Lufthansa cargo plane crash
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So its perfectly forgiving in the hands of an experienced Test Pilot.
Impressive ...
But I don't want to get into a slugging match. The MD11 is as dangerous or not as modern competitors. Untrained or bad pilots crash any one of those.
Maybe some models need more training when in upsets, the MD11 needs more for the final approach.
What do you prefer, what is more easy to handle??
DOVE
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Sirs
I have flown the MD11 from 1994 to year 2000, and for two different airlines.
I’ll try to summarize my experience with her. Landing that beast is tricky from 50’ down.
At that point the autothrottle begins gradually to retard the engines to idle. This means that the flare, if for any reason the threshold speed was too low, had to be more carefully processed.
That’s the reason why someone developed the habit to disengage the autothrottle in a very short final and to manually retard the engines to idle when needed.
The second deception comes when the main wheels spin up. At that moment the spoiler panels on the wing upper surfaces come up producing an abrupt and strong pitch-up moment.
So: the pilot was exerting a pull force on the control column for the flare, and in a split second he has to revert the effort on the elevator, pushing it down, in order not to contact the tail on the runway.
Now imagine what happens if someone (PF or PNF/Cpt) pushes hard the column forward as usual, but either the aircraft is not yet on the ground (convinced that it is), or it bounced (and the feeling is that the mains are firmly on the ground).
The nose wheel collapses on the land and… We all know the remnant of the story, written so many time.
Those are my two cents.
And I long for someone to correct me.
I have flown the MD11 from 1994 to year 2000, and for two different airlines.
I’ll try to summarize my experience with her. Landing that beast is tricky from 50’ down.
At that point the autothrottle begins gradually to retard the engines to idle. This means that the flare, if for any reason the threshold speed was too low, had to be more carefully processed.
That’s the reason why someone developed the habit to disengage the autothrottle in a very short final and to manually retard the engines to idle when needed.
The second deception comes when the main wheels spin up. At that moment the spoiler panels on the wing upper surfaces come up producing an abrupt and strong pitch-up moment.
So: the pilot was exerting a pull force on the control column for the flare, and in a split second he has to revert the effort on the elevator, pushing it down, in order not to contact the tail on the runway.
Now imagine what happens if someone (PF or PNF/Cpt) pushes hard the column forward as usual, but either the aircraft is not yet on the ground (convinced that it is), or it bounced (and the feeling is that the mains are firmly on the ground).
The nose wheel collapses on the land and… We all know the remnant of the story, written so many time.
Those are my two cents.
And I long for someone to correct me.
It can be flown safely, with caution..
I have flown the MD-11 for some 4000 hrs, until 2004. In both passenger and cargo ops.
I enjoyed flying it, but it is an airplane you have to be careful with when landing.
When designing the MD-11, McDonnell Douglas reduced the size of the horizontal stabilizer compared to its predecessor DC-10, for fuel efficiency reasons.
Obviously, this reduced pitch authority to a certain extent. To compensate, LSAS was installed which has been described before. It is basically a horizontal yaw damper with a few additional softwaremodes.
After a number of tail strikes and hard landings, they added a nose-lowering mode to it. It trims the nose down after touchdown. That helped somewhat.
My experience; especially when flaring a bit late, it can surprise you by further pitching up after touchdown. Requiring a good push on the yoke to avoid a tail strike.
During the first few years that my company operated the MD-11, I have seen, and also made
, nearly full nose down inputs on the yoke, to the stops. I had never seen that on any other airplane before, nor have I seen it since.
Since then, we, the pilots, have learned to deal with this airplane’s peculiarities, and my company has not had any tail strikes or landing accidents. And hopefully it stays that way, as we still operate it. I’m sure luck has played a part in that record.
LH, FX, DL & others that have had MD-11 accidents are professional airlines with carefully selected pilots, and I’m sure they train them properly. So if these airlines have significantly more incidents and accidents with this airplane type and not with others, it must be the airplane that is different. I don’t think there is much doubt about this. The accident statistics speak for themselves.
The smaller horizontal stab gives you somewhat less control, especially at lower speeds with full flaps.
On top of that, I believe the airplane has more longitudinal inertia, due to the tail engine. That heavy engine takes time to start moving up or down.
I also wonder if the gyroscopic effects of that tail engine play a roll in this inertia.
Regardless, it requires more force to make it pitch up or down. Combined with the smaller horizontal stab, it makes pitch changes take longer than you are used to.
Let’s look at the landing.
Assume you flare a bit on the late side. Realizing this, you pull up a bit more than usual. However, due to the longitudinal inertia and smaller stab, this takes longer than you are used to. So you wonder if something is ever going to happen, and pull a bit more. Finally, the airplane begins to react; it will start to pitch up. The mains touch down. But the pitch rate will continue after touchdown due to the longitudinal inertia, added by the pitch up tendency caused by the spoilers. So a good push is needed to avoid a tail strike. Lowering the nose again takes time, perhaps causing more pitch down input than needed. When you finally get a downward pitch rate, you have to stop it again before putting the nose gear through the runway.
This is a perfect recipe up for a PIO, Pilot Induced Oscillation, which is what we have seen on several MD-11 accidents.
Anyone who has flown the MD-11 will recognize it.
This PIO is even more dangerous if you have bounced, and become airborne after the first touchdown. A go around is the only safe recovery out of this situation.
But what if you don’t realize that you bounced? Apparently, that is not as easy as it sounds, because several crews didn’t recognize being airborne again.
I don’t pretend to have an easy solution for this tricky airplane characteristic.
I don’t see a technical solution, because you cannot do anything about that horizontal stab and the tail engine. We are talking about a twenty odd year old airplane here. For Boeing it is a ‘heritance’ model, and I’m sure they would love to get rid of supporting it. They do so hesitantly now. With it's high accident rate, they probable see it as a liability.
Installing HUD's then, as proposed by the Saudi Accident board? I doubt if they would be effective. Things happen quickly during landing, instinctive reflexes take over. Reflexes that were developed on other, more benign, airplanes.
An obvious start would be bounce recognition and recovery procedure training, as several airlines do. Not only during initial-, but also during recurrent training.
Briefing this procedure during every approach briefing would help to reinforce awareness of this tricky airplane behavior.
Experience on the airplane certainly helps, as I did not see full control inputs anymore after those early years. That means that anyone who has fewer than, say, a few years on the airplane has to stay extra vigilant. And the pilot next to him/her as well.
And don’t think twice about going around.
For the mindset, it might help to always take along enough fuel for an - extra - go around (on top of the std 30 mins final reserve). That way going around becomes a bit more carefree.
An extra expense, for sure. But accidents or incidents are more expensive.
I once read a beautiful suggestion on PPRuNe; a bottle of wine each for pilots that made a go around, no questions asked. With compliments, from the MFO. FDM will take care of everything else.
Bottom line; even though the MD-11 is an airplane with certain peculiarities, it can be flown safely by experienced and professional crews.
But be careful landing it.
I enjoyed flying it, but it is an airplane you have to be careful with when landing.
When designing the MD-11, McDonnell Douglas reduced the size of the horizontal stabilizer compared to its predecessor DC-10, for fuel efficiency reasons.
Obviously, this reduced pitch authority to a certain extent. To compensate, LSAS was installed which has been described before. It is basically a horizontal yaw damper with a few additional softwaremodes.
After a number of tail strikes and hard landings, they added a nose-lowering mode to it. It trims the nose down after touchdown. That helped somewhat.
My experience; especially when flaring a bit late, it can surprise you by further pitching up after touchdown. Requiring a good push on the yoke to avoid a tail strike.
During the first few years that my company operated the MD-11, I have seen, and also made
, nearly full nose down inputs on the yoke, to the stops. I had never seen that on any other airplane before, nor have I seen it since. Since then, we, the pilots, have learned to deal with this airplane’s peculiarities, and my company has not had any tail strikes or landing accidents. And hopefully it stays that way, as we still operate it. I’m sure luck has played a part in that record.
LH, FX, DL & others that have had MD-11 accidents are professional airlines with carefully selected pilots, and I’m sure they train them properly. So if these airlines have significantly more incidents and accidents with this airplane type and not with others, it must be the airplane that is different. I don’t think there is much doubt about this. The accident statistics speak for themselves.
The smaller horizontal stab gives you somewhat less control, especially at lower speeds with full flaps.
On top of that, I believe the airplane has more longitudinal inertia, due to the tail engine. That heavy engine takes time to start moving up or down.
I also wonder if the gyroscopic effects of that tail engine play a roll in this inertia.
Regardless, it requires more force to make it pitch up or down. Combined with the smaller horizontal stab, it makes pitch changes take longer than you are used to.
Let’s look at the landing.
Assume you flare a bit on the late side. Realizing this, you pull up a bit more than usual. However, due to the longitudinal inertia and smaller stab, this takes longer than you are used to. So you wonder if something is ever going to happen, and pull a bit more. Finally, the airplane begins to react; it will start to pitch up. The mains touch down. But the pitch rate will continue after touchdown due to the longitudinal inertia, added by the pitch up tendency caused by the spoilers. So a good push is needed to avoid a tail strike. Lowering the nose again takes time, perhaps causing more pitch down input than needed. When you finally get a downward pitch rate, you have to stop it again before putting the nose gear through the runway.
This is a perfect recipe up for a PIO, Pilot Induced Oscillation, which is what we have seen on several MD-11 accidents.
Anyone who has flown the MD-11 will recognize it.
This PIO is even more dangerous if you have bounced, and become airborne after the first touchdown. A go around is the only safe recovery out of this situation.
But what if you don’t realize that you bounced? Apparently, that is not as easy as it sounds, because several crews didn’t recognize being airborne again.
I don’t pretend to have an easy solution for this tricky airplane characteristic.
I don’t see a technical solution, because you cannot do anything about that horizontal stab and the tail engine. We are talking about a twenty odd year old airplane here. For Boeing it is a ‘heritance’ model, and I’m sure they would love to get rid of supporting it. They do so hesitantly now. With it's high accident rate, they probable see it as a liability.
Installing HUD's then, as proposed by the Saudi Accident board? I doubt if they would be effective. Things happen quickly during landing, instinctive reflexes take over. Reflexes that were developed on other, more benign, airplanes.
An obvious start would be bounce recognition and recovery procedure training, as several airlines do. Not only during initial-, but also during recurrent training.
Briefing this procedure during every approach briefing would help to reinforce awareness of this tricky airplane behavior.
Experience on the airplane certainly helps, as I did not see full control inputs anymore after those early years. That means that anyone who has fewer than, say, a few years on the airplane has to stay extra vigilant. And the pilot next to him/her as well.
And don’t think twice about going around.
For the mindset, it might help to always take along enough fuel for an - extra - go around (on top of the std 30 mins final reserve). That way going around becomes a bit more carefree.
An extra expense, for sure. But accidents or incidents are more expensive.
I once read a beautiful suggestion on PPRuNe; a bottle of wine each for pilots that made a go around, no questions asked. With compliments, from the MFO. FDM will take care of everything else.
Bottom line; even though the MD-11 is an airplane with certain peculiarities, it can be flown safely by experienced and professional crews.
But be careful landing it.
Last edited by Mariner; 26th Feb 2012 at 14:01.
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Mariner - thanks for a really interesting post.
Slightly off topic, but I have to respond to Vc10tail's comment "In my view, the DC-10 is one of the worst designed airplanes to ever come down the pike".
I thought it was a beautiful aircraft and a delight to fly. However, I may be biased as it was also the last large aircraft I ever flew after Laker went bust almost exactly 30 years ago.
Slightly off topic, but I have to respond to Vc10tail's comment "In my view, the DC-10 is one of the worst designed airplanes to ever come down the pike".
I thought it was a beautiful aircraft and a delight to fly. However, I may be biased as it was also the last large aircraft I ever flew after Laker went bust almost exactly 30 years ago.
Last edited by Old and Horrified; 26th Feb 2012 at 15:44.
Gretchenfrage;
Thanks for your input. The discussion I was hoping for and am now seeing was one between professional airline pilots, some of who may have flown the MD11 as I have not.
I am as interested in understanding this airplane as I do the Airbus. I don't wish to get into a push-and-pull regarding types either mainly because questions of complexity are different than questions of stability. The A330 airframe design doesn't have habits which require forgiving but its fbw & level of automation certainly does demand a very high level of understanding and therefore training, just, (as you say), in different areas. To the industry, "training" and even hiring, seem to be areas in which airline CEOs seem to think they can cheapen because "modern airplanes fly themselves", or some such variation on the theme. - another thread!
I have no point of view on the MD11...understanding is not a point of view, but I do have a point of view on the A330 and Airbus because I'd flown them for fifteen years until retirement. I'm very interested in the thoughts of those who have experience on the MD11 and for that reason I do appreciate your posts.
DOVES;
Mi piacere...grazi, (I wish I knew more!). I am hearing similarities with Mariner's post.
Mariner, many thanks for a superb, dispassionate summary. It helps understanding greatly, offering appropriate cautions while respecting the aircraft and the skill of those flying it.
In my reading (both private and here), I sense also that the CofG is a bit further aft than other transports. Coupled with the factors you have described regarding longitudinal inertia etc, that becomes another aspect to be respected.
You mention FDM...has the program helped in terms of addressing these issues, especially for those transitioning to the airplane?
Thanks for your input. The discussion I was hoping for and am now seeing was one between professional airline pilots, some of who may have flown the MD11 as I have not.
I am as interested in understanding this airplane as I do the Airbus. I don't wish to get into a push-and-pull regarding types either mainly because questions of complexity are different than questions of stability. The A330 airframe design doesn't have habits which require forgiving but its fbw & level of automation certainly does demand a very high level of understanding and therefore training, just, (as you say), in different areas. To the industry, "training" and even hiring, seem to be areas in which airline CEOs seem to think they can cheapen because "modern airplanes fly themselves", or some such variation on the theme. - another thread!
I have no point of view on the MD11...understanding is not a point of view, but I do have a point of view on the A330 and Airbus because I'd flown them for fifteen years until retirement. I'm very interested in the thoughts of those who have experience on the MD11 and for that reason I do appreciate your posts.
DOVES;
Mi piacere...grazi, (I wish I knew more!). I am hearing similarities with Mariner's post.
Mariner, many thanks for a superb, dispassionate summary. It helps understanding greatly, offering appropriate cautions while respecting the aircraft and the skill of those flying it.
In my reading (both private and here), I sense also that the CofG is a bit further aft than other transports. Coupled with the factors you have described regarding longitudinal inertia etc, that becomes another aspect to be respected.
You mention FDM...has the program helped in terms of addressing these issues, especially for those transitioning to the airplane?
Last edited by PJ2; 26th Feb 2012 at 17:28.
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PJ, thanks.
Having flown both, I remain quite philosophical.
The MD11 unveiled today's lack of pilot skills. As the industry needed so many jockeys, it showed that there's only a limited number of Topper Harleys, you can dig as deep as you want. The modern airliner needed to be more forgiving to adapt to such fact. The MD11 might just have been slightly over the tolerance.
The fbw Airbus unveiled today's lack of IT and aircraft operating system knowledge. Again, there's only a limited number of Greg Woszniakies, you can did as deep as you want. The modern airliner should therefore be less complex in abnormal situation handling. The Airbus might just be slightly over that tolerance.
Without wanting to judge, or fall into a A-B discussion or lobbyists trap, let me simply state, that being on the T7 now, I am relatively happy. This design is very forgiving on landings and has a more hands on approach on fbw.
(but please fix that damned spoiler!)
Having flown both, I remain quite philosophical.
The MD11 unveiled today's lack of pilot skills. As the industry needed so many jockeys, it showed that there's only a limited number of Topper Harleys, you can dig as deep as you want. The modern airliner needed to be more forgiving to adapt to such fact. The MD11 might just have been slightly over the tolerance.
The fbw Airbus unveiled today's lack of IT and aircraft operating system knowledge. Again, there's only a limited number of Greg Woszniakies, you can did as deep as you want. The modern airliner should therefore be less complex in abnormal situation handling. The Airbus might just be slightly over that tolerance.
Without wanting to judge, or fall into a A-B discussion or lobbyists trap, let me simply state, that being on the T7 now, I am relatively happy. This design is very forgiving on landings and has a more hands on approach on fbw.
(but please fix that damned spoiler!)
Gretchenfrage, yes, I remain on the philosophical side as well, happy in retirement and doing a little flight safety work on the side. Nor do I desire to lobby...I consider myself deeply fortunate just to have achieved a childhood dream. Sadly not many can say this and I am forever humbled.
As I watched our Navs being replaced with INS, then the first trials of Honeywell's "FMS" (on a B727) and the developments of the L1011 & B767 which initially was built with a panel for the oiler, I never felt that automation was "inevitable" as an operational solution to the problems of flight itself.
But in order to wring maximum mileage and carrying capability per kilo burnt and to reduce crew costs perhaps the "solution" was somewhat inevitable, but certainly not from a human point of view.
It is true that flight safety has been enhanced thereby but I would never believe anyone who may claim that safety was the prime objective in automated flight.
Not only raw flying skills but instrument scan, thinking skills and knowledge of the machine and of aerodynamics of high speed, high altitude flight have all atrophied to the point where fewer and fewer do not know how much they don't know. I've written at length elsewhere about this.
The T7 seems to be a very happy balance. My favourite was the L1011-500 but the A330 was a very fine airplane once one understood autoflight and that usually takes a year or two of hard work. Trouble is, if I may be permitted one small advertisement, the airplane works so well that once the bread-and-butter push-buttony thing is learnt it masks this need for deeper knowledge and some people who fly it get comfortable, then lazy.
As I watched our Navs being replaced with INS, then the first trials of Honeywell's "FMS" (on a B727) and the developments of the L1011 & B767 which initially was built with a panel for the oiler, I never felt that automation was "inevitable" as an operational solution to the problems of flight itself.
But in order to wring maximum mileage and carrying capability per kilo burnt and to reduce crew costs perhaps the "solution" was somewhat inevitable, but certainly not from a human point of view.
It is true that flight safety has been enhanced thereby but I would never believe anyone who may claim that safety was the prime objective in automated flight.
Not only raw flying skills but instrument scan, thinking skills and knowledge of the machine and of aerodynamics of high speed, high altitude flight have all atrophied to the point where fewer and fewer do not know how much they don't know. I've written at length elsewhere about this.
The T7 seems to be a very happy balance. My favourite was the L1011-500 but the A330 was a very fine airplane once one understood autoflight and that usually takes a year or two of hard work. Trouble is, if I may be permitted one small advertisement, the airplane works so well that once the bread-and-butter push-buttony thing is learnt it masks this need for deeper knowledge and some people who fly it get comfortable, then lazy.
MD - Mariner's observations.
Thats a pretty good summation of the MD, mariner; it is an aircraft that requires proficiency.
The original idea to reduce the stabiliser was reasonable given the arm change that occurred with the fuselage extension. Unfortunately, the aircraft also has other "minor changes" that do change the flow conditions of the stabiliser and elevators. (if you want to know what, PM me and I will provide some reference material to indicate what is occurring).
I'm not rated on the MD, but I have done HQ on it, in relation to accident and incident investigation, and a couple of issues were notable. 1, the simulator aero model is very much constrained to normal operational envelope, ie it is anywhere from inconsistent to wildly erroneous as you proceed outside of the normal envelope (these including areas that the operators train within); 2, the aircraft is prone to PIO particularly in high altitude operations without LSAS, but also in the flare; 3, is susceptible to flow related damage when operated outside of the buffet boundary. The machine meets the requirements of the Part, but is arguably on the higher side of nice on the C-H HQ scale. The stick force gradient is normal. (I am testing one non part 25 aircraft at present that has two distinct ranges of static instability, and it was considered by the powers that be to be suitable for fairly low time fodder to fly... it is interesting, but definitely demands care and respect). The Scud has a repeated failure mode of the wing with hard landings, which certainly suggests it be good practice to avoid operations occasioning high isolated wheel ground impacts. Caveat: my experience with the aircraft is a number of years ago, and there have been some beneficial and overdue changes incorporated to the FMGS and other systems.
With all of that, it still is a neat aircraft, and handles nicely enough, but all round, with the high approach speeds that are characteristic of the fleets operation as a freighter coupled with a very simple flap system (nice though), on dark nights, tired crew etc, it is a handful.
Personally, I think that the addition of a HUD is a nice secondary solution to the aircraft's tiger-by-the-tail reputation. The HUD gives a good indication of any increasing sink rate on short final, (CLK dynasty bingle) and also an indication of the initial effectiveness of flare input WRT flight path.
The stability issue and the approach speed are eminently possible to modify, but I doubt that any current user wants to pay for the necessary STC. (The plane is ripe for a reduction in approach speed in the order of 15% with simple modifications, which would also alter the trim condition favourably).
Love the DC/MD's sunroom, great place to enjoy the view from. The systems and automatics otherwise were years ahead of the competition. FWIW, while I really like the MD, I think that the Capt's that give away sectors to low time new crew need to be given medals for valor.
Thats a pretty good summation of the MD, mariner; it is an aircraft that requires proficiency.
The original idea to reduce the stabiliser was reasonable given the arm change that occurred with the fuselage extension. Unfortunately, the aircraft also has other "minor changes" that do change the flow conditions of the stabiliser and elevators. (if you want to know what, PM me and I will provide some reference material to indicate what is occurring).
I'm not rated on the MD, but I have done HQ on it, in relation to accident and incident investigation, and a couple of issues were notable. 1, the simulator aero model is very much constrained to normal operational envelope, ie it is anywhere from inconsistent to wildly erroneous as you proceed outside of the normal envelope (these including areas that the operators train within); 2, the aircraft is prone to PIO particularly in high altitude operations without LSAS, but also in the flare; 3, is susceptible to flow related damage when operated outside of the buffet boundary. The machine meets the requirements of the Part, but is arguably on the higher side of nice on the C-H HQ scale. The stick force gradient is normal. (I am testing one non part 25 aircraft at present that has two distinct ranges of static instability, and it was considered by the powers that be to be suitable for fairly low time fodder to fly... it is interesting, but definitely demands care and respect). The Scud has a repeated failure mode of the wing with hard landings, which certainly suggests it be good practice to avoid operations occasioning high isolated wheel ground impacts. Caveat: my experience with the aircraft is a number of years ago, and there have been some beneficial and overdue changes incorporated to the FMGS and other systems.
With all of that, it still is a neat aircraft, and handles nicely enough, but all round, with the high approach speeds that are characteristic of the fleets operation as a freighter coupled with a very simple flap system (nice though), on dark nights, tired crew etc, it is a handful.
Personally, I think that the addition of a HUD is a nice secondary solution to the aircraft's tiger-by-the-tail reputation. The HUD gives a good indication of any increasing sink rate on short final, (CLK dynasty bingle) and also an indication of the initial effectiveness of flare input WRT flight path.
The stability issue and the approach speed are eminently possible to modify, but I doubt that any current user wants to pay for the necessary STC. (The plane is ripe for a reduction in approach speed in the order of 15% with simple modifications, which would also alter the trim condition favourably).
Love the DC/MD's sunroom, great place to enjoy the view from. The systems and automatics otherwise were years ahead of the competition. FWIW, while I really like the MD, I think that the Capt's that give away sectors to low time new crew need to be given medals for valor.
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Originally Posted by Mariner's excellent summary
But the pitch rate will continue after touchdown due to the longitudinal inertia, added by the pitch up tendency caused by the spoilers. So a good push is needed to avoid a tail strike.
Being a bit of a systems geek, this bit about the spoilers caught my attention.
Seems to me that the new B748 was found to have a similar tendency during early test flying. The solution was to add a bit of a time delay to the outboard spoilers activation.
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MacD?
Machinbird
In a long discussion re: Narita, the main spar fractures came up. One cannot help but remember that the design and manufacture of this a/c (MD-11) was the effort of a company that designed another heavy a/c made to plant on the carrier deck.
As a Phantom driver, I'd be interested in your take on the placement of the Main Landing Gear struts directly under and to the Main Wing Spars. The focal energy on the wing is apparent in watching that tragic vid at Narita. Likewise, the Nose Gear remains (undamaged?) after the intense Nose Plant on the final hop.
Given that this a/c lands heavy and with Pitch issues, would some attention paid to sacrificial structures have been indicated in its design/service/survivability?
fdr: just read your note re: hard landings. What do you think of the gearMate?
In a long discussion re: Narita, the main spar fractures came up. One cannot help but remember that the design and manufacture of this a/c (MD-11) was the effort of a company that designed another heavy a/c made to plant on the carrier deck.
As a Phantom driver, I'd be interested in your take on the placement of the Main Landing Gear struts directly under and to the Main Wing Spars. The focal energy on the wing is apparent in watching that tragic vid at Narita. Likewise, the Nose Gear remains (undamaged?) after the intense Nose Plant on the final hop.
Given that this a/c lands heavy and with Pitch issues, would some attention paid to sacrificial structures have been indicated in its design/service/survivability?
fdr: just read your note re: hard landings. What do you think of the gearMate?
Last edited by Lyman; 27th Feb 2012 at 14:32.
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Lyman, you are confusing the right hand and the left hand. The Phantom was designed long before in St Louis by McDonnell only. The MD-11 in Long Beach 20+ years later using a lot of Douglas DC-10 technology.
In any case, substantive modifications to the aircraft in that part of the airframe are likely to cost really big $$$ and cannot be economically justified.
The MD-11 could probably also use a "bounce" warning system with a verbal annunciation of the condition. If it is that hard to tell (in time) that the aircraft has transitioned back to airborne after a firm landing, then something should warn the guys flying. (More systems geek thoughts.
)
In any case, substantive modifications to the aircraft in that part of the airframe are likely to cost really big $$$ and cannot be economically justified.
The MD-11 could probably also use a "bounce" warning system with a verbal annunciation of the condition. If it is that hard to tell (in time) that the aircraft has transitioned back to airborne after a firm landing, then something should warn the guys flying. (More systems geek thoughts.
)
Last edited by Machinbird; 28th Feb 2012 at 02:00. Reason: making a confusing comma into a period.
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The key to this accident is in the chart on the last page. The MD-11 does not have anything particularly unique about its handling characteristics. All the stuff about size of the tail, etc., does not hold up when actually analyzed. The "fear factor" has a greater impact on how pilots fly it than anything else.
Prof2MDA:
Re, "All the stuff about size of the tail, etc., does not hold up when actually analyzed. The "fear factor" has a greater impact on how pilots fly it than anything else. "
Who is doing the aeronautical work regarding analysis of the tail?
And speaking of not holding up, where is "fear factor" in the report?
In re the "size of the tail", there are some pretty clear indications from experienced and knowledgeable aviators who, we see, have lots of time on the aircraft and who are, in my view, qualified to make the statements they've made.
Comments regarding the size of the horizontal stabilizer have also been made in private communications.
On the other hand, nothing has been mentioned regarding "fear factor" but instead what has been mentioned is the aircraft's clear demand for competency and training. In this, there is nothing new even as standards are lower today, with increasinly visible results.
Re, "All the stuff about size of the tail, etc., does not hold up when actually analyzed. The "fear factor" has a greater impact on how pilots fly it than anything else. "
Who is doing the aeronautical work regarding analysis of the tail?
And speaking of not holding up, where is "fear factor" in the report?
In re the "size of the tail", there are some pretty clear indications from experienced and knowledgeable aviators who, we see, have lots of time on the aircraft and who are, in my view, qualified to make the statements they've made.
Comments regarding the size of the horizontal stabilizer have also been made in private communications.
On the other hand, nothing has been mentioned regarding "fear factor" but instead what has been mentioned is the aircraft's clear demand for competency and training. In this, there is nothing new even as standards are lower today, with increasinly visible results.
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Because of the height of the centre engine on the MD11 (and DC10), the application of reverse thrust is bound to pull the tail down resulting in a nose up tendency. Seems to me that reverse should NOT be used on the centre engine until some time after touchdown, if at all. Just my 2 cents worth.
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the wings snapped off
prof2MDA
I agree, the energy was enormous, but you misunderstand. This a/c DID survive the last flop on the deck. But the wings did not. The MLG survived, but the wings snapped.
In BA038, the 777 had a push through and bellied to a stop. If, at Narita, the gear had failed, the results may have been similar, and survivable. Machinbird, where do I advocate an AD on gear structure? The 777 RMLG folded back, unfortunately entering the cabin and maiming a passenger, but the wings stayed on, the tanks maintained integrity, and what fuel was left (little) did not ignite. Narita was a firestorm from the initial failure of the spar on.
You conclude the gear architecture was not similar in design. How's that? The DC-10 was built post Phantom also, by the same company that had concluded that hard mounting the struts to the spars was survivable. Clearly, in Narita, they were not. Even if the design was inked by different teams, the fact remains, the Gear did not fail, and I conclude that if it had, the crash was survivable.
I agree, the energy was enormous, but you misunderstand. This a/c DID survive the last flop on the deck. But the wings did not. The MLG survived, but the wings snapped.
In BA038, the 777 had a push through and bellied to a stop. If, at Narita, the gear had failed, the results may have been similar, and survivable. Machinbird, where do I advocate an AD on gear structure? The 777 RMLG folded back, unfortunately entering the cabin and maiming a passenger, but the wings stayed on, the tanks maintained integrity, and what fuel was left (little) did not ignite. Narita was a firestorm from the initial failure of the spar on.
You conclude the gear architecture was not similar in design. How's that? The DC-10 was built post Phantom also, by the same company that had concluded that hard mounting the struts to the spars was survivable. Clearly, in Narita, they were not. Even if the design was inked by different teams, the fact remains, the Gear did not fail, and I conclude that if it had, the crash was survivable.
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PJ2 - the work was done by all the groups involved in the various investigations, which included very high time MD-11 pilots as well as engineers from a variety of entities serving as "watch-dogs", if you will. While it is true that many pilots believe certain things, that does not make them true. Many pilots also believe provably false "theories" of lift.
The issues that have been raised are not new, and have been raised and investigated many times now. If they were true they would have been part of one of the accident reports. I raised the "fear" aspect because ANY airplane will behave differently if the pilots are even slightly nervous flying it and it would be enough to explain the accident rate, particularly as the rate is still low enough to be within statistical random distribution.
Lyman - while it is true that the 777 gear folds first, it is also true that 777 gear will collapse at a lot lower amount of force than it takes to break an MD-11 wing (roughly double), so, while you can get to a catastrophic accident in the extreme case, how many times are you averting a lesser (and possibly fatal) accident in the meantime? It is not such a simple thing.
The issues that have been raised are not new, and have been raised and investigated many times now. If they were true they would have been part of one of the accident reports. I raised the "fear" aspect because ANY airplane will behave differently if the pilots are even slightly nervous flying it and it would be enough to explain the accident rate, particularly as the rate is still low enough to be within statistical random distribution.
Lyman - while it is true that the 777 gear folds first, it is also true that 777 gear will collapse at a lot lower amount of force than it takes to break an MD-11 wing (roughly double), so, while you can get to a catastrophic accident in the extreme case, how many times are you averting a lesser (and possibly fatal) accident in the meantime? It is not such a simple thing.