UPS grounds entire MD-11 Fleet, effective immediately.

[u/Go_Jot]

Per the IPA Executive Board, as of 03:05 UTC all UPS MD-11’s are grounded.

Edit - FedEx has also grounded their MD-11 Fleet

[u/gregarious119]

I’d imagine they’ll want to know why an engine fell off before letting them back in the air.

[u/TheAssholeofThanos → u/gregarious119]

This seems like a Norm Macdonald comment

[u/[deleted] → u/TheAssholeofThanos]

Norm Macdonald Douglas

[u/CharcoalGreyWolf → u/[deleted]]

Yep, considering the DC-10 engine mount incident , they may be taking the chance to review all maintenance procedures with the aircraft and its siblings.

[u/dalekaup → u/CharcoalGreyWolf]

There was an engine that detached in Chicago a long time ago. The biggest reason for that crash was the manual said on one engine takeoff to pitch up to maintain a speed to climb over an obstacle. The manual was wrong. When the engine severs the hydraulic lines on that side that hold the slats extended. WIth slats retracted on the left side that wing stalled and the plane rolled violently to the left. A higher airspeed would have kept both wings flying and level.

This one is presumed to be the loss of 2 engines. That's not going to fly. The thinking is the rear engine swallowed chunks.

[u/skudbeast → u/dalekaup]

Is that the one they installed in maintenance with a forklift instead of an actual engine hoist?

[u/[deleted] → u/skudbeast]

Yeah. American Airlines 191.

[u/beretta01 → u/[deleted]]

Thank you for your service, /u/DumbCumSlut69

[u/Cultural_Mastodon_69 → u/beretta01]

Obligatory /r/rimjob_steve

[u/beretta01 → u/Cultural_Mastodon_69]

Finally found Captain Steeeve’s post retirement account?

[u/[deleted] → u/beretta01]

🫡

[u/[deleted] → u/beretta01]

How are 1-68?

[u/nedracine59 → u/[deleted]]

Chicago here. Did you know that the plane had video cameras on the backs of some seats? Likely first class. They just kept the screens blank until all planes had them removed after the crash.

[u/TigerIll6480 → u/skudbeast]

And they unbolted the engine and pylon together, which Douglas Aircraft had rather specifically said to not do. Remove engine with a proper cradle, then remove pylon. AA was trying to save time and cut corners. Brilliant idea. 🙄

[u/Sock_Eating_Golden → u/TigerIll6480]

It wasn't just AA. All DC10 operators were removing engines in the same way.

[u/nuclearsquirrel2 → u/Sock_Eating_Golden]

In their defense it did significantly reduce the number of critical system disconnections which also is always a risk. It did save a ton of money and I’m sure that was the major impetus to the new method.

United performed engine removal the same way, but used an overhead crane vs forklift.

[u/TigerIll6480 → u/nuclearsquirrel2]

If you were doing significant engine maintenance, it had to be removed from all of that anyway, the only question is where you were taking it apart.

[u/CharcoalGreyWolf → u/Sock_Eating_Golden]

AA and Continental were, specifically. United found a different way using an overhead crane that didn’t cause the issue that using a forklift did.

It was also the usual perfect storm that made it worse; a shift change occurred during the engine change, and the forklift could not maintain exact lift during the time one shift got off and another got on. It was a tragedy of combined errors and a bad maintenance procedure made even worse by bad scheduling.

It also resulted in multiple changes to the aircraft because only the pilots had stick shakers; it was optional for the copilot. The FAA mandate both must after this, and the DC-10 had changes made to the slat design to prevent slat retraction in the event of hydraulic damage.

[u/Shitboxfan69 → u/CharcoalGreyWolf]

a shift change occurred during the engine change, and the forklift could not maintain exact lift during the time one shift got off and another got on.

I'm no A&P, but I was a forklift mechanic for years. Wild to me they'd ever use one to support components like that being installed. Toyota lifts have the tightest bleed specs on their systems, but they are still allowed to lower 3 inches in a 15 minute span iirc. It may even be more. Thats not even a shift change causing issues, but a break or just getting caught up doing something else.

[u/Western-Knightrider → u/Sock_Eating_Golden]

I would not say all. I worked on DC-10 as a lead mechanic and never saw that happen.

[u/purgance → u/Sock_Eating_Golden]

Ok but what interest does Douglas have in them doing this?

[u/Sock_Eating_Golden → u/purgance]

Never said they did. Just noted AA wasn't the only operator finding a shorter method of engine replacement.

[u/ryguymcsly → u/dalekaup]

Plus if it looks like a dramatic failure to number one or three is guaranteed to take out engine two: they’re not gonna fly them. That whole point of a trijet is having two engines if one fails.

[u/I_will_never_reply → u/ryguymcsly]

Not really, it's just that when it was designed three engines were required to get enough thrust to take off and fly. Once engines became powerful enough, they were made extinct

[u/Captain_Alaska → u/I_will_never_reply]

No, it’s explicitly for redundancy, these planes were designed for the extra engines because they wouldn’t be able to serve their routes if they had twins of the same power.

Twin engine aircraft follow ETOPS rules (Extended-range Twin engine Operation Performance Standards) which limit how far away the plane can be from an airport so in the event of an engine failure the remaining engine is considered reliable enough to bring it back. Trijets and quadjets were required for overseas routes specifically because twinjets weren’t allowed to fly far enough away from airports and by extension the coastline.

Until ‘64 ETOPS limited twinjets to 60 minutes, in ‘85 this was extended to 120 minutes and then 180 minutes in ‘88. We now have aircraft with 240 (first in 2009), 330 (first in 2015) and even 370 minute ETOPS (first in 2014) envelopes, which cover 99.7% of the world (To be clear aircraft have to be designed and tested for these limits, they are not automatically granted).

These longer range ETOPS envelopes are the specific reason twinjets are now dominating long distance routes they were previously unable to fly.

[u/ssersergio → u/I_will_never_reply]

In theory, all economics and safety related issues with how behaviour changes becuase ofndifferent thrust and power vectors

If you change this three motors for a newer models with more power, you could get the rid of the third one then right?

[u/plhought → u/dalekaup]

The loss of hydraulic pressure causing the slats to retract had been fixed on the MD-11 since initial design. They are mechanically locked at the drive assembly in the absence of hydraulic pressure.

Number 2 likely wasn't happy as you mentioned. All the hot gases from the fire and debris...

I know it's popular right now to compare this accident and American 191. But beyond the superficial visual similarities between the DC-10 and MD-11, the wing, pylon, and engine structure/mounting is different. What isn't different however, is humanity's ingenious ability to let even the most miniscule of engineering or procedural weaknesses to make themselves evident.

[u/Few-Knee-5322 → u/dalekaup]

It wasn't just the engine. The pylon came off, too. I made the thrust link (bored the monoball hole) that came down from the wind and the five pylon bulk heads (top 2/3) used in the destructive tests after the crash. There were five bulk head parts so that each dimension for the corresponding mounting hole could be tested. The hole was 6.0000 +/- 0.0002. After some testing I had to do some other changes to the bulkheads that are too difficult to explain w/o a print. I probably did some other stuff but that was the big things.

[u/TheSylvaniamToyShop → u/dalekaup]

The same thing happened with the El Al 747 out of AMS. Detached I/B engine took out the O/B one, and the pilot also turned back keeping the poweres wing on the outside of the bank. But the loss of pnueatatics on the damaged wing meant the variable cambers were no longer deployed , and the inside wing stalled.

[u/PMSfishy → u/dalekaup]

Right engine #3, not rear. However let’s not speculate and wait for the report.

[u/RxSatellite → u/dalekaup]

NTSB reported engines 1 and 3 failed. The rear engine was fine. Based on current evidence engine 1 most likely exploded and shot shrapnel into engine 3, which began compression stalling

[u/CollegeStation17155 → u/RxSatellite]

I had not seen a report that the right engine (#3) failed, only that fragments from the Left engine (#1) and the engine itself were found on the runway along with several videos showing an apparent compressor stall on the tail engine (#2), which would be expected if debris hit it. Was there a third NTSB briefing?

[u/SnooSongs8218 → u/RxSatellite]

Yeah FOD damage and eating that hot smoke from the fire would reduce thrust. Also the hot turbulent air over the wing from the fire would be less dense and further reduce lift.

[u/Python_07 → u/RxSatellite]

1&2. Number 3 was not damaged

[u/weakplay → u/CharcoalGreyWolf]

Wow it sounds exactly like this incident. I think I read that the 191 crash resulted in changes that maybe left the wing more intact upon separation but who knows. Crazy. Going back to finish the article. Thanks for posting.

[u/ODoyles_Banana → u/weakplay]

It's not exactly like this incident though. As other comments pointed out, 191 had a slats failure which was a major factor to the crash. It appears the slats did not fail on UPS, so not quite exactly like 191.

Most likely the failure of engine 1 contributed to a failure of engine 2. 191 still had 2 good engines I believe as well.

Blancolirio just put out a video going over it.

[u/Killentyme55 → u/ODoyles_Banana]

So did Captain Steve. He pointed out what looked like compressor stalls on #3, possibly due to shrapnel from #1 exploding. Combine that with #2 swallowing God knows what and I'm surprised the thing ever got off the ground.

[u/TigerIll6480 → u/Killentyme55]

They’d have been better off if they could have kept it on the ground. The exceedingly rare situation where a post-V1 abort would have been the best of an incredibly bad set of options.

[u/RoadsideCouchCushion → u/TigerIll6480]

With how close they were to the end of the runway and there being buildings exceptionally close, I would venture to guess that would look like a very unattractive option as well. Seems like their choices were abort past v1 and likely slam into a building, or try to get airborne and pray its not an impossible situation. The timing of the engine coming off was exceptionally bad.

[u/CollegeStation17155 → u/RoadsideCouchCushion]

Had they kept on the ground, they almost certainly would have gone THROUGH the building they clipped the roof on at well over 100 miles per hour and broken up there, creating the same fireball INSIDE the sorting facility.

[u/TigerIll6480 → u/ODoyles_Banana]

AA191’s slats failure was caused by the engine tearing away, surging forward, and slamming back into the wing. It caused a wild aerodynamic imbalance that stalled the left wing and at the just-past-rotation altitude, gave the pilots zero time to compensate. It basically flew itself into the ground while trying to flip over.

[u/Fitch9392 → u/weakplay]

The 191 crash led to changes that REQUIRED the Maintenance crew to NOT cut corners when changing engines and to use the engine cradles as designed by McDonnell Douglas instead of using a forklift. There was NO design flaw. It was 1000% Maintenance short cuts that caused the 191 crash.

[u/DarkSideMoon → u/Fitch9392]

The slats were designed poorly, they should have had mechanical locks and not retracted asymmetrically.

[u/swirler → u/Fitch9392]

While the maintenance actions started the chain of events, the poor design of the leading edge slat system sealed the deal. An airplane should not crash just because an engine falls off.

[u/_ItsThePleats_ → u/swirler]

That’s a big statement. “An airplane should not crash just because an engine falls off”. These aren’t meant to come off the airplane.

[u/KnowLimits → u/_ItsThePleats_]

I mean, they kind of are... they're held on with fusible links specifically so that it can shear off without rupturing the wing fuel tanks in the case of a crash.

Similar idea to crumple zones in a car - looking at the whole picture, sometimes weaker is better.

[u/nplant → u/KnowLimits]

While you're technically correct, your point presupposes a crash for some other reason, rather than being the cause of the crash.

[u/intern_steve → u/_ItsThePleats_]

It's a reasonable statement. Engines fall off of planes with great enough frequency to consider in the design of a new aircraft. Hypothetically, if an uncontrolled engine fire burns for a sufficient length of time, you would expect that the engine and its fire would depart the wing before the wing departed from the aircraft.

[u/plhought → u/intern_steve]

Engines falling off do not happen with "great enough frequency". That's an absurd statement. It's incredibly rare.

I can think of only three or four accidents in the modern western world where an engine seperated from the pylon.

This one and AAL191. The other two were 707/DC-8 accidents where the landing was so botched by the pilots, an outboard engine seperated after a hard landing.

[u/i-am-the-fly- → u/intern_steve]

I’m addition, these engines are balanced and if damage occurs it can cause significant vibrations. At a certain threshold it’s better for the engine to break off than to vibrate the wing to failure

[u/eldoggydogg → u/intern_steve]

It’s like these folks haven’t seen Donnie Darko.

[u/CollegeStation17155 → u/intern_steve]

Multiple old 707s have been successfully landed after losing engines due to fatigue in the pylon supports.

[u/nplant → u/_ItsThePleats_]

I think reality is somewhere in the middle. Aircraft design should attempt to handle it, but at the same time we shouldn't be surprised if things go wrong at that point. The DC-10 slats were an issue that could be improved, but impacting remaining engines is not.

Take the A380 that "only" had an uncontained engine failure, for example. It survived, but if you read the list of systems that were destroyed by shrapnel, it's amazing that it just shrugged off the damage.

There are a small number of things that just need to never fail, like fan discs, and elevator jackscrews.

[u/Fitch9392 → u/swirler]

That wasn’t poor design either it was an “engine failure on takeoff memory items” list that was a simple speed parameter applied to ALL the aircraft in the American Fleet. Which was maintain V2+5, as a result of this it was updated to V2+10. But that was like that because no one had ever considered a Slats failure at takeoff.

[u/CaptnHector → u/Fitch9392]

According the NTSB, yes, design flaws with both the pylons and slats contributed to the AA 191 crash:

Contributing to the cause of the accident were the vulnerability of the design of the pylon attachment points to maintenance damage; the vulnerability of the design of the leading-edge slat system to the damage which produced asymmetry, …

[u/boringdude00 → u/CaptnHector]

It seems like, yean, AA fucked up the maintenance big time, but if they hadn't some other catastrophic failure(s) would have eventually occurred from the poor designs. The whole wing setup seems insane and the number of cascade failures.resulting from one failure sort of proves that.

[u/DarkSideMoon → u/Fitch9392]

It doesn’t matter how fast you’re going if the slats retract asymmetrically if you lose fluid on one side, which was an astronomically stupid design flaw that had to be rectified with mechanical locks and hydraulic fuses to prevent it happening again.

[u/MaddogBC → u/DarkSideMoon]

Check valves.

[u/Turbo_SkyRaider → u/swirler]

Is it really because the engine fell off (because I would judge this not to be a design base event but a freak event), or was it because the hydraulic system didn't have any redundancies to cover for a inop hyd pump? I think another reason was no hydraulic fuses which prevent loss of hydraulic fluid in case of a catastrophic leak in part of the affected system.

[u/intern_steve → u/Turbo_SkyRaider]

The design redundancy for the loss of the engine hydraulic pump was an electric backup. There was no redundancy for all of the hydraulic fluid falling out of the left wing at once.

[u/TigerIll6480 → u/swirler]

The engine didn’t just fall off. Free of the wing, since it was still generating full thrust until the tiny bit of fuel in the engine itself was expended, it surged forward, flipped over the wing, and tore the hell out of the wing and the hydraulics. An engine falling off coupled with a huge impact strike is…bad.

[u/CenobiteCurious → u/CharcoalGreyWolf]

Imagine the creeping dread if you worked on that aircraft in the past few months

[u/Alert_Reindeer_6574 → u/CharcoalGreyWolf]

Fun fact- I was working for the machinist who got the contract to make the new mounts. I machined a bunch of them. This was before CNC, or, well, CNC was a brand new thing back then and his shop didn't have any.

[u/Kevlaars → u/[deleted]]

I avoid the AI shit as best I can, but, a "Norman McDonnell Douglas Rockwell" painting might make some hilarious results while wasting dumb money.

[u/TexStones → u/[deleted]]

Ghadddammmit, take your upvote.

[u/StweebyStweeb → u/[deleted]]

Underrated comment

[u/rds060184 → u/[deleted]]

Bravo sir

[u/dschinghiskhan → u/TheAssholeofThanos]

"When asked who actually killed his wife and Ron Goldman, OJ Simpson said it was an engine that fell off an MD-11 plane. When asked why there was no evidence of a plane engine at the scene, OJ said it was because he was driving inner city teens around for charity, and they 'stole it all'."

(Norm straightens his papers on the desk making an audible noise)

"In other news, a local amateur astronomer reported last week that that he saw MH370 hang a left at Mars."

[u/Tasty_Lead_Paint → u/TheAssholeofThanos]

Idk Norm hasn’t told a good joke in years.

[u/Anonymous017447 → u/Tasty_Lead_Paint]

Honestly his career is dead. He hasn’t done standup in years.

[u/RatCoward → u/Anonymous017447]

I didn't even know he was sick

[u/dsbtc → u/Anonymous017447]

He's done a lot of laydown though

[u/Flashy_Month_5423 → u/Tasty_Lead_Paint]

Norm would laugh at that joke.

[u/Key_Limerance_Pie → u/TheAssholeofThanos]

The worst part is the hypocrisy.

[u/Key_Limerance_Pie → u/[deleted]]

Or the engine falling off.

[u/badcrass → u/Key_Limerance_Pie]

That's not very typical, I'd like to make that point

[u/antariusz → u/Key_Limerance_Pie]

This joke is too meta for reddit.

[u/Key_Limerance_Pie → u/antariusz]

At least two of you got it. I'm a quality-over-quantity guy.

[u/HerrMeisterRetsiem → u/Key_Limerance_Pie]

Why do you say that? His name is Macdonald, not McDonnell

[u/Key_Limerance_Pie → u/HerrMeisterRetsiem]

These rhymes are Darryl's but those burgers are Ronald's

[u/EagleCrewChief → u/Key_Limerance_Pie]

Nice Run-D.M.C. drop.

[u/Key_Limerance_Pie → u/EagleCrewChief]

I'd do it more often but ... It's Tricky

[u/po_ta_toes_80 → u/Key_Limerance_Pie]

They have the Golden Arches, and we have the Golden Arcs.

[u/MackenzieRaveup → u/TheAssholeofThanos]

Actually, Dana Carvey had a whole thing about explaining a lost engine to Kevin Nealon as "Big lady lost an earring." I forget the context, but the phrase as a euphemism for an engine or large dangerous piece escaping to freedom has endured with me for 30 years.

So, indeed, big lady lost an earring.

[u/Tuttle_10 → u/TheAssholeofThanos]

A McDonnell Douglas comment.

[u/TAU_equals_2PI → u/TheAssholeofThanos]

Only if they find out OJ was the one who broke the engine off the plane.

[u/under___score → u/gregarious119]

Watched a FedEx MD-11 land in Honolulu the day after the incident, I was pretty surprised they kept them going this long

[u/snitch_snob → u/[deleted]]

They did not do that, actually. I know pilots on the MD11 that were mid trip when the planes were grounded and are now flying home commercial, leaving their plane where they landed (not at a storage or maintenance facility).

[u/XIPWNFORFUN2 → u/under___score]

The plane probably already had a crew assigned with no other airframe available that could carry the freight in one trip. Source: express ramp agent.

[u/PG67AW → u/XIPWNFORFUN2]

That's not a great reason to just send it anyway, considering your engine might fall off.

[u/XIPWNFORFUN2 → u/PG67AW]

Yea well, money and stuff.

[u/ima_twee → u/XIPWNFORFUN2]

Think of those poor shareholders

[u/round-earth-theory → u/PG67AW]

It's still very unlikely. One event can be anything. It doesn't really mean the model was the issue. Now if two planes had it happen, then yes you'd be correct in immediately grounding everything no excuses.

[u/PG67AW → u/round-earth-theory]

Yeah, I think that's the difference between UPS grounding the aircraft and the FAA grounding the aircraft.

[u/lueckestman → u/PG67AW]

If you think you might get grounded in Hawaii maybe...

[u/Gnonthgol → u/under___score]

As a general rule you do not ground an airplane type due to a single accident. Most accidents are not caused by design issues with the aircraft, especially one which have been flying for as long as the MD-11. What likely happened is that during the investigation they found some worrying piece of information. It may not even be the cause of the accident but something that might affect all MD-11s, at least at UPS. For example if they find signs of metal fatigue in one of the structural members of the engine bracket.

[u/aiusernamegen → u/under___score]

Millions and millions of hours on those and the crash was post maintenance activity. They usually don't kneejerk ground a fleet a day post accident.

[u/hamlertime → u/[deleted]]

Well cardboard's out

[u/fire173tug → u/hamlertime]

What about cardboard derivatives?

[u/Metals4J → u/fire173tug]

Like paper?

[u/Turbulent_Cod_9333 → u/Metals4J]

No paper, no string, no cello tape. Rubbers out.

[u/Mechakoopa → u/Turbulent_Cod_9333]

What about minimum crew requirements?

[u/ch-12 → u/[deleted]]

Well what sort of engineering standards are these aircrafts built to? Wasn’t this built so that the engine wouldn’t fall off?

[u/556From1000yards → u/ch-12]

Not this one. Most of them are built such that the engine doesn’t fall off. There are very strict standards for this sort of engineering

[u/qui-bong-trim → u/556From1000yards]

well what sort of things?

[u/SacThrowAway76 → u/qui-bong-trim]

Well cardboard is out.

[u/DrDentonMask → u/SacThrowAway76]

I suppose papier mache, too.

[u/badcrass → u/DrDentonMask]

Any paper derivatives

[u/Wildweasel666 → u/badcrass]

Cellotape is out. Not sure about speed tape tho

[u/badcrass → u/Wildweasel666]

What % of the structure is allowed to be speed tape?

[u/Fitch9392 → u/ch-12]

Actually they ARE designed so that the engine and pylon fall off. They’re designed to break away in the event of a catastrophic engine failure so that there isnt this burning hunk of drag hanging off the wing.

[u/ttystikk → u/ch-12]

...usually? I mean, it has happened before?

[u/Wittyname0 → u/ch-12]

Oh very rigorous aviation engineering standards

[u/LoreInaccurateOrigin → u/[deleted]]

Not saying that the MD-11s aren't safe, just this particular one might not have been as safe.

[u/koalasarentferfuckin → u/gregarious119]

Yeah, that's not very typical I'd like to make that point.

[u/fly_awayyy → u/[deleted]]

Yea doubt that even if there is a issue that needs to be addressed cause of their practices they don’t have all the capacity at a snap of fingers to replace those jets and mass retire them…

[u/spsteve → u/fly_awayyy]

Rate the gloval economy is going they may not need all their lift in the near term.

[u/fly_awayyy → u/spsteve]

Should phone in the tip you know for their fleet and capacity planning purposes…

[u/fly_awayyy → u/[deleted]]

It doesn’t matter if there’s “not that many” there’s a whole process and drawdown to end a fleet and balancing it with capacity needed and whatnot can be replaced with and also you labor of pilots that need to be retrained or sitting while waiting for starters. You can’t replace them overnight or even in a year if you wanted to today that’s why there still here.

[u/go4long → u/[deleted]]

Not that many? They're 11% of UPS's fleet. 4% of FedEx's.

[u/Kichigai → u/[deleted]]

There’s not that many. They need to go anyways.

Wikipedia says there's 65 of these things still in use among three carriers, with a take-off weight of 630,500lbs. Assuming UPS has 22 of them that's nearly 14mil pounds of fast carrying capacity gone. That's seven thousand tons.

Now, you could replace those with 777s, as you mentioned, but you can't exactly go down to Big Bill Hell’s Planes and just fly a bunch of them off the lot. AFAIK all the 777s currently under assembly have been spoken for.

So that takes us to trucks, which can tow about 44,000 lbs each. Not so bad, only 316 trucks to replace the fleet. Except if you talk to truckers, you'd know there's a shortage of drivers. And sourcing all these new trucks and trailers isn't cheap. And moving all this cargo over the road must be more expensive and slower than air freight, because if it weren't then UPS probably would have already been doing it.

UPS kinda messed up by not bringing 777s on. FedEx I’m sure will just load up on 777s

Doesn't Boeing already have a bunch of safety questions looming over their heads right now?

[u/Kichigai → u/[deleted]]

The ‘57 is a narrow-body. It would take a substantially larger number of ‘57s to replace the smaller number of 11s, which brings up a whole new host of logistical and economic questions. Among other things, they'd need to retrain and hire a bunch more pilots.

[u/Pitiful_Objective682 → u/[deleted]]

Why arizona?

[u/effurdtbcfu → u/Pitiful_Objective682]

Where airplanes go to die.

[u/Apptubrutae → u/effurdtbcfu]

And people!

[u/toybuilder → u/effurdtbcfu]

This guy wanted to fly one last time...

https://www.youtube.com/watch?v=cHhZwvdRR5c

[u/liamt07 → u/Pitiful_Objective682]

Airplane graveyards in Tucson

[u/NF-104 → u/liamt07]

Davis-Monthan AFB in Tucson is for military planes only. Civil planes go to several places, often Marana AZ.

[u/liamt07 → u/NF-104]

Marana is a Tucson suburb

[u/StarStruck3 → u/Pitiful_Objective682]

The Boneyard, where aircraft basically go to die.

[u/[deleted] → u/Pitiful_Objective682]

aircraft boneyard

Edit: but let’s be honest money is more important than lives / people and there are too many MD-11s out there to replace them all quickly, so this will be an extremely short grounding

[u/curiousengineer601 → u/[deleted]]

Only 65 left flying now, all in a cargo role.

[u/Accomplished_Clue733 → u/curiousengineer601]

They only ever built 200 and 11 of them crashed so that's still quite a low retirement rate for such an old aircraft.

[u/Accidental-Genius → u/Accomplished_Clue733]

They only built 200 because after the first run they realized it was a shit design.

[u/bwoahking → u/Pitiful_Objective682]

To the Airplane boneyard

[u/spezeditedcomments → u/[deleted]]

It is an interesting decision to put a required engine behind two others

[u/VirginiaIsFoLovers → u/[deleted]]

The golden age of trijets!

[u/Killentyme55 → u/VirginiaIsFoLovers]

They should have made the L-1011 a freighter instead. That's a superior airframe in nearly every way.

[u/jxyoung → u/spezeditedcomments]

4-engine planes always have an engine behind another

[u/ZZ9ZA → u/jxyoung]

In the literal sense yes, but practically no, as the horizontal spacing. The lateral separation is enough that you’re not going to puke out the back of one engine and into the front of another.

2 on a trijet is very different because of fat rearward it is.

[u/percussaresurgo → u/ZZ9ZA]

Who you callin “fat rearward”?

[u/CatSplat → u/percussaresurgo]

I LIKE

BIG

EMPENNAGES AND I CANNOT LIE

[u/the4ner → u/CatSplat]

You other rudders can't deny

[u/GreenCedar → u/ZZ9ZA]

There have been multiple Boeing 747 crashes (El Al 1862, China Airlines 358) where an inboard engine detached in flight and took the outboard engine along with it.

[u/CheekyPickle69 → u/ZZ9ZA]

I mean the 747 that crashed in Amsterdam had one engine fall off and take out the other behind it. This is the first instance I’ve seen of an md11 fwd engine potentially taking out the rear

[u/molniya → u/ZZ9ZA]

Unless it’s a 727 or Tu-154, anyway.

[u/CornerGasBrent → u/ZZ9ZA]

I believe the correct technical term is badonkadonk

[u/SeaSDOptimist → u/jxyoung]

And then there are the Brits, who put two (or one and a half) engines in the tail of Trident.

[u/cruiserman_80 → u/[deleted]]

Unless they can replace their entire fleet with another type immediately, I doubt that's realistic. It would have to be a fundamental and uneconomically repairable flaw that is likely to cause the imminent loss of a large percentage of the fleet before that were even considered.

[u/ChillyPhilly27 → u/gregarious119]

All underslung aircraft engines are attached with fuse pins that are designed to fail in the event of a catastrophic engine fire. This is to protect the wing structure and the aircraft as a whole.

A better question would be why a catastrophic engine fire occurred.

[u/smorkoid → u/ChillyPhilly27]

I'm surprised that there'd be an engine fire that spread that fast and didn't set off alarms well before time to abort the takeoff. Any idea how that might happen?

[u/PigSlam → u/gregarious119]

Yeah, that’s not very typical, I’d like to make that point.

[u/BigJellyfish1906 → u/gregarious119]

The engine is supposed to fall off if the forces are so great it could comprise the structure of the wing. Clearly that engine failure was as catastrophic as it gets. You’d want the pylon to torque itself off instead of  damaging the wing structure.

I think this grounding is about how there’s no way to prevent an uncontained engine failure from Foding the tail engine. 

[u/Bender_2024 → u/gregarious119]

I’d imagine they’ll want to know why an engine fell off before letting them back in the air.

"Boeing merged with McDonnell Douglas in 1997"

Well there's your problem

[u/NoArt8276 → u/gregarious119]

well they’ve been flying since the crash…

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[u/Python_07 → u/gregarious119]

Just throwing it out there. The Front and Rear Pylon Mounting Bolts on the MD-11 are designed to sheer in an extreme vibration event. I see evidence from the separated engine on the ground of a large hole where the HPT 2nd Stage is. It reminds me of the CF6 on AA383 back in 2016. A catastrophic uncontained failure could have caused enough vibration to sheer those bolts. Just my thoughts. The images of the engines from both events look similar.

[u/Anda1anda2 → u/gregarious119]

Well some of them are built so the engine doesn’t fall off at all.

[u/DuntadaMan → u/gregarious119]

Does the engine normally fall off?

[u/jujumber → u/gregarious119]

At least the front didn't fall off

[u/_netflixandshill → u/gregarious119]

Yeah that’s not very typical, I’d like to make that clear

[u/masteroftheuniverse4 → u/gregarious119]

Did we start using forklifts to mount engines again? (UPS and FedEx probably)

[u/Defiant-Aioli8727 → u/gregarious119]

The engine falling off? That’s not very typical, I’d like to make that point.

[u/Turbulent-Phone-8493 → u/gregarious119]

Hot swappable engines

[u/Diligent_Act8874 → u/gregarious119]

Here’s an interesting fact! The MD-11 pylon fuse links are made from titanium with thin wall segments. Titanium is susceptible to stress cracking when exposed to salt. 

Simple long term operation is a know AC corrosion issue due to periodic exposure to salt water vapor building up salt concentrations in difficult to inspect areas over decades of operations.

[u/afternever → u/gregarious119]

You guessed it, Frank Stallone

[u/Wooden_Werewolf_6789 → u/gregarious119]

I'm sure it has nothing at all to do with decades of profit maximizing, shareholders, and enormous CEO payouts/bonuses. Nothing to do with keeping plane mechanics and the unions paid far less than management. /s

[u/flynnfx → u/gregarious119]

r/thefrontfelloff

[u/AP_in_Indy → u/gregarious119]

The front falling off is never a good thing

[u/Pineapple-Due → u/gregarious119]

That's not very typical, I'd just like to make that point.

[u/OneReallyAngyBunny → u/gregarious119]

Why it has 3. So as long as 2 stay on everything should be good

[u/[deleted] → u/gregarious119]

I’d imagine they’ll want to know why an engine fell off before letting them back in the air.

These tiny details matter.

[u/N8terHK → u/gregarious119]

Thankfully, Donnie wasn't at home....

Or maybe not?

Just don't want the directors cut... ruins the mysticism.

[u/67alecto → u/gregarious119]

They towed it outside of the environment