CNN Reports FEDEX crash in Tokyo
Trash du Blanc
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Yes, I still fly them.
We have ~60 MD-11's and ~80 MD-10's.
The MD-10 is a former DC-10 with the MD-11 cockpit, new wiring and a few other improvements.
We have both "dash 10" and "dash 30" MD-10's.
The controversy was over the common type rating. Fedex MD-11 pilots also fly the MD-10.
Probably not a factor in this case, as the accident crew were PANC based, where there are no MD-10's.
Why did the aircraft bounce? Because it hit hard. Spoilers won't stop that.
Other than that, time will tell.
We have ~60 MD-11's and ~80 MD-10's.
The MD-10 is a former DC-10 with the MD-11 cockpit, new wiring and a few other improvements.
We have both "dash 10" and "dash 30" MD-10's.
The controversy was over the common type rating. Fedex MD-11 pilots also fly the MD-10.
Probably not a factor in this case, as the accident crew were PANC based, where there are no MD-10's.
Why did the aircraft bounce? Because it hit hard. Spoilers won't stop that.
Other than that, time will tell.
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By looking at the video link, it looks like he was just about to go into the flare mode bounced hard and then the tail lifted. It then looks like they tried to recuperate the nose down attitute but, to late as they then bounced hard (nose wheel first) loosing lateral control and flipping over. At 50' the throtles go into retard mode and as already mentioned if, the stabilizer was trimmed fully aft they would not have had much pitch control. The MD11 can be tricky with crossswinds and or wind shifts. As usual to speculate is not appropiate but, my comments are soley in reference to the video and my personal experience of 10 yeaars flying this aircraft.
Last edited by MPH; 23rd Mar 2009 at 15:03.
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The MD-11s handling issues are well established- so is its nasty prediliction for flipping over.
But that does not mean that such issues caused this crash- we will all have to wait.
However, Rainboe is not wrong - the thing is a mis-configured mess. Whatever the DC-10s problems, it had a huge, full authority tailplane (stabliser for our American readers) and this was reduced in area when the MD-11 was mutated from the DC-10.
Facts are that McDonnell Douglas justified the DC-10s oversized tailplane at launch with the aerodynamic area rule principal - and wind tunnel tests to establish control authority in a heavily flapped config. In fact so oversized was the DC-10- tailplane that it suffered from spar fatigue in the mid 1980s - a series of FAA / JAA inspections followed.
So the obvious question is, if they knew why they put such a large tailplane on the thing in the first place, what kind of logic prevailed to remove it for the MD-11- a fact made worse by the MD-11s fuselage stretch and consequent need for more elevator authority due to the change in the moment arm calculus..
So they knew....
Economic ruled the day- lighter tailplane, less weight, and a computer to control its incidence....
At American Airliens they MD-11 was called' the scud' as you never knew where it was going to land.
Oh and should we be criticising this Fed Ex pilot for attitude changes as per the video that we do not know the casue of? even if he did over control the nose angle inputs, what chance did he have? Very little.
My friends at KLM were masters of the MD-11 landing technique- esp crosswind -- but even they had to practise it regualrly- they knew you see...
Holding a glider off a bounced landing (as I sometimes do) and NOT moving the stick and allowing it to settle its phugoid out without a PIO is one thing, buth that theory aint going to work on an MD-11 chaps.
Over and out...
But that does not mean that such issues caused this crash- we will all have to wait.
However, Rainboe is not wrong - the thing is a mis-configured mess. Whatever the DC-10s problems, it had a huge, full authority tailplane (stabliser for our American readers) and this was reduced in area when the MD-11 was mutated from the DC-10.
Facts are that McDonnell Douglas justified the DC-10s oversized tailplane at launch with the aerodynamic area rule principal - and wind tunnel tests to establish control authority in a heavily flapped config. In fact so oversized was the DC-10- tailplane that it suffered from spar fatigue in the mid 1980s - a series of FAA / JAA inspections followed.
So the obvious question is, if they knew why they put such a large tailplane on the thing in the first place, what kind of logic prevailed to remove it for the MD-11- a fact made worse by the MD-11s fuselage stretch and consequent need for more elevator authority due to the change in the moment arm calculus..
So they knew....
Economic ruled the day- lighter tailplane, less weight, and a computer to control its incidence....
At American Airliens they MD-11 was called' the scud' as you never knew where it was going to land.
Oh and should we be criticising this Fed Ex pilot for attitude changes as per the video that we do not know the casue of? even if he did over control the nose angle inputs, what chance did he have? Very little.
My friends at KLM were masters of the MD-11 landing technique- esp crosswind -- but even they had to practise it regualrly- they knew you see...
Holding a glider off a bounced landing (as I sometimes do) and NOT moving the stick and allowing it to settle its phugoid out without a PIO is one thing, buth that theory aint going to work on an MD-11 chaps.
Over and out...
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So the obvious question is, if they knew why they put such a large tailplane on the thing in the first place, what kind of logic prevailed to remove it for the MD-11- a fact made worse by the MD-11s fuselage stretch and consequent need for more elevator authority due to the change in the moment arm calculus..
So MD presumably took advantage of that to reduce the surface area, to reduce profile drag.
That then upped the induced drag in mis-trimmed cruise conditions, requiring another drag reduction programme, involving amongst aother things, dynamic CoG movement, a la Concorde.
But then the downside! Low-speed and flapped control authority...
The original MD developments of the DC-10 were quite seriously below advertised range, always an uphill struggle to rectify when it's probably within the very nature of the beast.
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So the obvious question is, if they knew why they put such a large tailplane on the thing in the first place, what kind of logic prevailed to remove it for the MD-11- a fact made worse by the MD-11s fuselage stretch and consequent need for more elevator authority due to the change in the moment arm calculus..
When McDD designed the MD11 they kept the DC10 wing and put winglets on. The horizontal stab was reduced in size as it was clear that the DC10's stab was indeed too large and led to issues such as weight, drag & structural as outlined above. Launch customers said the a/c would not achieve its payload/range targets so they "tweaked" the wing with aerodynamic tricks. I believe LSAS was added during testing as a result of initial flight tests, but am not 100% sure.
The result was a reasonable product but one that required a deft hand on the stick
Last edited by DCDriver; 23rd Mar 2009 at 16:32. Reason: inserting quote
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I'm trying to understand the MD11 design. It has "relaxed" longitudinal stability, but has LESS stabilizer and elevator authority than the DC10. Then it also has an LSAS system to compensate for all of this. 
In looking at the video I posted earlier, I've only previously seen fighter aircraft stabilators work that hard on approach. Even though fighters are designed with "relaxed" longitudinal stability (for agility), they compensate with very large pitch authority (which helps in landings and the transonic region).
In looking at the video I posted earlier, I've only previously seen fighter aircraft stabilators work that hard on approach. Even though fighters are designed with "relaxed" longitudinal stability (for agility), they compensate with very large pitch authority (which helps in landings and the transonic region).
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DK FCI,
Post 114,
Scary stuff. If the x/wind landings don't get you, the electrical fires or high altitude upsets will.
Can't say I am too sorry not to have flown this "gem"
Post 114,
Scary stuff. If the x/wind landings don't get you, the electrical fires or high altitude upsets will.
Can't say I am too sorry not to have flown this "gem"
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CptPlaystation:
Quote: If the x/wind landings don't get you, the electrical fires or high altitude upsets will.
Wouldn't that be like saying the A320 is a computerized pos?! Cause if your inexperienced FO won't get you, the computer will?!
I've read some of your previos comments on different agendas and found them to be quite objective-respect.
Not this one though.
Quote: If the x/wind landings don't get you, the electrical fires or high altitude upsets will.
Wouldn't that be like saying the A320 is a computerized pos?! Cause if your inexperienced FO won't get you, the computer will?!
I've read some of your previos comments on different agendas and found them to be quite objective-respect.
Not this one though.
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Flight Safety
It has a lot to do with trim-drag and profile drag in the cruise... and then the low-speed consequences. Don't get sidetracked by relaxed stability, that was unlikely an original design goal - but became necessary to increase range.
This is a long story , and i bet a good few McD design aerod and project staff are grey or short of hair as a result.
It has a lot to do with trim-drag and profile drag in the cruise... and then the low-speed consequences. Don't get sidetracked by relaxed stability, that was unlikely an original design goal - but became necessary to increase range.
This is a long story , and i bet a good few McD design aerod and project staff are grey or short of hair as a result.
Airbubba: Your link in #118 is "deja vu all over again"!
Video from Narita is eerily reminiscent of the Sioux City DC-10 crash video - one wing vertical, the other trailing a sheet of flame off the side of the runway after a loss of control. (And, yes, I know the situations were otherwise very different!)
Video from Narita is eerily reminiscent of the Sioux City DC-10 crash video - one wing vertical, the other trailing a sheet of flame off the side of the runway after a loss of control. (And, yes, I know the situations were otherwise very different!)
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act700, just seems to me that , either by failure to achieve adequate training, or , in the case of the electrics by design or legislation, that these 3 "nasties" have been a bit repetitive to be brushed off. Think I would leave the last word with Moody Blue, but his excellent post has "vanished" 
I absolutely loved my time on the DC-10. It was a delightful aeroplane to fly - a real pilot's aeroplane. It was easy to land nicely and it was excellent in a strong crosswind (wing-down technique) and in rough conditions.
Later in my flying career, I spent a lot of time with a CAA examiner (from another European authority) who had a lot of MD-11 time and I was amazed to hear (over several beers) how they had screwed up a really nice flying aeroplane by trying to save money by chopping down the size of the horizontal stabiliser and so ended up having to fit a computer (LSAS) and God knows what else to make good this defecit.
(As a matter of interest, the span of the DC-10 horizontal stabiliser (tailplane) was the same as the wingspan of the DC-3).
It was quite difficult to bounce the DC-10 but it might be of interest to know that the recovery technique was to ease (and I mean ease) forward on the control column. This might not work well on an MD-11?
My guess is that the start of this accident might well have begun with windshear at a very late stage on finals; too late to prevent a heavy landing.
Later in my flying career, I spent a lot of time with a CAA examiner (from another European authority) who had a lot of MD-11 time and I was amazed to hear (over several beers) how they had screwed up a really nice flying aeroplane by trying to save money by chopping down the size of the horizontal stabiliser and so ended up having to fit a computer (LSAS) and God knows what else to make good this defecit.
(As a matter of interest, the span of the DC-10 horizontal stabiliser (tailplane) was the same as the wingspan of the DC-3).
It was quite difficult to bounce the DC-10 but it might be of interest to know that the recovery technique was to ease (and I mean ease) forward on the control column. This might not work well on an MD-11?
My guess is that the start of this accident might well have begun with windshear at a very late stage on finals; too late to prevent a heavy landing.
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The LSAS was an example of designers running to stand still.
The fly-by-wire 777 and Airbus types were getting way ahead and the flying qualities could be tweaked electronically during flight test.
The MD-11 belonged to that intermediate generation like the A310/A300-600, not fully manual but not fully computer controlled, which scared many.
There are defenders of the old way, and many FBW supporters, but few I think who prefer the 'half way house'.
The fly-by-wire 777 and Airbus types were getting way ahead and the flying qualities could be tweaked electronically during flight test.
The MD-11 belonged to that intermediate generation like the A310/A300-600, not fully manual but not fully computer controlled, which scared many.
There are defenders of the old way, and many FBW supporters, but few I think who prefer the 'half way house'.
Last edited by Dysag; 23rd Mar 2009 at 17:20.
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The result is very much like Faro.
Rog 747,
You are right to refer to Faro, there control was lost , one of the main gears gave away and the wing came of , thereafter the aircraft rolled over. Why control was lost will be the issue to investigate. I 'am afraid the small stab. on the long MD 11 fuselage is playing a important role in the loss of control.
In 1994 a MD 11 at SMX. was nearly lost after control problems with the stab.and available landing distance. Here a aborted landing was made which saved the plane and pax. The aborted landing was made after selecting reverse thrust. Luckily the engines spooled up evenly.
Good Flying!
John
You are right to refer to Faro, there control was lost , one of the main gears gave away and the wing came of , thereafter the aircraft rolled over. Why control was lost will be the issue to investigate. I 'am afraid the small stab. on the long MD 11 fuselage is playing a important role in the loss of control.
In 1994 a MD 11 at SMX. was nearly lost after control problems with the stab.and available landing distance. Here a aborted landing was made which saved the plane and pax. The aborted landing was made after selecting reverse thrust. Luckily the engines spooled up evenly.
Good Flying!
John
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Is the roll over not caused by the left wing stalling.
The tip then impacting the side of the runway, quickly followed by the engine breaking off with the wing.
The tip then impacting the side of the runway, quickly followed by the engine breaking off with the wing.
It's not so much the tip which causes the problem. The MD11 gear is designed to break off under horizontal impact but not vertical. If the vertical stress is high enough, it breaks the rear wing spar. The opposing forces (good wing still lifting, engine on bad wing already on runway) cause the wing to fold at the main-gear point, between engine and fuselage. Once that happens there's nothing to stop the aircraft rolling inverted.
Once on its back it stays there because the other wing hasn't been weakened by gear impact stress. Very similar inversion dynamics in the Mandarin and previous FedEx accidents.
The issue is how to avoid banging the thing on the deck in the first place.
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Am I right in thinking that the MD11 has a couple of features to assist in the lowering of the nose-wheel upon touch down?
-Ground spoilers deploy only initially to 45deg until the nose-wheel strut is compressed, then the spoiler handle continues to the 60deg (full position).
-Engine 2 is limited to idle reverse until the nose-wheel strut is compressed.
Is this correct?
-Ground spoilers deploy only initially to 45deg until the nose-wheel strut is compressed, then the spoiler handle continues to the 60deg (full position).
-Engine 2 is limited to idle reverse until the nose-wheel strut is compressed.
Is this correct?
