tsugambler
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Technical Differences Between L-1011 And DC-10

Tue Aug 31, 2010 5:58 pm

I've heard many people assert that the L-1011 was a more technically advanced aircraft than the DC-10; however, they never seem to state what exactly the technical differences are. In what ways is the L-1011 more advanced than the DC-10? And in what ways (if any) is the DC-10 more advanced than the L-1011? (I'm not necessarily asking which one everyone likes more, although you can certainly add that if you wish... as for me, I've always loved the DC-10, despite its reputed flaws.) And..... go!
 
PGNCS
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RE: Technical Differences Between L-1011 And DC-10

Tue Aug 31, 2010 6:05 pm

This is way too big a topic to go into here. You need a complete manual set of each to even start. I have the manuals (though I never flew the DC-10,) but this is a gigantically general question and books could be written on it. Whatever answers you get, they will be confined to high points like L-1011 hydraulic redundancy, DLC, etc., but will not ultimately be representative of the whole picture of the vastly different design decisions made at the macro-level and at the individual component and part level.
 
Daysleeper
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RE: Technical Differences Between L-1011 And DC-10

Tue Aug 31, 2010 6:17 pm

I don't know a great deal about the L1011 TBH, but one differance which sticks out for whatever reason was the fact it used an S duct for engine 2 where as the D10 had it mounted up high. I know this caused a few performance issues, in that the L1011 had to be rolling at a fair old whack before they could apply full power to the number 2, but it also made maintenance significantly easier with the engine being much lower.
 
PGNCS
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RE: Technical Differences Between L-1011 And DC-10

Tue Aug 31, 2010 6:29 pm

Quoting Daysleeper (Reply 2):
I know this caused a few performance issues, in that the L1011 had to be rolling at a fair old whack before they could apply full power to the number 2, but it also made maintenance significantly easier with the engine being much lower.

Not really. That was true on a 727 in a significant crosswind, however.
 
tsugambler
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RE: Technical Differences Between L-1011 And DC-10

Tue Aug 31, 2010 6:45 pm

General high points are just fine for me... I'm not sure I'd have enough technical knowledge to understand the really detailed nitty-gritty. Things like "hydraulic redundancy" are exactly what I'm looking for, however. Keep 'em coming!
 
tymnbalewne
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RE: Technical Differences Between L-1011 And DC-10

Tue Aug 31, 2010 6:54 pm

You'll notice that the L-1011 has two beacons on top vs, the DC-10's one. I was told that Lockheed did this so that the aircraft couldn't be grounded should a beacon go out of service at an airport without appropriate maintenance.
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474218
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RE: Technical Differences Between L-1011 And DC-10

Tue Aug 31, 2010 7:29 pm

The technical difference between the DC-10 and the L-1011 are easy to explain:

The DC-10 was a follow on project after the DC-8 and DC-9. It borrowed heavily on both previous projects to save money and cut development time.

The L-1011 design was a clean sheet of paper, new systems were built into design from the very beginning, Cat III Auto Land, Flying Stabilizer and Direct Lift Control are three.
 
B777LRF
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RE: Technical Differences Between L-1011 And DC-10

Tue Aug 31, 2010 7:45 pm

It's a bit like comparing the differences between a Cadillac and a Mercedes-Benz. Technically speaking, they're both luxury automobiles, but the design process, engineering, technology, innovation and production standards of the two products are widely different.

Agreed, there's also the brand snobbery to consider in the above example, and that's not something worth much in the world of airline bean counters - but if it had been left to the guys and gals on the coalface to choose between either an Elleteneleven and a Diesel-Ten, the legacy of the two aircraft might well have been reversed.*

Alas, the -10 will go down in history as the commercial winner of the wide-bodied trimotor contest and the TriStar as Lockheeds swan song as far as commercial aircraft goes, despite it being the pilots aircraft par excellence and, in its own way, the technologically superior product.**

* At this point, there's bound to be someone out there sharpening keyboard in preparation of launching a tirade on early L-1011 mishaps. True, it had at least one crash which captured the imagination of tabloid editors and conspiracy theorists alike, and that mishap did tarnish the L-1011's reputation amongst the unwashed public. But the -10 had its share of accidents too, but somehow managed to come out the other end with less bad publicity. Lockheed had great engineers, but were a lot less accomplished in the art of media spin. And history showed it was the -10 which had a design flaw, not the TriStar.

** Initial RB-211 donks excluded - another example of how pioneering technology, first ridiculed, eventually turned out rather first class.
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Tristarsteve
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RE: Technical Differences Between L-1011 And DC-10

Tue Aug 31, 2010 8:45 pm

Quoting PGNCS (Reply 3):
Quoting Daysleeper (Reply 2):
I know this caused a few performance issues, in that the L1011 had to be rolling at a fair old whack before they could apply full power to the number 2, but it also made maintenance significantly easier with the engine being much lower.

Not really. That was true on a 727 in a significant crosswind, however.

The Tristar S duct was designed for the 42000 lb thrust RB211-22B. and it worked OK. You could get take off thrust at a standstill.
But the -524B which came along 3 years later had over 50000 lb thrust. The S duct, and in fact the engine, dimensions were unchanged. At take off, over 20 pc more air tried to go down the same duct. It didn't work until the aircraft was rolling into about a 40kt wind.

This caused us maintenance guys a problem. We could not run up a nbr 2 engine to take off. Lockheed put loads of graphs and tables in the AMM so you could work out if you would get take off thrust, but we had an engine shop that replaced engine modules, but had no test bed. So we carried out the test bed run on the aircraft. ( If all went well I could do all the tests 1 through 15 in about 45 minutes.) With a rebuilt engine, we could not do this in nbr 2 position, which occasionally led to multiple engine changes if we did not have a ready tested engine in the hangar.
 
Max Q
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RE: Technical Differences Between L-1011 And DC-10

Wed Sep 01, 2010 6:04 am

The L1011 never had a design caused accident.



Not many Aircraft can claim that. The Eastern crash in the Everglades was, sadly caused by crew error.



No one was actively monitoring the Aircraft's altitude while the rest of the Crew dealt with a minor technical issue and, as a result they allowed it to descend into the ground without intervention.
The best contribution to safety is a competent Pilot.
 
dw747400
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RE: Technical Differences Between L-1011 And DC-10

Wed Sep 01, 2010 7:22 am

One minor note I've heard:

Placing the L1011 engine in the fuselage allowed for a larger, more effective rudder than on the DC-10. This allowed the wing engines to be placed further outboard, which improves wing-bending relief and reduces structural weight.
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Jetlagged
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RE: Technical Differences Between L-1011 And DC-10

Wed Sep 01, 2010 12:24 pm

Quoting Max Q (Reply 9):
The L1011 never had a design caused accident.

In most accidents the design can contribute to the cause. Accidents where the design causes the accident comparatively are rare. The infamous Chicago and Paris DC-10 accidents were not caused by design problems, for example, but poor design contributed to the result.
The glass isn't half empty, or half full, it's twice as big as it needs to be.
 
AirframeAS
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RE: Technical Differences Between L-1011 And DC-10

Wed Sep 01, 2010 10:29 pm

Quoting tsugambler (Thread starter):
I've heard many people assert that the L-1011 was a more technically advanced aircraft than the DC-10

If someone were to tell me that, my rebuttal would be "If it (L-1011) was more technically advanced, then why did the DC-10 outsell the L-1011?"
A Safe Flight Begins With Quality Maintenance On The Ground.
 
tdscanuck
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RE: Technical Differences Between L-1011 And DC-10

Wed Sep 01, 2010 11:22 pm

Quoting AirframeAS (Reply 12):
"If it (L-1011) was more technically advanced, then why did the DC-10 outsell the L-1011?"

The Bugatti Veyron is unquestionably more technically advanced than the Volkswagon Beetle...guess which one sold more.

Tom.
 
Max Q
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RE: Technical Differences Between L-1011 And DC-10

Wed Sep 01, 2010 11:27 pm

Quoting jetlagged (Reply 11):

In most accidents the design can contribute to the cause. Accidents where the design causes the accident comparatively are rare. The infamous Chicago and Paris DC-10 accidents were not caused by design problems, for example, but poor design contributed to the result.

There are clear cases of accidents caused by bad design. The DC10 cargo door design was one, the failure of this door was a direct cause in the loss of control and fatal crash of the THY Aircraft in Paris.



The L1011 never had a design caused accident.

Quoting AirframeAS (Reply 12):

If someone were to tell me that, my rebuttal would be "If it (L-1011) was more technically advanced, then why did the DC-10 outsell the L-1011?"

There is no issue for rebuttal, the L1011 was more technically advanced than the DC10 without doubt.



But technology doesn't always sell.


Simple as that.
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Viscount724
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RE: Technical Differences Between L-1011 And DC-10

Thu Sep 02, 2010 12:19 am

Quoting AirframeAS (Reply 12):
If it (L-1011) was more technically advanced, then why did the DC-10 outsell the L-1011?

There was never an L-1011 with the same combination of payload and range as the DC-10-30. The L-1011-500 wasn't competitive with the DC-10-30 due to the shortened fuselage and resulting reduced seating and cargo capacity. The DC-10 was also available from the factory in combi and convertible models with main-deck cargo door which the L-1011 never was.
 
tdscanuck
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RE: Technical Differences Between L-1011 And DC-10

Thu Sep 02, 2010 12:21 am

Quoting Max Q (Reply 14):
There are clear cases of accidents caused by bad design. The DC10 cargo door design was one

In that case, design was a contributing factor but not the only one. *If* you latched the cargo door properly, it worked just fine. The design problem was that you could get the door into a state (by using unreasonable force on the mechanism) where it appeared to be locked but wasn't. This is, obviously, a giant design flaw but it wouldn't have caused an accident if people hadn't tried to strong-arm the latching mechanism instead of checking why it was so !#%!@% hard to close.

Tom.
 
474218
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RE: Technical Differences Between L-1011 And DC-10

Thu Sep 02, 2010 12:37 am

Quoting AirframeAS (Reply 12):
If someone were to tell me that, my rebuttal would be "If it (L-1011) was more technically advanced, then why did the DC-10 outsell the L-1011?"



Back in the 1970 there was a saying that was going around: The perfect airliner would be:

1. Designed by Lockheed

2. Built by Boeing

3. Sold my Douglas

The truth is that Douglas had a known sales team, they had loyal customers and they had a product that could do the job.

Lockheed had left a bad taste in many airlines mouth with the Electra. Not because of the early crashes, as Lockheed paid to fix all the Electra's. But because when they stopped producing them they stopped fully supporting them.

So even though Lockheed had a superior product it was had to convince some airlines that this time things would be different.
 
tsugambler
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RE: Technical Differences Between L-1011 And DC-10

Thu Sep 02, 2010 3:15 am

Re: 474218

That's interesting, I never knew that Lockheed had any sort of negative reputation re: product support. Of course, it wasn't until I started reading the forums here that I had any inkling that James McDonnell might have been in any way responsible for the declining fortunes of Douglas Aircraft in the civilian market. (And of course, I'm sure there are arguments to be had about that, too!   )
 
AirframeAS
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RE: Technical Differences Between L-1011 And DC-10

Thu Sep 02, 2010 4:12 am

Quoting tdscanuck (Reply 13):
The Bugatti Veyron is unquestionably more technically advanced than the Volkswagon Beetle...guess which one sold more.

The Beetle sold more, I would assume.

Quoting Max Q (Reply 14):
There is no issue for rebuttal, the L1011 was more technically advanced than the DC10 without doubt.


That may be, however, the DC-10 sold more than the L1011 did.
A Safe Flight Begins With Quality Maintenance On The Ground.
 
sfotom
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RE: Technical Differences Between L-1011 And DC-10

Thu Sep 02, 2010 4:27 am

I would question the L-1011s having better hydraulic redundancy. In 1981 Eastern Airlines had an L-1011 engine fan shaft fail on takeoff on #2 engine. The now unconnected fan drove forward into the s-duct and came apart. It caused the complete failure of hydraulic systems A, B & D. Several lines carrying hydraulic system C were damaged but only by luck did they not also leak. In addition to the hydraulic failures some of the flight control cables were severed, and the fuel supply line to #2 engine was punctured. After this a hydraulic fuse was added in the tail area to prevent a recurrence.

The aircraft was N309EA and the report information can be found here. http://hfskyway.faa.gov/HFTest/Bibli...Maintenance/Eastern%20Airlines.pdf

I would also say that only the exemplary actions of the Delta crew on the L-1011 that took off with a snapped elevator cable prevented a tragedy in that case.

To be honest, the DC 10 and the L-1011 were two very different aircraft, each took a very different approach to their design. There are mechanics that I know and highly respect that feel that the L-1011 was the best aircraft ever built, and there are those I have equal respect for that hated it. I have worked on both, and my personal opinion is that the L-1011 overextended it's reach for what the technology of the time was able to reliably and consistently support. It also made a difference how well the aircraft was maintained. If you took good care of the L-1011 maintenance wise, then it's daily maintenance workload was not too bad, but I saw in some airlines that weren't willing to expend the resources in maintenance the L-1011 would become a maintenance pig much more rapidly then other types.
 
Max Q
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RE: Technical Differences Between L-1011 And DC-10

Thu Sep 02, 2010 5:02 am

Quoting tdscanuck (Reply 16):

In that case, design was a contributing factor but not the only one. *If* you latched the cargo door properly, it worked just fine. The design problem was that you could get the door into a state (by using unreasonable force on the mechanism) where it appeared to be locked but wasn't. This is, obviously, a giant design flaw but it wouldn't have caused an accident if people hadn't tried to strong-arm the latching mechanism instead of checking why it was so !#%!@% hard to close.

In other words, it was a bad design.

Quoting sfotom (Reply 20):



I would question the L-1011s having better hydraulic redundancy. In 1981 Eastern Airlines had an L-1011 engine fan shaft fail on takeoff on #2 engine. The now unconnected fan drove forward into the s-duct and came apart. It caused the complete failure of hydraulic systems A, B & D. Several lines carrying hydraulic system C were damaged but only by luck did they not also leak. In addition to the hydraulic failures some of the flight control cables were severed, and the fuel supply line to #2 engine was punctured. After this a hydraulic fuse was added in the tail area to prevent a
recurrence.

Not sure why you would 'question the hydraulic redundancy here'



Im this case the hydraulic redundancy allowed the Flightcrew to fly the Aircraft back to a successful landing after an unprecendent
and incredibly destructine uncontained engine failure.



Contrast this incident with the disastrous uncontained failure of the #2 engine on the UAL DC10 that left the Aircraft completely without any flight controls after the loss of all hydraulics.



Many passengers paid the ultimate price that day, but for the skill of Al Haynes and his crew there would have been no survivors at all.
The best contribution to safety is a competent Pilot.
 
sfotom
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RE: Technical Differences Between L-1011 And DC-10

Thu Sep 02, 2010 6:32 am

Quoting Max Q (Reply 21):
Not sure why you would 'question the hydraulic redundancy here'

If in the case of the Eastern L-1011, the C hydraulic system survived because it had been routed through a more safe area, or that it had be protected by structure that had been beefed up for that purpose, or if it had been fitted with a system to isolate that line in the event of leakage, then I would give credit to the engineering work for the safe return of the aircraft. As it was, non of the above applied. The C hydraulic lines passed through the same area damaged by the uncontained failure of #2 engine as the other hydraulic lines and it only survived by dumb luck, not by design.

If you compare this to flt 232, if only one of the blades had taken a slightly different trajectory then hydraulic system 1 or 3 might have survived giving that flight a very different ending. In both cases, hindsight shows us that neither aircraft had sufficient redundancy to meet the standards that we would want them to have.

Both aircraft had a lot of good design work put into them. Both aircraft have their strengths and weaknesses. Both aircraft when maintained and operated properly gave good service to safely move people around the world. I don't believe that the DC 10 deserved it's negative reputation, and I think the L-1011 got some lucky breaks which could have gone the other way.
 
stratosphere
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RE: Technical Differences Between L-1011 And DC-10

Thu Sep 02, 2010 7:33 am

Quoting sfotom (Reply 22):
I don't believe that the DC 10 deserved it's negative reputation, and I think the L-1011 got some lucky breaks which could have gone the other way.

I think you might be right but even though I never worked the L1011 it was more thought out with regards to redundancy. The DC-10 was playing catch up at the time. But you have a good point Bad luck exposed the DC-10 vulnerabilities. But take AA 191 in 1979 would not have happened with the L1011 the slats on the L10 would have locked and not retracted like they did on AA 191. I really like flying on the DC-10 and the L1011. As for working on them the DC-10 was a maintenance pig and actually I think the L1011 was challenging as well. As for pilots that flew them pilots loved both a/c. Our friend PGNCS will attest to how much he loves the L1011 over any other a/c. Too bad both a/c especially the L1011 are a tough find as far as flying on one.
 
474218
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RE: Technical Differences Between L-1011 And DC-10

Thu Sep 02, 2010 12:53 pm

Quoting sfotom (Reply 20):
I would also say that only the exemplary actions of the Delta crew on the L-1011 that took off with a snapped elevator cable prevented a tragedy in that case.

Having worked with the L-1011 for over thirty years we never had a broken elevator drive cable. The incident are referring to was caused by a failed bearing in the elevator drive quadrant. The failed bearing allowed the quadrant to tilt and jam. This happened prior to T.O. during the controls check. After reviewing the incident Lockheed installed a jam detector in the system.

Quoting tsugambler (Reply 18):
That's interesting, I never knew that Lockheed had any sort of negative reputation re: product support.

Because of the Electra Lockheed went in the opposite direction with the L-1011 product support. Written to each purchase contract was a clause that Lockheed would continue to provide support as long as one L-1011 was still in service with an original purchaser. While I am a little bias because I spent 22 years in L-1011 product support, our support was second to none. If fact when Airbus was trying to sell A310's to an L-1011 operator, they insisted that Lockheed provide the support for them. Several meetings were held in Toulouse and Burbank on the subject, before we backed out of the project.

L-1011 support is on going as I just got a fax from them this week covering a new FAA requirement.
 
Pihero
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RE: Technical Differences Between L-1011 And DC-10

Thu Sep 02, 2010 6:18 pm

Quoting PGNCS (Reply 1):
This is way too big a topic
Quoting 474218 (Reply 6):
The technical difference between the DC-10 and the L-1011 are easy to explain
Quoting Max Q (Reply 14):
the L1011 was more technically advanced than the DC10 without doubt

All the above three quotes sum nicely up the comparison.
What we could say, as a fact, is that the Tristar was designed from it's start as a"system", built around the first civilian integrated avionics, and that's constitutes the very difference between both tri-jets.
While, IMHO, the Ten was just another airplane, the Tristar had superlative handling qualities, an autopilot which was way ahead of all the others (in all probability the summit of the analogic solution) and still superior to the 744 which came fifteen years lmater with digital systems.
In many ways, looking at Airbus architectures -especially the hydraulics - is seeing the heritage of the "Tripod". (Before the 380, that is ...)
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broke
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RE: Technical Differences Between L-1011 And DC-10

Thu Sep 02, 2010 8:32 pm

The DC-10 was an enlarged DC-8/DC-9 airplane. Many of the major structural elements were identical in shape but only larger than those on the DC-8/DC-9 and the main advance in structures was in the size of the airplane. Systems were essentially the same as on the earlier airplanes.

The L-1011 was a new airplane with an analog avionics package and was the most electronic airplane of its day. What hurt the airplane sales was the financial difficulties of Rolls-Royce (bankrupcy) and then the the reliabilty of the RB-211-22C engine. The inflight shut-down rate of the -22C was about 1 for every 100 flights and when that occurred, the airplane would be two engine ferried to a maintenance facility for an engine change. This happened often enough until a second engine would have to be shut-down on the ferry flight and then things got really exciting. Eastern has a least 5 single engine flights that I known of. After that, 2 engine ferries were severely restricted and, often, a replacement engine with tooling and mechanics were sent to the airplane wherever it ended up (like Billings, Montana for instance). The conversion from the -22C to the -22B (I do not why the letter designation regressed, but is did.) did improve engine reliability somewhat, but it was still an iffy engine. The -524 was a much better engine.
 
Viscount724
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RE: Technical Differences Between L-1011 And DC-10

Thu Sep 02, 2010 11:39 pm

Quoting broke (Reply 26):
The DC-10 was an enlarged DC-8/DC-9 airplane. Many of the major structural elements were identical in shape but only larger than those on the DC-8/DC-9 and the main advance in structures was in the size of the airplane.

What structural elements of the DC-10 were identical in shape to those on the DC-8 and DC-9? I've never herd that before. There's certainly nothing in common externally.
 
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Jetlagged
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RE: Technical Differences Between L-1011 And DC-10

Fri Sep 03, 2010 2:11 am

Quoting Max Q (Reply 21):
In other words, it was a bad design.

It was a weak design, but safe if used correctly.
The glass isn't half empty, or half full, it's twice as big as it needs to be.
 
Max Q
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RE: Technical Differences Between L-1011 And DC-10

Fri Sep 03, 2010 4:19 am

Quoting jetlagged (Reply 28):

It was a weak design, but safe if used correctly.

So was the Hindenburg..
The best contribution to safety is a competent Pilot.
 
wn700driver
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RE: Technical Differences Between L-1011 And DC-10

Fri Sep 03, 2010 4:31 am

Quoting tdscanuck (Reply 13):
The Bugatti Veyron is unquestionably more technically advanced than the Volkswagon Beetle...guess which one sold more.

In what way? It's faster? I can't imagine the cost of ownership, actual usefulness or reliability on one of those is anything like acceptable. Probably not the case with the Beetle, I should think...

Quoting jetlagged (Reply 11):
The infamous Chicago and Paris DC-10 accidents were not caused by design problems, for example, but poor design contributed to the result.

I'm not sure how. Wasn't that type of engine change out procedure already declared a no-no at the time by McD? If so, the only poor design would be AA MX.

WRT the THY incident near Paris... That was a clear cut case of the ramper not following procedure and muscling a door shut that obviously wasn't secure.

I'm not saying the same things could have easily happened to the L-1011, but they really can't be faulted by the design of the -10.

Now the UAL "incident" at Sioux Falls could be said to be a design inadequacy, WRT the placement and redundancy of those HYD systems...

Quoting Max Q (Reply 14):

There is no issue for rebuttal, the L1011 was more technically advanced than the DC10 without doubt.

I have heard that on the TriStar the FE position is largely superfluous. If so, that would certainly help make your point, given that it was designed in the 1960's!

Quoting tdscanuck (Reply 16):
a giant design flaw but it wouldn't have caused an accident if people hadn't tried to strong-arm the latching mechanism instead of checking why it was so !#%!@% hard to close.

I would think that that is much more a training issue than anything to blame straight up on design. I will concede though, that by standards today's near fool-proof cargo door latching mechanisms, it probably requires a bit extra attention (pre-correction).

Quoting sfotom (Reply 22):
I don't believe that the DC 10 deserved it's negative reputation, and I think the L-1011 got some lucky breaks which could have gone the other way.

True. But we should not let that take away from the fact that the L1011 is/was a truly magnificent AC. Would have been great to see Lockheed stay in the game a bit longer. I often wonder what today's version, likely a "TwinStar" would be like...
Base not your happiness on the deeds of others, for what is given can be taken away. No Hope = No Fear
 
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Starlionblue
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RE: Technical Differences Between L-1011 And DC-10

Fri Sep 03, 2010 6:09 am

Quoting Max Q (Reply 9):
The L1011 never had a design caused accident.

Not many Aircraft can claim that.

777, 330*/340, 318-321 are all airliners with no design caused accidents. 757 and 767 as well unless I am mistaken.


*AF 330 crash still not solved at this time.
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thegeek
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RE: Technical Differences Between L-1011 And DC-10

Fri Sep 03, 2010 6:26 am

A 767 crashed due to a reverser deploying in flight. I don't think that one qualifies.
330/340? Until AF447 that was probably true, but I'd struggle to accept that now, or at least it's under a pretty dark cloud.
777: what about BA38? An engine problem AIUI, but still a design limitation IMO. I suppose you could still argue that there were no airframe design limitations with the 777.

Can't think of any design caused accidents for the A320 or even the 737 but I'm sure there are some for the latter.

But going back to the L1011 incident where it lost 3/4 hydraulic systems, you'd have to say that if one of the systems wasn't there, there was at least a 25% chance(*) of the same failure causing a complete hydraulic failure and presumably a crash.

(*) If A, B or D was removed there would be no crash.

Both the DC-10 and the MD-11 were less safe than they should have been at service entry. At least the 767's flaw only caused one accident.
 
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Starlionblue
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RE: Technical Differences Between L-1011 And DC-10

Fri Sep 03, 2010 7:21 am

Good info thegeek. I am on the fence about including problems that are specifically engine related such as Lauda Air 767 or BA 777 since engines are such a "separately designed" component. Then again lots of components are designed by different teams within and without companies, for example landing gear may be provided by another company in part of entirely, as well as avionics and other stuff.

Quoting thegeek (Reply 32):
Can't think of any design caused accidents for the A320 or even the 737 but I'm sure there are some for the latter.

Rudder reversal accidents on the 737 qualify.

Quoting thegeek (Reply 32):
330/340? Until AF447 that was probably true, but I'd struggle to accept that now, or at least it's under a pretty dark cloud.

It would be incorrect to count AF447 until we really really know one way or another. For all we know a crewmember could have entered the cockpit, knifed both pilots and dived the aircraft into the water. Not saying this scenario is probable, just pointing out that there is not a lot of evidence for any particular hypothesis at this point, perhaps excepting pitot tube stuff.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
DH106
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RE: Technical Differences Between L-1011 And DC-10

Fri Sep 03, 2010 8:17 am

Quoting Starlionblue (Reply 33):
Can't think of any design caused accidents for the A320 or even the 737 but I'm sure there are some for the latter.

I think the early 737-100/200's had a hydraulic system design flaw that caused an accident.
The reverser hydraulics required the weight on wheels switch to be made before power was applied to move the reverser buckets. This limit was initially designed to be the case for both the reverser open and stow lines, with the effect that a deployed reverser would not stow again should the aircraft become airborne again after initial reverser deployment. This was the main factor in the Pacific Western 737 crash at Cranbrook, BC - 11 Feb 1978.
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Starlionblue
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RE: Technical Differences Between L-1011 And DC-10

Fri Sep 03, 2010 8:23 am

You're quoting the wrong guy DH106.  
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
Max Q
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RE: Technical Differences Between L-1011 And DC-10

Fri Sep 03, 2010 8:34 am

Well, I cannot agree that the A320 has had no design caused accidents.


Lufthansa had a fatal runway overrun in Warsaw with an A320. After touchdown the Captain was unable to deploy spoilers or reverse as the Aircraft computers were not 'satisfied' it was on the ground. The design also did not allow him to override this function manually.


Despite his best efforts he was unable to stop the Aircraft and two people (one cremember and one passenger) were killed when they departed the runway.


This is just one episode I can think of. To be fair the inflight deployment of thrust reverse with one of Lauda Air's 767's over Thailand must count as a fatal design error as well. In that case everyone died.



That does narrow the list of Aircraft with no design caused accidents considerably. When you consider how long the L1011 has been in service it's record is really quite outstanding.




Compare it to the MD11 for instance !
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thegeek
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RE: Technical Differences Between L-1011 And DC-10

Fri Sep 03, 2010 8:34 am

With the reverser on the 767, you can still blame the airframe for that one as it is supposed to be designed to not fall out of the sky in that scenario. It is also possible that the reverser deploying is an airframe flaw or part of the airframe, but that is moot because of the prior point.
 
DH106
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RE: Technical Differences Between L-1011 And DC-10

Fri Sep 03, 2010 9:00 am

Quoting Starlionblue (Reply 35):
You're quoting the wrong guy DH106.

Yes, sorry Starlionblue - too easy to highlight some text then click on another button which gives that result  Wow!
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Starlionblue
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RE: Technical Differences Between L-1011 And DC-10

Fri Sep 03, 2010 9:31 am

Quoting Max Q (Reply 36):
Well, I cannot agree that the A320 has had no design caused accidents.

Fair enough. So we're left with 330*/340 and L-1011.

Quoting Max Q (Reply 36):
When you consider how long the L1011 has been in service it's record is really quite outstanding.

Certainly true! A great aircraft which I have had the pleasure to fly in only twice. CX BKK-HKG and some "white aircraft" charter airline LHR-ARN. I remember crying my eyes out because I didn't have a window seat on BKK-HKG (I must have been about 12). Some nice pax traded with me and I could see the flaps moving and such. It amazed me how much the wing deconstructed itself.

The L-1011 also has the honor of starring in a TV movie favorite of mine: "The Langoliers".



*Barring some result from the investigation which points at the design. Basically we just don't know at this point.
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thegeek
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RE: Technical Differences Between L-1011 And DC-10

Fri Sep 03, 2010 9:39 am

Quoting Max Q (Reply 36):

Lufthansa had a fatal runway overrun in Warsaw with an A320. After touchdown the Captain was unable to deploy spoilers or reverse as the Aircraft computers were not 'satisfied' it was on the ground. The design also did not allow him to override this function manually.

Which actually was a similar situation to the one in Brazil, although a misunderstanding in the cockpit regarding what was actually happening was really the main cause there. Certainly the crew have to shoulder a large portion of the blame, but perhaps not all. While there was a "retard thrust" announcement, or something like that, there was no "no spoilers" announcement once they were on the ground.
 
474218
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RE: Technical Differences Between L-1011 And DC-10

Fri Sep 03, 2010 12:17 pm

Quoting broke (Reply 26):
The conversion from the -22C to the -22B (I do not why the letter designation regressed, but is did.) did improve engine reliability somewhat, but it was still an iffy engine.

There where only a hand full of RB2111-22C engines built and all were either modified to -22B configuration (by RR service bulletin 72-2500) or removed from service by December of 1974. And while the early RB-211's had a few problems, unlike their major competitor they did not have to be thrown away, as they could be rebuilt.

Quoting wn700driver (Reply 30):
WRT the THY incident near Paris... That was a clear cut case of the ramper not following procedure and muscling a door shut that obviously wasn't secure.

I'm not saying the same things could have easily happened to the L-1011, but they really can't be faulted by the design of the -10.

The real problem with the THY DC-10 started on the production line when the door was rigged. After final assembly the plane was moved to the flight line, were it sat because the customer (ANA) had cancelled their order. Then the AA Windsor incident occurred and the door rigging drawing was revised to insure proper engagement of the locks. However, the revised rigging was not accomplished on the THY plane and the rest, sadly, is history.

The same thing could not happen on the L-1011 because the door is latched electralily not manualy.

Quoting Starlionblue (Reply 39):
The L-1011 also has the honor of starring in a TV movie favorite of mine: "The Langoliers".

I missed my chance for immortality on the "Longoliers". One day my boss called me in his office and asked me if would like to work on a movie. I said sure, it was the "Longoliers" and they were leasing a an L-1011 and I was to be the technical consultant. Will as it turned out the film company leased the TriStar from Five Star and they provided their own consultant.
 
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Faro
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RE: Technical Differences Between L-1011 And DC-10

Fri Sep 03, 2010 1:22 pm

Quoting Max Q (Reply 14):
There are clear cases of accidents caused by bad design. The DC10 cargo door design was one, the failure of this door was a direct cause in the loss of control and fatal crash of the THY Aircraft in Paris.

The Paris THY accident was not caused by bad design, it was caused by regulator apathy. A similar cargo door blow-out was experienced on AA96 three years before near Windsor, Ontario. IIRC, an airworthiness directive corrected the issue on US airframes; the THY airframe was a whitetail (if my memory serves me right) at the time and did not have the rectification incorporated into the cargo hold door. The regulator blundered...

Faro
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Faro
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RE: Technical Differences Between L-1011 And DC-10

Fri Sep 03, 2010 1:38 pm

Quoting Pihero (Reply 25):
the Tristar had superlative handling qualities

See also PGNCS's reply 6 in this thread:

Handling Qualities Widebody Vs Narrowbody (by Faro Nov 11 2009 in Tech Ops)?

"The best control harmony and maneuverability I have personally flown in a large aircraft is undoubtedly on the L-1011, which was the most pleasing aircraft to hand fly I have ever known."

Faro
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OldAeroGuy
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RE: Technical Differences Between L-1011 And DC-10

Fri Sep 03, 2010 1:54 pm

Quoting Starlionblue (Reply 39):
Quoting Max Q (Reply 36):
Well, I cannot agree that the A320 has had no design caused accidents.

Fair enough. So we're left with 330*/340 and L-1011.

The 757 still qualifies as well.
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MD-90
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RE: Technical Differences Between L-1011 And DC-10

Fri Sep 03, 2010 2:46 pm

Quoting AirframeAS (Reply 12):

If someone were to tell me that, my rebuttal would be "If it (L-1011) was more technically advanced, then why did the DC-10 outsell the L-1011?"

1. No matter how advanced an aircraft is, regardless of how much better it is than its competition, if you can't deliver them on time according to contract it isn't going to sell well.

2. Lockheed made a serious mistake in using a belly fuel tank in the L-1011 that precluded the design from ever being able to utilize a third MLG bogey. If the L-1011 had been able to grow in MTOW like the DC-10-30 it might've sold more.

3. 386 DC-10s built compared to 250 L-1011s shows that Douglas sold 64% more DC-10s, which is a pretty commanding lead but the fact is neither company made money on their respective programs overall, although Douglas again had a big leg up with the 60 aircraft KC-10 gift from the government thrown to a grumpy McDonnell.
 
tdscanuck
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RE: Technical Differences Between L-1011 And DC-10

Fri Sep 03, 2010 3:49 pm

Quoting Max Q (Reply 21):
In other words, it was a bad design.

All designs are bad if used incorrectly. Like most aircraft accidents, the DC-10 door issues is a confluence of multiple things...design, maintenance, and operation.

Quoting wn700driver (Reply 30):
Quoting tdscanuck (Reply 13):
The Bugatti Veyron is unquestionably more technically advanced than the Volkswagon Beetle...guess which one sold more.

In what way? It's faster? I can't imagine the cost of ownership, actual usefulness or reliability on one of those is anything like acceptable. Probably not the case with the Beetle, I should think...

The Veyron implements several technologies that just aren't on the Beetle, which enables the ridiculous performance. But the Beetle sells far better because it does the required mission at far less cost, which was the point...just being technically advanced does not translate to market success.

Quoting thegeek (Reply 37):
With the reverser on the 767, you can still blame the airframe for that one as it is supposed to be designed to not fall out of the sky in that scenario.

Reverser control is an airframe function, not an engine function, on a 767. The Lauda accident was entirely an aircraft problem.

Tom.
 
474218
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RE: Technical Differences Between L-1011 And DC-10

Fri Sep 03, 2010 4:02 pm

Quoting MD-90 (Reply 45):
Lockheed made a serious mistake in using a belly fuel tank in the L-1011 that precluded the design from ever being able to utilize a third MLG bogey. If the L-1011 had been able to grow in MTOW like the DC-10-30 it might've sold more.



The L-1011 does not have any "belly tanks" all the fuel is in the outer wings and the center wing box. I think this is the same with the DC-10-30 and -40's?

The reason the DC-10 need the center line main gear is because the main gear could not support the added weight of the -30/-40.

The RAF operates their TriStar tankers at 540,000 lbs MTOW, which is 110,000 lbs above the MTOW of an L-1011-1. The landing gear strut, piston and truck are the same, different axles being the major change needed to support the additional weight.
 
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RE: Technical Differences Between L-1011 And DC-10

Fri Sep 03, 2010 4:04 pm

Quoting tdscanuck (Reply 46):
Reverser control is an airframe function, not an engine function, on a 767. The Lauda accident was entirely an aircraft problem.


Not on 767's with Rolls Royce engines.
 
Max Q
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RE: Technical Differences Between L-1011 And DC-10

Fri Sep 03, 2010 8:27 pm

Quoting thegeek (Reply 37):



With the reverser on the 767, you can still blame the airframe for that one as it is supposed to be designed to not fall out of the sky in that scenario. It is also possible that the reverser deploying is an airframe flaw or part of the airframe, but that is moot because of the prior point.

Sorry, but anything that Boeing certifies on it's Aircraft whether its a thrust reverser or a coffee maker has their 'seal of approval'


And as such they take full responsibility for it.
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