Originally Posted by Smythe
(Post 10494732)
rear tires flat, front landing gear impaled, reverse thrust still active...that must have been quite the landing....
In related news, United adds another aircraft to their A321XLR order at the Paris airshow..... :} |
According to meteo reports, the wind was 210/220 13/24 kt, direct headwind.
KEWR 151651Z 21016G24KT 10SM FEW140 SCT180 BKN250 27/09 A3005 RMK AO2 PK WND 20026/1553 SLP177 T02670094 KEWR 151658Z 22013G24KT 10SM FEW130 SCT180 BKN250 27/09 A3005 RMK AO2 T02720089 |
Anyone interested in waiting until the investigation is complete and facts are in ?
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I seem to remember Air Europe doing something similar at Funchal? I think it was said that the step down into the flight deck was changed to a step up!
It seems that while the 757 is very easy to de-rotate too quickly, giving a hard nose gear landing, it's not built to take those impacts. My recollection is that if you don't fly the nose gear onto the runway before the autobrake bites, you'll run out of elevator authority and can't prevent the nose slamming in? |
Originally Posted by ZeBedie
(Post 10494939)
I seem to remember Air Europe doing something similar at Funchal? I think it was said that the step down into the flight deck was changed to a step up!
It seems that while the 757 is very easy to de-rotate too quickly, giving a hard nose gear landing, it's not built to take those impacts. My recollection is that if you don't fly the nose gear onto the runway before the autobrake bites, you'll run out of elevator authority and can't prevent the nose slamming in? Carrying speed well in excess of Vref greatly enhances the chance of a nose wheel first or shallow touchdown and this looks a classic case of that. As someone said perhaps wait for the actual accident report. |
Originally Posted by Globocnik
(Post 10494953)
Carrying speed well in excess of Vref greatly enhances the chance of a nose wheel first or shallow touchdown and this looks a classic case of that. As someone said perhaps wait for the actual accident report. Why should people wait for the report in this particular case, while they don't when the accident occurs in another continent with foreing pilots ? We already do have some facts here : the wind, the state of the airplane. What we are still to read about, is the usual rigmarole of "should haves", "forgot flying basics", "substandard training", etc. |
Originally Posted by ZeBedie
(Post 10494939)
it's not built to take those impacts.
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any compression type buckling on top of the fuselage?
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https://en.wikipedia.org/wiki/Britan...ys_Flight_226A Here, nose wheel 'dog box' failed due over load, resulting in a significant runway excursion.
Final report https://www.fomento.es/NR/rdonlyres/..._texto_ENG.pdf Britannia was generally regarded as having 'high standards' within the industry at the time, a long established operator. However deep night flying (a Britannia Airways 'speciality' since inclusive tour charter flying really got going of the 70s) crew fatigue thought a possible contributing factor in this particular 1999 Boeing 757 accident. |
Originally Posted by DaveReidUK
(Post 10494973)
Are you suggesting that some other aircraft are capable of withstanding a similar impact without suffering structural deformation? What type(s) do you have in mind?
Illyushin. As as an aside I took a 757 in to Funchal shortly after the Air Europe incident ( our airline stopped 757 operations in to there shortly thereafter). I wandered over to see how the Boeing field engineers ( lots of pens in shirt pockets, crew cuts, and, I suspect, had cut their teeth in ‘Nam) , were fixing it. Jacked up the aircraft by using a pit prop through the dv windows. Drifted the nose gear down and welded it down. Then welded the now deformed window back in to the frame and then an AE crew flew it back gear down ( think they retracted the mains not sure ) to Luton. Built like a brick ****house. As all things Boeing were back in the day. However there are obviously limits. !! 😎😎😎 |
Noticing from the images, the starboard thrust reverser is still deployed, but the port is not.
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With regards to the post above, the Britannia incident pushed the dog box up just far enough to snag the thrust lever and reverser cables, but not symmetrically. Looks the same here.
I was, uh, rather close to that particular incident. |
The damaged 757 (I was inside it during the repairs, done by Boeing - Mr Hammer)
https://cimg3.ibsrv.net/gimg/pprune....86dc9c8d48.jpg https://cimg4.ibsrv.net/gimg/pprune....f3d1adbe2c.jpg |
Originally Posted by blue up
(Post 10495145)
With regards to the post above, the Britannia incident pushed the dog box up just far enough to snag the thrust lever and reverser cables, but not symmetrically. Looks the same here.
I was, uh, rather close to that particular incident. While the design of using the throttle cables to actuate the reverse DCV was common place back then, it has some highly undesirable failure modes. The 757-300/Rolls didn't use that design (I was directly involved in the design change, including having to debate the Chief Engineer who didn't want to make the change). In the aftermath, Boeing designed a 'guillotine' system - if the nose wheel came back as it did in Britannia, the guillotine was intended to cut the throttle cables in such a way that the engines would go to idle. I think the guillotine was AD'ed but I wouldn't swear to it. |
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Originally Posted by tdracer
(Post 10495173)
Not quite - there are not 'reverse cables' as such on the 757 - on the 757-200/RB211-535, the throttle cable actuates the reverser Directional Control Valve when it's moved sufficiently aft of forward idle. When the nose gear came back through the EE bay, it snagged the throttle cables in such a way that the engines went to high forward thrust - in that condition it is not possible to deploy the reversers. The combination of high thrust and inability to deploy the reversers made for a rather long overrun.
While the design of using the throttle cables to actuate the reverse DCV was common place back then, it has some highly undesirable failure modes. The 757-300/Rolls didn't use that design (I was directly involved in the design change, including having to debate the Chief Engineer who didn't want to make the change). In the aftermath, Boeing designed a 'guillotine' system - if the nose wheel came back as it did in Britannia, the guillotine was intended to cut the throttle cables in such a way that the engines would go to idle. I think the guillotine was AD'ed but I wouldn't swear to it. |
Originally Posted by bafanguy
(Post 10494935)
Anyone interested in waiting until the investigation is complete and facts are in ?
Cheers, Grog |
Originally Posted by bill fly
(Post 10495196)
That could have been a double edged sword (sorry...) TD if some poor wight had attempted a go around after initial impact... |
Originally Posted by bafanguy https://www.pprune.org/images/buttons/viewpost.gif Anyone interested in waiting until the investigation is complete and facts are in ? No. What would be the fun in that? Cheers, Grog |
Originally Posted by bill fly
(Post 10495196)
That could have been a double edged sword (sorry...) TD if some poor wight had attempted a go around after initial impact... |
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