34:04 was the GLEX's first timestamp (well) beyond the holdingpoint line



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Old 22nd Jan 2024, 21:36
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They said it was "to avoid long landing" (much like the BA incident shown).. Heard on liveATC.
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Old 22nd Jan 2024, 22:23
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Originally Posted by DIBO
FR24 replay is an absolute shamble.
The replay facility on FR24 has always been pretty iffy - the only way to judge separation accurately is to download the respective ADS-B tracks and compare them.

But that's not an option in this case as the GLEX, like most of its ilk, doesn't have downloadable data on FR24.
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Old 23rd Jan 2024, 02:40
  #28 (permalink)  
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Originally Posted by CVividasku
They said it was "to avoid long landing" (much like the BA incident shown).. Heard on liveATC.
The touchdown was not long, and the crew went immediately after touchdown to GA thrust. They had ample room to do the GA and they were not outside of the landing zone, something spooked them into tossing away the landing, and why they wanted that attitude on the departure will be an interesting discussion.
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Old 23rd Jan 2024, 04:15
  #29 (permalink)  
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Originally Posted by meleagertoo
Ah! In YYZ was it! Now some know and the rest of us haven't a clue.
How about using real names instead of esoteric codes to show how clever (not) and 'insider' you are.

Has it not occurred that people who don't operate in that area will have no idea where that is?
Not all of us have a global list of IATA codes in our heads.
Sorry pumpkin what part of the name of the website you are on passed your ever so observant eye.
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Old 23rd Jan 2024, 06:08
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Originally Posted by Paul2
I was on the flight. Once the flight was stabilised after the go around, the pilot announced that the reason for the go around was that the runway was occupied…. How can we know what was on the runway?
I think one should take this announcement with a grain of salt ...

Small digression: a friend was on a Company flight to JFK around 11 October 2010. He wrote this: "the pilot approached the runway [...] at the last minute (I mean we were already above the runway), he pushes all power in and aborts the landing sequence [...] At the end of the pilot said that he apologizes but the runaway was occupied and he had to abort [...] the A380 has tail camera and from what I could see there was nothing on the runway [...]"

That particular event got some attention, on this forum and elsewhere ...
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Old 23rd Jan 2024, 08:12
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Why are the scrape marks off center?
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Old 23rd Jan 2024, 08:16
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Originally Posted by tiny.flame2771
Why are the scrape marks off center?
runway camber...

C. Coriolis

Last edited by fdr; 23rd Jan 2024 at 08:56.
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Old 23rd Jan 2024, 08:29
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Originally Posted by Paul2
I was on the flight. Once the flight was stabilised after the go around, the pilot announced that the reason for the go around was that the runway was occupied…. How can we know what was on the runway?
Originally Posted by Intrance
I'd hope the decision to go around due to an occupied runway would come a bit before touchdown on a seemingly severe CAVOK day with great visibility to see this other traffic occupying the runway... No need to put it down first and then second guess if the guy in front has vacated yet or not.

Sounds a bit strange to me, but let's see if any reports come out later. ...
In the UK you will not be cleared to land if the runway area is still occupied (and that includes aeroplanes that are vacating on the taxiway but not yet past the Cat 1 Hold).

In CDG you can be cleared to land when not only the aeroplane on the runway has not yet vacated, but the one ahead of you has not even landed yet.

Could someone let us know when you get your clearance to land in Canada?

We teach students in light aeroplanes to go around from a safe height if the runway is still occupied. Why would you land an airliner if the runway is still occupied? Something doesn't add up! Any formal reports will be interesting.
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Old 23rd Jan 2024, 08:41
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In the UK you will not be cleared to land if the runway area is still occupied (and that includes aeroplanes that are vacating on the taxiway but not yet past the Cat 1 Hold).

In CDG you can be cleared to land when not only the aeroplane on the runway has not yet vacated, but the one ahead of you has not even landed yet.

Could someone let us know when you get your clearance to land in Canada?
You can get a land-after clearance in the UK. Not sure I'd continue to the point of touch down if there was still traffic on the runway, but the decision can certainly be made up to and including that point. I don't think Canada does that awful thing like in the USA by clearing you to land while still in oceanic airspace (I'm being facetious, but you know what I mean). I've certainly never noticed it.

What concerns me about this video is that reverse thrust is clearly audible for several seconds in the clip.
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Old 23rd Jan 2024, 08:58
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Originally Posted by physicus

Perhaps a goose walking across.
Surely that would be a CYQX problem
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Old 23rd Jan 2024, 09:48
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Originally Posted by fdr
The touchdown was not long, and the crew went immediately after touchdown to GA thrust. They had ample room to do the GA and they were not outside of the landing zone, something spooked them into tossing away the landing, and why they wanted that attitude on the departure will be an interesting discussion.
I explained everything but you don't believe me.
They're telling in on the radio that the cause was a long landing. They touched down slightly after the 600m mark. Some airlines won't allow pilots to touch "in the TDZ" which can sometimes extend for more than one kilometer.

Why they pulled so hard is probably explained here :
AF356 tailstrike in yyz

Although the AAIB report doesn't explicitly identify the elevator delay and PIO, as a contributing factor, they are clearly visible on the curves. If we get curves for this incident, I expect to see a similar thing. I don't think they've updated the flight control laws between the two incidents.
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Old 23rd Jan 2024, 12:11
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Easy fix

They could repair the damage by wrapping the rear fuselage in silver tape . Afterwards it would look a lot like F-WWCF.


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Old 23rd Jan 2024, 18:49
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Originally Posted by goeasy
'Never go around after selecting reverse', is what manuals say. Possibly PM pulled sidestick too? Both inputs added together.... Lets see!
Does Airbus actually say "Never"?
Boeing has a similar statement, but it's somewhat weasel worded - IIRC it's along the line of "Go around after selecting reverse is not recommended" - it doesn't say "never".
If you touchdown, select reverse, then discover another aircraft/vehicle blocking the runway, you have pretty limited options...
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Old 23rd Jan 2024, 19:24
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Airbus: “Thrust reverser selection is a decision to stop.”

Furthermore:

The SOP for landing also states that as soon as the flight crew selects reverse thrust, they must perform a full-stop landing. This is also highlighted for a go-around near the ground in the FCTM, which states, “the PF must not initiate a go-around after the selection of the thrust reversers.”
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Old 23rd Jan 2024, 20:14
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Boeing has a similar statement, but it's somewhat weasel worded - IIRC it's along the line of "Go around after selecting reverse is not recommended" - it doesn't say "never".
I thought it became "never" after the Cranbrook 737 crash, where the crew tried to go around, after selecting reverse thrust, when they discovered a snowplow on the runway. The FO was a friend of mine.

https://en.wikipedia.org/wiki/Pacifi...nes_Flight_314
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