Fedex Tokyo MD-11 Update
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Fedex Tokyo MD-11 Update
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I was impressed with the after crash photos of the LG. Instead of piercing the top surface of the wing's skin, the wing came off. This company built a/c for the Navy, and they were very stout. The engineering of the LG is extensive, and it seems (perhaps just a useless observation) that the LG can survive just about anything. But, why should it? That mammoth Beast can 'Bounce' ? Even the Nose Gear remained in position. Did anyone catch that last Bounce on the NG? Criminy.
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The MLG are directly attached to the aft spar - no substructure that can give a little. So 3g+ landings are going to fracture the spar. Watch the video - BOTH wings were broken, the other one folds over the fuselage as it rolls.
But any heavy aircraft is going to get creamed in such a scenario. The MD11 just does it alot more spectacularly.
But any heavy aircraft is going to get creamed in such a scenario. The MD11 just does it alot more spectacularly.
The reduction in size of the horizontal stabiliser (versus the DC10 to save weight) has been discussed at length on this forum together with the electronics that were supposed to compensate. Given the regularity of landing accidents one wonders what went on during the original flight testing. I cannot believe the test pilots had no inkling.
Then again I know people who flew the diva (as she is sometimes called over here) without incident for years and were very surprised by the statistics showing the amazing difference in accidents between the MD11 and similar jets. I remember being ridiculed for highlighting this disparity on Pprune some time ago, until a very helpful gentleman from Finland pointed out that the statistics were published by Boeing, who have no interest in trying to make the MD11 look bad, as they took over the company.
Then again I know people who flew the diva (as she is sometimes called over here) without incident for years and were very surprised by the statistics showing the amazing difference in accidents between the MD11 and similar jets. I remember being ridiculed for highlighting this disparity on Pprune some time ago, until a very helpful gentleman from Finland pointed out that the statistics were published by Boeing, who have no interest in trying to make the MD11 look bad, as they took over the company.
It seems odd that no other commercial aircraft (to my knowledge) has ended up on its back but this one has done so on several occasions - especially as there are/were so few in service.
It is hardly a surprise that almost everyone has stopped flying them with passengers. The irony is that due to the nature of the cargo business most will now be touching down close to max landing weight exacerbating the speed and handling problems.
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It is interesting to not that
a) The MD-11F has only about 60% of the range of the passenger versions, so it probably has a higher MLW.
b) All of the landing / bouncing accidents were F
a) The MD-11F has only about 60% of the range of the passenger versions, so it probably has a higher MLW.
b) All of the landing / bouncing accidents were F
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Not wanting to appear boasting, but I flew the MD11 13 years and had no problem with it.
Look at the statistics and you will realise that during the initial years of operation there were very few incidents. The reason is that the crew came mostly from DC10 or MD80, they were well experienced in pitch and power management and a rather steep climb of the speed/drag curve below Vref.
Once seniority started shifting pilots from the new generation of A320 aircraft, where pitch and power and trimming is no longer really emphasized, the problems started.
The reaction of MD/Boeing was implementing more and more input inhibits as to counteract the loss of piloting skills, they only aggravated the situation by castrating the controls.
I am not saying that the MD11 was the best aerodynamical achievement, although it has the by far best cockpit layouts and logic, it was an aircraft that was manageable for a properly trained pilot. The Boeing bulletin now tries to achieve just that.
The problem is that too many of todays pilots came through the new automation religion and are simply lacking the basic skills of flying. A simple bulletin, a sim session or two and some well intended but cheap words of a chief instructor will not suffice imho.
The MD11 is out of our time. But I loved it.
(by the way, the bounced landing crash in Hong Kong by ChEa WAS a passenger airplane)
Look at the statistics and you will realise that during the initial years of operation there were very few incidents. The reason is that the crew came mostly from DC10 or MD80, they were well experienced in pitch and power management and a rather steep climb of the speed/drag curve below Vref.
Once seniority started shifting pilots from the new generation of A320 aircraft, where pitch and power and trimming is no longer really emphasized, the problems started.
The reaction of MD/Boeing was implementing more and more input inhibits as to counteract the loss of piloting skills, they only aggravated the situation by castrating the controls.
I am not saying that the MD11 was the best aerodynamical achievement, although it has the by far best cockpit layouts and logic, it was an aircraft that was manageable for a properly trained pilot. The Boeing bulletin now tries to achieve just that.
The problem is that too many of todays pilots came through the new automation religion and are simply lacking the basic skills of flying. A simple bulletin, a sim session or two and some well intended but cheap words of a chief instructor will not suffice imho.
The MD11 is out of our time. But I loved it.
(by the way, the bounced landing crash in Hong Kong by ChEa WAS a passenger airplane)
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@Gretchenfrage
Not that I'm debating overall current basic piloting skills but I fail to see
where this is relavant with the MD-11's history of repeated tendencies
to flip on its back after a hard TD.
As far as I'm aware the 2 FX crews and the Mandarin airlines flight where all old school pilots comming of the old bus and the 727.
where this is relavant with the MD-11's history of repeated tendencies
to flip on its back after a hard TD.
As far as I'm aware the 2 FX crews and the Mandarin airlines flight where all old school pilots comming of the old bus and the 727.
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my understanding is that the design was compromised by the launch customer(Delta) shortening the wing span to fit the then new maintenance hangar.Ultimately leading to the aircraft having very high Vref speeds.
Out off the hands of the test pilots.
Out off the hands of the test pilots.
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I work for FX and have flown the Mighty Dog "F" for 7 years total at two different companies.
In both of our MD11 hull losses I can assure you that pilot experience was not a factor. The pilots were well-rounded with plenty of heavy, high-performance time, as well as a fair amount of MD11 time.
The KEWR hull loss occurred back before the software change, when LSAS kicked off below 50'. The captain set up an excessive sink rate then lacked the pitch authority to arrest it adequately.
Much speculation follows - no word from the Japanese yet:
The RJAA hull loss involved a huge wind gust at touchdown, a big bounce and (I believe) a first officer that thought he was on the ground when he wasn't. This is all speculation but if you look at the pitch control inputs it does look like he was trying to derotate and "stick" the aircraft on the runway. His pitch-down input set up rotational inertia in pitch that could not be overcome, causing the nose-down touchdown. The second touchdown was at less than one g until ground contact, causing a whipsaw effect on the wings, right at the MLG attach point.
One cannot forget the overwhelming fatigue they were suffering from at that point. They left the Philippines the night before, stopped at Guangzhao for a few hours then arrived at Narita well after sunrise. This with a two-man crew that had started in Anchorage just a few days before. I've been in that type of situation, and intellectual agility is not available. You're hanging in the straps, just waiting for the pain to stop at the hotel room.....
In both of our MD11 hull losses I can assure you that pilot experience was not a factor. The pilots were well-rounded with plenty of heavy, high-performance time, as well as a fair amount of MD11 time.
The KEWR hull loss occurred back before the software change, when LSAS kicked off below 50'. The captain set up an excessive sink rate then lacked the pitch authority to arrest it adequately.
Much speculation follows - no word from the Japanese yet:
The RJAA hull loss involved a huge wind gust at touchdown, a big bounce and (I believe) a first officer that thought he was on the ground when he wasn't. This is all speculation but if you look at the pitch control inputs it does look like he was trying to derotate and "stick" the aircraft on the runway. His pitch-down input set up rotational inertia in pitch that could not be overcome, causing the nose-down touchdown. The second touchdown was at less than one g until ground contact, causing a whipsaw effect on the wings, right at the MLG attach point.
One cannot forget the overwhelming fatigue they were suffering from at that point. They left the Philippines the night before, stopped at Guangzhao for a few hours then arrived at Narita well after sunrise. This with a two-man crew that had started in Anchorage just a few days before. I've been in that type of situation, and intellectual agility is not available. You're hanging in the straps, just waiting for the pain to stop at the hotel room.....
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I did not specifically pretend that the crews involved were former AB pilots and inexperienced.
I described a trend that led to the MD11 being decried difficult.
The tendency to flip on its back after bounced landings originates due to the partial deployment of the spoilers after wheel spin-up (first contact). If this occurs hard and a bounce follows, the aircraft hangs in the air with mostly quite high pitch and thrust idle. As I mentioned, the MD11 has a particularly steep rise of the speed/drag curve below Vref, therefore stalling rapidly in this situation. One wing does this first (mainly downwind) and a marked banking occurs and the wing touches the ground leading to the flip.
Remedy was to select one notch less flaps (still landing configuration) or keep the Vapp, or even Vapp+5 down to TD. This is however not always desired, as the Vapp were already very high with full flaps. Not really what you'd like especially on shorter runways (i.e. the one in NRT), those less than 2500m were not very appreciated with this bird.
Another very important remedy is a ultra strict flight path adherence on short final. This assured a much more constant pitch and trim configuration. You needed to assist/override the AT to keep a precise approach speed adherence, less to the upper side, but absolute to the lower. That is exactly where Airbus pilots were less precise (in my experience), their former birds (I have flown them as well) are much less delicate in this respect. The speeds were lower, they mostly flew fixed throttles and the Airbus' are less traitorous when slightly below Vref.
I described a trend that led to the MD11 being decried difficult.
The tendency to flip on its back after bounced landings originates due to the partial deployment of the spoilers after wheel spin-up (first contact). If this occurs hard and a bounce follows, the aircraft hangs in the air with mostly quite high pitch and thrust idle. As I mentioned, the MD11 has a particularly steep rise of the speed/drag curve below Vref, therefore stalling rapidly in this situation. One wing does this first (mainly downwind) and a marked banking occurs and the wing touches the ground leading to the flip.
Remedy was to select one notch less flaps (still landing configuration) or keep the Vapp, or even Vapp+5 down to TD. This is however not always desired, as the Vapp were already very high with full flaps. Not really what you'd like especially on shorter runways (i.e. the one in NRT), those less than 2500m were not very appreciated with this bird.
Another very important remedy is a ultra strict flight path adherence on short final. This assured a much more constant pitch and trim configuration. You needed to assist/override the AT to keep a precise approach speed adherence, less to the upper side, but absolute to the lower. That is exactly where Airbus pilots were less precise (in my experience), their former birds (I have flown them as well) are much less delicate in this respect. The speeds were lower, they mostly flew fixed throttles and the Airbus' are less traitorous when slightly below Vref.
Wrong.
The tendency for it to flip on its back is due to the undercarriage being anchored directly into the main spar so a hard landing rips one wing off. The situations you describe are probably true but they account for the hard landings, the subsequent roll overs are due to one wing falling off due to the hard landing.
Look at the BA777, bits of u/c everywhere including up through the wing but both wings are still firmly attached to the a/c. Now look at all the MD-11 roll overs, you'll find one wing a long way from the rest of the wreckage in all cases.
The tendency for it to flip on its back is due to the undercarriage being anchored directly into the main spar so a hard landing rips one wing off. The situations you describe are probably true but they account for the hard landings, the subsequent roll overs are due to one wing falling off due to the hard landing.
Look at the BA777, bits of u/c everywhere including up through the wing but both wings are still firmly attached to the a/c. Now look at all the MD-11 roll overs, you'll find one wing a long way from the rest of the wreckage in all cases.
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Narita Rwy 34L
Not really what you'd like especially on shorter runways (i.e. the one in NRT), those less than 2500m were not very appreciated with this bird.