Moderators: richierich, ua900, PanAm_DC10, hOMSaR
hitower3 wrote:I always wondered about the rationale behind some common type ratings. While I can understand the common rating for Boeing's 757 and 767 (the former's flight deck was even adjusted to match the view you get from the latter's), there are also examples of common type ratings I find doubtful: The MD11 for ex. shared the type rating with the DC-10, while there are significant differences in "user interface" (2 vs. 3 crew, CRT displays, etc.) and flight characteristics (approach speed, control authority, center of gravity).
Just my 0,02€...
Hendric
hitower3 wrote:I always wondered about the rationale behind some common type ratings. While I can understand the common rating for Boeing's 757 and 767 (the former's flight deck was even adjusted to match the view you get from the latter's), there are also examples of common type ratings I find doubtful: The MD11 for ex. shared the type rating with the DC-10, while there are significant differences in "user interface" (2 vs. 3 crew, CRT displays, etc.) and flight characteristics (approach speed, control authority, center of gravity).
Just my 0,02€...
Hendric
747classic wrote:The MD11 and MD10 can be operated with a common type rating (Fedex)), despite the very different aircraft handling (especially during landing), caused by the reduced sized horizontal stabilizer of the MD11.
IMHO a wrong decision of the FAA, contributing to several incidents/accidents, caused by the pitch unstability of the MD11(F) and main landing gear design issues of both the MD11 and DC(MD)10.
MD 11 (2 man) and DC10 (3 man) have a different type rating.
mmo wrote:... However the 400 flies very differently than the Classics. Thus the different type rating for the 400 and the same reason why the 400 and the 8 share the same type rating.
BravoOne wrote:Not aware of any strut issue causing an MD11 accident in and of themselves?
BartSimpson wrote:]mmo wrote:... However the 400 flies very differently than the Classics. Thus the different type rating for the 400 and the same reason why the 400 and the 8 share the same type rating.
That's interesting. Did the FAA have their own pilots who flew them and reported on the flight characteristics and thus decided to request different ratings or how has it done technically?
mmo wrote:BartSimpson wrote:]mmo wrote:... However the 400 flies very differently than the Classics. Thus the different type rating for the 400 and the same reason why the 400 and the 8 share the same type rating.
That's interesting. Did the FAA have their own pilots who flew them and reported on the flight characteristics and thus decided to request different ratings or how has it done technically?
Not sure just what pair you are talking about, but the 400 was flown by the FAA before it was certified and the FAA pilots certainly had their input to the certification branch. The 748 is partially FBW, so the flight characteristics can be tweaked to be exactly like the 400.
I was at NW at the time and involved with the launch. The FAA's big worry was going from a 3 to 2 man cockpit and the conversion from Steam gauge to Glass.
zeke wrote:It all depends on the regulator, the 777/787, A330/A350 are common type ratings under EASA however they are not under the FAA.
I suspect the 797 will have 787 style avionics suite which will make it more likely to have a common type with the 787. The 737 has too much history (older generation 737s) there to be a common type with newer aircraft. A new 2030 737 replacement will be more likely to have common type.
With larger fleets its is more practical to just have pools of pilots flying one or two types. The real saving is the reduced training required from one to the other like Airbus pioneered with the cross crew qualification concept.
Siren wrote:BravoOne wrote:Not aware of any strut issue causing an MD11 accident in and of themselves?
Put an MD-11 down on the runway too hard, and the MLG will cause failure of the wing spar, which is why the MD-11s have a tendency to turn over onto their backs and explode. Yes, I'm using hyperbole here, but, this fits into the category of 'design flaw'. If designed properly, the landing gear attachment points should fail, and cause failure of the landing gear if the structural limits are exceeded. This isn't the case with the MD-11 - the landing gear strut stays firmly attached, and the entire assembly gets punched through the wing spar, causing failure of the wing.
There have been 4 hull loss accidents due to this behavior (FedEx 14, FedEx 80, Mandarin 642, Centurion 425), and several more landing accidents thanks to the lack of pitch authority from the undersized stabilizer (one additional hull loss that I'm aware of, LH Cargo 8460)...
On the last point: the MD-11s are also difficult to handle at slow speeds. I've heard anecdotally that air traffic controllers hate to deal with the MD-11s due to their high minimum approach speeds. The handling of the airframe is completely different than the DC-10, which is much easier to handle at slow speeds. A common type rating was a mistake, in my view...
So, to the original question: You can take 'common' type ratings pretty far - even if there's little commonality. A good example of the reverse of the MD-11/MD-10 type rating snafu is the common type rating applied to the 737 Classic vs the NG. You can have full analogue flight decks on the Classics - glass was an option on them that many airlines did not take. Yet, they granted the 737s a common type rating. Look at a steam gauge -300 versus a -700, and you'll see what I mean. The planes may handle similarly, but the flight decks and crew interfaces are completely different....
BravoOne wrote:747classic wrote:The MD11 and MD10 can be operated with a common type rating (Fedex)), despite the very different aircraft handling (especially during landing), caused by the reduced sized horizontal stabilizer of the MD11.
IMHO a wrong decision of the FAA, contributing to several incidents/accidents, caused by the pitch unstability of the MD11(F) and main landing gear design issues of both the MD11 and DC(MD)10.
Expand a little if you would on the differences between the DC/MD-10 landing gear and the MD11 landing gear. I assume you may be referring to the dual chamber strut ont he MD11 vs. the older single chamber on the early DC10-30 designs, although I think later sn DC10-30's may have shared the dual chamber design. Not aware of any strut issue causing an MD11 accident in and of themselves?
BravoOne wrote:It does make we wonder when you talk about low speed handling and then go on to take issue with the high approach speeds? Which is it?
Siren wrote:BravoOne wrote:It does make we wonder when you talk about low speed handling and then go on to take issue with the high approach speeds? Which is it?
747classic gave the perfect technical explanation of my main contention with the MD-11 design...
And to answer your question, "which is it?", it's both. High approach speeds exist because the aircraft's low speed handling characteristics are such that the aircraft will stall out if you slow it further. This is still poor "low speed handling", despite high relative speeds to other airliners.
BravoOne wrote:Stall? A little bit of drama me thinks. FedEx fly many thousands of hours every month in he MD11 without screw ups. When they do, they are dramatic for sure but to knowledge no authority has blamed the airplane for the accidents themselves. I do agree that you need to bring you best game to town when you fly it but then that's true for any number of airplanes.
How much experience do you have flying the DC10 or MD11, or is your information mostly just from websites like this one?
hitower3 wrote:I always wondered about the rationale behind some common type ratings. While I can understand the common rating for Boeing's 757 and 767 (the former's flight deck was even adjusted to match the view you get from the latter's), there are also examples of common type ratings I find doubtful: The MD11 for ex. shared the type rating with the DC-10, while there are significant differences in "user interface" (2 vs. 3 crew, CRT displays, etc.) and flight characteristics (approach speed, control authority, center of gravity).
Just my 0,02€...
Hendric
Siren wrote:BravoOne wrote:Not aware of any strut issue causing an MD11 accident in and of themselves?
Put an MD-11 down on the runway too hard, and the MLG will cause failure of the wing spar, which is why the MD-11s have a tendency to turn over onto their backs and explode. Yes, I'm using hyperbole here, but, this fits into the category of 'design flaw'. If designed properly, the landing gear attachment points should fail, and cause failure of the landing gear if the structural limits are exceeded. This isn't the case with the MD-11 - the landing gear strut stays firmly attached, and the entire assembly gets punched through the wing spar, causing failure of the wing.
There have been 4 hull loss accidents due to this behavior (FedEx 14, FedEx 80, Mandarin 642, Centurion 425), and several more landing accidents thanks to the lack of pitch authority from the undersized stabilizer (one additional hull loss that I'm aware of, LH Cargo 8460)...
On the last point: the MD-11s are also difficult to handle at slow speeds. I've heard anecdotally that air traffic controllers hate to deal with the MD-11s due to their high minimum approach speeds. The handling of the airframe is completely different than the DC-10, which is much easier to handle at slow speeds. A common type rating was a mistake, in my view...
So, to the original question: You can take 'common' type ratings pretty far - even if there's little commonality. A good example of the reverse of the MD-11/MD-10 type rating snafu is the common type rating applied to the 737 Classic vs the NG. You can have full analogue flight decks on the Classics - glass was an option on them that many airlines did not take. Yet, they granted the 737s a common type rating. Look at a steam gauge -300 versus a -700, and you'll see what I mean. The planes may handle similarly, but the flight decks and crew interfaces are completely different....
CosmicCruiser wrote:
Actually it was not just a hard landing that would cause main gear failure; it was a hard landing with a side load on the gear. We were grilled in the sim when doing x-wind landings to 0 out ALL drift. I can say of the crashes I know off personally it was always a side load and not necessarily the first touchdown but the subsequent bounce with a side load. If you research it there are at least 2 MD-10s that had the same gear failure on landing with a side load. As far as approach speeds yes it was high but not such a big deal unless you were close to max ldg wgt. At max Vapp was 168. When light it could be close to 140. I never considered it difficult at all, you just flew the speed and that was it regardless of it being a -11 or MD-10. The -11 was certainly more sensitive on the controls than the MD-10. I much more preferred the -11 than the MD-10 especially in landing but like I said I flew it 99% of the time. The worst situation I think is one where a pilot flies the MD-10 99% of the time then hops in an -11.
BravoOne wrote:This maybe a dumb question but doesn't the MD10, fly like the DC10, albeit with the two pilot flight deck?
I have worked with a few FedEx pilots and there seems to be mixed opinions of this rating issue?
BravoOne wrote:From the NTSB Accident report. "Captains over-control of the airplane during the landing and his failure to go-around fro a de-stabilized flare."
This was the cause of the accident, and the wing spar failure occurred when the load exceeded the original Part 25 design criteria. As someone once said, the airplane has a glass chin. and does not tolerate less than ideal airmanship.
Flying with the AT engaged, and clicking them off at 100 AGL is just begging for trouble IMO
BravoOne wrote:This maybe a dumb question but doesn't the MD10, fly like the DC10, albeit with the two pilot flight deck?
I have worked with a few FedEx pilots and there seems to be mixed opinions of this rating issue?
BravoOne wrote:I know the difference between the airframes, just wanted to know about the different handling qualities. The 757/767 share a common type and while Boeing has done a lot to mitigate the differences there is no way a 400K 767-300ER flies the same as 245K 757-200.
As I mentioned earlier there seems to be a significant difference of opinion between the FedEx pilot regarding the significance of these handling qualities?
You say "Several" when describing the number of MD11;s converted. I thought it was a significant number of the existing DC10 fleet?
BravoOne wrote:As I mentioned earlier there seems to be a significant difference of opinion between the FedEx pilot regarding the significance of these handling qualities?
You say "Several" when describing the number of MD11;s converted. I thought it was a significant number of the existing DC10 fleet?
CosmicCruiser wrote:BravoOne wrote:From the NTSB Accident report. "Captains over-control of the airplane during the landing and his failure to go-around fro a de-stabilized flare."
This was the cause of the accident, and the wing spar failure occurred when the load exceeded the original Part 25 design criteria. As someone once said, the airplane has a glass chin. and does not tolerate less than ideal airmanship.
Flying with the AT engaged, and clicking them off at 100 AGL is just begging for trouble IMO
I don't know what accident you're referring to so I'll just say of the 2 I know, they hit hard for 2 different reasons and came down with a slight yaw. The next contact was gear failure and as I also said our trg stressed very heavily to have no drift in a x-wind ldg as well as changes to a bounced ldg being a mandatory go around.
I never said I would click off the A/T at 100' but any way I had better landings in the MD-10 without A/T because I retarded them slower and got the nose up before idle. And as far as your comment, we actually were told because of the dependance on automation we should select low work load flights and fly totally manual landings as often as we could. I had no problem with the MD-11 A/T.
CosmicCruiser wrote:BravoOne wrote:As I mentioned earlier there seems to be a significant difference of opinion between the FedEx pilot regarding the significance of these handling qualities?
You say "Several" when describing the number of MD11;s converted. I thought it was a significant number of the existing DC10 fleet?
Dc-10s were converted not MD-11s.
I said the handling was different being that the MD-11 was much more sensitive. Like I said I think the worst case scenario would be the guy that flew the MD-10 mostly and rarely saw an MD-11. I actually flew left and right seat in the DC-10 and thought it was great but once I moved to the MD-11 it felt so much better that I had to work at a good ldg in the MD-10.
BravoOne wrote:CosmicCruiser wrote:BravoOne wrote:From the NTSB Accident report. "Captains over-control of the airplane during the landing and his failure to go-around fro a de-stabilized flare."
This was the cause of the accident, and the wing spar failure occurred when the load exceeded the original Part 25 design criteria. As someone once said, the airplane has a glass chin. and does not tolerate less than ideal airmanship.
Flying with the AT engaged, and clicking them off at 100 AGL is just begging for trouble IMO
I don't know what accident you're referring to so I'll just say of the 2 I know, they hit hard for 2 different reasons and came down with a slight yaw. The next contact was gear failure and as I also said our trg stressed very heavily to have no drift in a x-wind ldg as well as changes to a bounced ldg being a mandatory go around.
I never said I would click off the A/T at 100' but any way I had better landings in the MD-10 without A/T because I retarded them slower and got the nose up before idle. And as far as your comment, we actually were told because of the dependance on automation we should select low work load flights and fly totally manual landings as often as we could. I had no problem with the MD-11 A/T.
That report was from the EWR accident. The only NRT report I have see was by the Japanese which was very well don IMO. I did accuse you of anything so get over that, please.