DC-10 vs L-1011
 

Just curious if there are any pilots out there who have flown both aircraft. Which one do you think was better more reliable and a joy to fly? Anyone who is an knowledgeable on both aircraft, please chime in. Thank you.:p

I'll jump into this, having flown all three widebody tri-jets (and I'll throw in the MD-11 at no extra charge).

I'll say this for the DC-10: it does fly nicely. I was actually pleasantly surprised at how well it handled. And the GE engines are very good powerplants.

The MD-11 is not quite as agreeable (I don't think it's bad, just different) - the smaller stabilizer makes it a bit touchier, particularly in pitch. The initial ground spoiler deployment on the -11 is virtually worthless (they only partially deploy until the nosegear is on the ground to prevent a tailstrike) - I don't recall the DC-10 being so light on the gear after touchdown. The aircraft feels like it's ready to hop back into the air at the slightest provocation. I like that the -11 has tremendous amount of power, I'm flexing at altitudes/temperatures I never would have dreamed of.

Then there is the L-1011. It's really hard to find fault with it. It handled well, had tons of redundancy, and was WAY ahead of it's time. The pitch trim system is the best of any aircraft I've ever flown, you had control over virtually everything (you could actually control the pitch in the event of a jammed stabilizer by deselecting spoiler panels and deploying the remaining ones), the spoilers were infinitely selectable (unlike the 3 notches on the Douglas), the ground spoilers worked very well initially and fully deployed. It has the biggest cockpit of any airliner I know of (much roomier than the Douglas products).

Systems-wise, the L-1011 design is still far superior to the DC/MD. First, the DC-10/MD-11 are virtually identical systems wise. Douglas did very little re-engineering of the systems when they created the MD-11, they simply automated the cockpit controls and added EFIS and an FMC.

Hydraulics are one of the DC/MD's weaknesses - three systems with eight power sources vs. four with eleven power sources (IIRC) on the 1011. The L-1011's system architecture also provides more redundancy than that of the DC/MD. Even after Douglas refitted the aircraft with the "Sioux City valve" the system is still a weak link. Lose one system and you will lose some capability on the aircraft. On the L-1011, with one system loss you still have everything operating.

Electrically, both types are pretty good. I like the architecture of the L-1011 better in that the APU can (and is) paralleled with the engine generators on the tie bus, but so far I haven't had any problems with the DC/MD system where the APU NEVER is on the tie bus. I do like the no-break power transfer system on the MD.

The L-1011 APU is also weak in the air delivery department (noticed mainly on engine starts with low pressure). I don't recall the DC having that problem, and the MD definitely doesn't (excepting high altitude airports, but that's to be expected).

Air systems on all three work well enough, the IIRC the L-1011's was a bit more versatile, but not a huge difference. The DC/MD's don't have the "steam train" chugging the the L-1011's packs occasionally did, and the MD's temperature control system does a better job than the L-1011/DC-10.

Fuel systems are a toss up. The L-1011 wins in the simplicity department (at least from the engineer's panel), but the DC/MD gives you more control and versatility (and more ability to mess things up). If it were just that, there would be no clear winner on this one. Unfortunately, the DC/MD has one other minor vice - if you lose all AC electrical, the #2 engine WILL fail due to fuel starvation. Just in case you don't have enough to do with the widebody equivalent of a "9 light trip," we'll throw in an engine failure to make it sporting. Really, they couldn't come up with a better system?!?

Aside from that minor consideration, I think the fuselage mounted #2 engine is better than the tail mounted one for the DC/MD - it doesn't create the pitch issues when doing one and two engine inoperative approaches that the high mount of the DC/MD does. Also the loss of #2 on the DC/MD near V1 causes an auto-rotating tendency with can lead to an early liftoff or tailstrike.

While the RB-211 is a good powerplant, the original -22B's weren't too powerful, and it does not like cold weather (Note - the later RB211's such as on the 757 are a different animal). It wasn't uncommon to have 3+ minute starts, and more than once I've come close to the 5 minute starter duty cycle. Also, the pneumatic reversers were somewhat prone to sticking. Again, it wasn't unheard of to have one MEL'd and pinned out (deactivated). I haven't observed any such problems on the DC/MD.

Flight control-wise, the DC/MD's are very dependent of slats (having only slotted flaps, not Fowlers) - hung up slats result in very high approach speeds (more so than the L-1011 with Fowler flaps). This combined with the fact that the original slat actuators on the DC-10 did not lock when extended (but were held extended only by hydraulic pressure) directly contributed to the crash of AA191 at KORD. To me, that is a serious design flaw. The L-1011 also had DLC (Direct Lift Control) - on approach with landing flaps, the spoilers biased up 7 degrees and then modulated between 0 and 14 degrees in response to pitch inputs from the control wheel, greatly reducing the amount of pitch change while tracking the glideslope. Worked great, particularly on a coupled approach! Also the L-1011 had a speed "doughnut" on the ADI, which sensed AOA, configuration, acceleration, phase of the moon, and sever other inputs. It took some getting used to, but once you understood what it was telling you if you couldn't hold your approach speed within one or two knots, you just weren't trying. The -500's also had MDLC (maneuvering direct lift control) and ACS (active control system) as part of the wing extension. Essentially ACS would deflect the ailerons to unload the outboard section of the wing in turbulence, MDLC would deploy the spoilers in maneuvering flight (though I'd be lying if I tried to tell you the purpose at this moment).

Also in the design flaw department, there is the whole cargo door/floor venting debacle on the DC-10. How Douglas got away with that travesty I will never know. History indicates the issue has been successfully resolved, but it never should have occurred in the first place (or should have been resolved after the first incident).

As far as reliability, it seems to me that all of them do reasonably well IF you keep up on maintenance (don't let little things slide) and have mechanics who really know the airframe and are provided with the resources to maintain them. Attempt to cut corners, and you will pay the price in reliability. Also, keep them flying - airplanes hate to sit (when we flew the heck out of the L-1011's during the CRAF activation reliability was quite good).

My ultimate analysis is pretty much this:

I picture a bunch of engineers sitting around tables at both Lockheed and Douglas. The Lockheed engineers are focused on producing the best aircraft possible. The Douglas engineers are focused on producing an airplane before Lockheed. On the whole, the design of the DC-10 seems like it was cobbled together without a great deal of thought, and it shows. Even items as small as the space for a chart case (too small on the DC/MD, and the cute fold out table is mounted too low to be useful with a chart case there), to cockpit lighting (poor on the DC/MD), or the passenger door system (stone simple of the L-1011, unnecessarily complicated on the DC (and with at least three different variations on the ones I flew).

Two old sayings come to mind:

1) Lockheed has always built the most technologically advanced aircraft available. Unfortunately, they've never figured out how to make money doing so.

and

2) Lockheed should design them, Boeing should build them, and Douglas should market them.

Sorry to go on so long - but you did ask! :D

Wow...bcrosier, you have flown the 3 jets I can honestly say I've wanted to fly the most. Thanks for letting me live vicariously through your descriptions :D

I better not let my old man see this post. He's been an engineer on both (and many other Lockheed products) and all he talks about is the L10.

Excellent little essay Mr. bcrosier. I like the short descriptions and the (probable) ramifications...if only each chapter of a AFM had a short /preview/review or summary like that. If you assigned a weighted point system I'd think the L1011 would come out leagues ahead over the DC-10. But then, as I recall the L1011 cost about $1.5 million more than the DC-10 when new - so less takers. (Also their were delays in engine development/certification, not Lockheed's problem, but it cost them).

The L1011 is/was the nicest cockpit I've been in, seemed to be laid out exceptionally well. I've never flown it, but it was my favorite jump-seat living room.

whoaa! this was clearly over the top. many thanks bcrosier for the excellent essay you took the time to write. it is much appreciated and extremely informative. :)

I flew the 767 for about 3 years then the L-1011 for the last 3 years of my time at TWA.

The L-1011 flight deck, as you say, was awesome. But, the first 10 TWA 767s (all they had when I was there) had a nice flight deck, too, because they were put together with a F/E station. Then, ALPA lost the F/E arbitration, so these 10 TWA 767s went from Seattle to Boeing ICT for removal of the F/E station and reconfiguration of the pilots' systems panels. Fortunately for the crews it wasn't feasible to move the cabin bulkhead forward.

I jump-seated on some of those TWA 76's too. There was plenty of room to lay out and nap back there, or, install a self leveling pool table.

The DC10 had good views and was wide (the 747 never comes close to cockpit comfort/views) but riding transcon on a nice day in the L1011 was just splendid.

Thinking of it, I can't remember a systems/airframe issue on the L1011 that led to or was attributable to an accident. There's the DFW micro-burst & the Saudi cabin fire due to a on-board cook stove and landing pressurized, but really, I can't come up with anything else. Wait, there's the JFK RTO with false shaker activation, maybe that counts? Certainly no catastrophic systems/airframe/control failures?

Only a 3 cent lightbulb one night over the Everglades :(

Oh yeah, I totally forgot about that one (the aftermath being perhaps the start of CRM/human factors, of course the DC-8 in PDX 6 years later, is what which cemented the path to CRM...)

I suppose you could call a light bulb part of a system, and in that case consider it something that led to an accident (perhaps, more correctly, a factor), but I'd say in that circumstance it is certainly not not attributable, like a faulty cargo door handle leading to a door failure, leading to the floor failure, the total hydraulic failure, etc. (Paris, 1973).

There was also Saudi Flight 162, where a tire exploded and penetrated the cabin; two people were "sucked" out of the airplane. In 1981, an Eastern L-1011 had a catastrophic #2 engine failure, and the crew had to land with half their control surfaces working (and use differential thrust). And, as you already mentioned, TWA 843.

Ain't that the truth! Had I had the opportunity, it would have been the L-1011....hands down!:cool:



atp

The Lockheed C-5 is an amazing flying machine. I loved it, and will always respect it. Lockheed was way ahead of its time in '69.

That said, having now flown the 757, 767, and 747-400, "If it ain't Boeing, I ain't going!" Nothing else compares.

Didn't know about the other Saudi incident. But the score is still L1011: 0 to the DC10: 2 (minimum)

Nice added details but a gear light, tire blow-out cabin penetration of debris, catastrophic failure of engine probably wouldn't be considered a system failure or engineering weakness of the airframe or controls.

Of course I forgot about the triple flame-out on a L1011 due to oil o rings being incorrectly installed on all engines. After drifting down to a fairly low altitude they got #2 started and into Miami. That doesn't count either. (Now you can tell I'm furloughed without a life...all this time lingering on this thread...)

TWA almost lost two for a systems type failure. One was a J Duct overheat they couldn't control and they just made it on the ground at SFO before a likely fatal fire broke out.

Another was an improper fuel line fitting (counterfeit part I believe) that caused an uncontained fuel leak on the No. 1 engine pylon. This was midway between LAX and HNL. They diverted to Hilo and landed with very little fuel remaining. I recall this one partially crew error. Had they pulled the fire pull early on (which they eventually did) they would have stopped the leak before they lost a whole lot of fuel. The leak was between the fire fuel shut off and the normal engine fuel shut off valves.

Oh, and early in the life of the fleet a flight westbound was down to minimum flight control hydraulics over ALS as I recall and diverted into LAS instead of going to LAX. D system only remaining if I recall the flight control systems correctly.

Well there you go, it seems nothing is immune to failure. Interesting to find out the internal stories, the failures, the "saves", the ones that don't make it to the public or even industry press. Can't say which is better or safer, even with all the actual data such as number of airframes/hours flown/cycles/failures it would be quite the task.

the UPS 767 has tons of room in the cockpit. for some reason there bulkhead is placed a few feet back farther than the cockpits I have seen in passenger carrying 767's.

It's placed further aft to allow room for the captains wallet!

lmao... well done. :p

My understanding is that the autopilot-disengage was too sensitive. As the crew were leaning over to try to remove the translucent button covering the bulb, Loft nudged his control yoke, which disengaged the autopilot. That sent the aircraft into a slow descent. Lockheed designed the two control yokes so that each could have different "force settings" required to disengage the autopilot. Unfortunately, Loft's was set too low. Also, Lockheed should have built-in a louder audible signal that the autopilot had disengaged. If any of those features were in place--particularly the latter--Flight 401 wouldn't have crashed. And, who can forget about the hauntings? Loft and Repo haunting L-1011s that had parts salvaged from Aircraft N310EA (the one that crashed). Loft was the pilot; Repo was the flight engineer. Loft was killed in the crash, while Repo died two days later in a hospital.

Welcome back time traveler!

My dad flew the L-1011 for the big airline in the southeast (that's still in business). He instructed on it too and I was fortunate enough to get quite a bit of sim time in her. What a fantastic airplane. He used to let me sit on the engineers seat and act as a quasi engineer to the guys up front, reading checklists and telling them stuff that was wrong with the plane to prompt them to do stuff. Super neat. I remember just two things distinctively...HAT in the window (Heading/Altitude Select/???) and the DLC and MDLC. Any airplane that you can get into the pilot seats from either side is pimp in my book.

thread is five years old

With math skillz like that it's no wonder that you're a pilot. :cool:

1011 vs. DC10
 

I always thought that the 1011 was engineered better than the 10 simply because the 1011 #2 has an S-duct.

I'm not an engineer, but was told by structure mechanic, who worked in the Palmdale plant in where it was built that the S-duct puts the thrust of all three engines on one plane. Unlike the 10, the #2 is located above the 1 and 3 engines.

yes, like your spelling skillz

Story was Lockheed's L10 sim in Palmdale had a airport programed called Anytown, USA. No approach, no VASI, and 4000' long. It had a Mc Donalds immediately off the end of the runway. Sporty, and a sense of a humor.

L1011 was awesome. When it broke, it broke hard. When it ran, it wasn't like anything else out there. The Direct Lift Contol was magical during a coupled approach, maintaining the glide slope with the use of spoilers, leaving the pitch locked in and comfortable. No other bird did that at the time (like so many other attributes of the L10). Has any other airframe used DLC since? Can't think of one, maybe there is.

Anyway, as usual, I'm entering the conversation a little late, LOL. Loved that airplane, though. Miss the TWA family, as well.

Civilian aircraft I don't know of any. I believe the F14 and S3 had it.

Defemce Contractor L1011's?
 

Anyone know or think this actually going to happen?

AGD SYSTEMS Corporation Announces Capabilities with Addition of Six (6) Tristar L-1011 Tankers for Aerial Refueling, Cargo and Medivac Missions - PR.com

DC-10 vs L-1011
 

Sat in the L1011 cockpit Jumpseat once. Freaking picture window.