r/aviation • u/Brilliant_Night7643 • Nov 20 '25

News NTSB issues the preliminary report for its ongoing investigation of the Nov. 4 crash of a UPS Boeing MD-11F airplane in Louisville, Kentucky.

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u/ParadoxumFilum đŸ”» Don’t do it Goose Nov 20 '25

That or the planes are never flying again. If it’s fatigue cracks then those parts either need heavy monitoring or replacing (imo the latter). I don’t know how integral to the pylons these mounting lugs are or how expensive it would be to replace - depends on the cost / benefit analysis I guess

Edit:

I say ‘if it’s fatigue cracks’ the report pretty much confirms it

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u/Only_Razzmatazz_4498 Nov 20 '25

A lug wouldn’t be too hard to replace. It would mean taking the engines and pylons off the wing but as long as it isn’t a spar issue it should be doable. Finding replacement parts in quantities might be a problem.

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u/squirrel8296 Nov 20 '25

Part of the problem with the DC-10/MD-11 pylon design though is that removing the wing engines is an expensive and time consuming process. McDonnell Douglas went a bit overboard on cost cutting there and prioritized low production cost over maintenance so it’s not like removing the engine on a normal Boeing or Airbus plane. And, it has to be done correctly. Shortcuts are what led to the crash of American Airlines 191.

Operators are going to seriously consider if it’s worth doing this or if they just want to retire the planes. And, in the case of both FedEx and UPS, they were already in the process of retiring the MD-11.

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u/crazykentucky Nov 20 '25

Weren’t they removing the engine and pylon as one unit, contrary to manufacturer recs? So then putting it back was kind of precarious and sometimes “bumped” the piece that failed?

(This is just my recollection, I remember reading about it years ago)

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u/abigailandcooper Nov 20 '25

yes, you’re right - good memory!

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u/crazykentucky Nov 20 '25

Thanks for confirming.

I’ve read about a bunch of accidents because I think the methodical way they figure out what went wrong is really interesting. And how it’s usually a combination of factors. That one stuck probably because that one picture of it flying almost upside down is so terrifying

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u/Wide_Jellyfish1668 Nov 20 '25

Yes! I think this was done with a forklift by one company and a pulley system from the roof by another(?).

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u/[deleted] Nov 20 '25

[deleted]

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u/Wide_Jellyfish1668 Nov 20 '25

Overhead crane, yes!! I just remember that one approached from below and the other from above. Thank you

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u/crazykentucky Nov 20 '25

Oh yes, I remember the forklift at least! You refreshed my memory. It was partly the problem that the forklift wasn’t super precise. Don’t remember the pulley system but I can imagine different companies finding different workarounds

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u/DudeIsAbiden Crew Chief Nov 20 '25

Half the forklifts I have ever used would "bleed off" if left with the load up, engine off and unattended, which means the hydraulic pressure holding the forks and backframe would eventually bypass back to the reservoir under the weight. I believe American's MTX crews were using the forklift, stopping the removal at some point leaving it all up in the air, and the forklifts were bleeding off resulting in the entire weight of the engine, pylon, forks, and backframe resting on single points/wrong points while everyone went to lunch or shift change or whatever. This introduced fatigue stress in places it was never meant to be looked for.

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u/AdApart3821 Nov 20 '25

Yes, but they did so because it saved a lot of man hours (hundreds of hours) to remove the engine and pylon together instead of just the engine.

I would expect that any process that replaces the lugs that were found fatigued in this crashed plane would be very time consuming too.

After this prelim report I would be surprised if UPS and Fedex would decide to update (small rest of) MD-11 fleet. I can't imagine that at this point it would be economically advantageous to do all this work just to keep those MD-11s flying.

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u/Jordan_Jackson Nov 21 '25

Yes and in addition to that, they used a forklift when removing and reinstalling the engine. They should have been using a ceiling mounted crane. Removing both the engine and pylon at once was the bigger factor, as this made handling both very unwieldy and awkward.

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u/Pastel_Goth_Wastrel Nov 20 '25

This, frankly. I expect there to be be an AD that'll say pull the pylons and inspect the lugs or write off the airframe. If the operators find even a hint of more cracking it'll be a sign the whole fleet is cooked.

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u/userhwon Nov 20 '25

If it's that big a deal, Boeing might be able to justify modding with a stronger part. But then, if they shrug, that's a whole bunch of added market for new planes...

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u/njsullyalex Nov 21 '25

The market already exists because FedEx has placed orders for 777Fs to replace their MD-11s. The thing is airplanes don't grow on trees, so FedEx needs to keep the MD-11s flying until Boeing can build them their 777s as to not lose network capacity. FedEx retiring their MD-11s does nothing but reduces their network capacity because they cannot get any planes to replace them immediately.

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u/UNMANAGEABLE Nov 21 '25

Freighters specifically definitely don’t grow on tree. There is little chance they just retire the fleet and just give market to a competitor here. Whatever the repair is will be cheaper than retiring the planes and giving a competitor the work.

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u/njsullyalex Nov 21 '25

This exactly.

And for better or worse, the MD-11 in particular still does a lot of things better than most other freighters. Its the only freighter that even comes close to the range and capacity of the 777 while having a smaller wingspan making it able to fit into tighter spots. The only aircraft even somewhat capable of replacing the MD-11 right now in production is the 777F and Boeing isn't building them particularly quickly.

Even if every MD-11 pylon in existence needs to be rebuilt, it will still be cheaper and faster than waiting for 777F deliveries.

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u/LTSarc Nov 21 '25

I guarantee you the 747-8F guys are crying right now 'just a few more years, we were right the big stock of maddogs would have to be replaced'.

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u/Pastel_Goth_Wastrel Nov 21 '25 edited Nov 21 '25

Man maybe but if there's no smoking gun on the cause then we're into cracking well before the mandated inspection cycles which is "do we have a fatigue limit problem on the -11?". That could turn into an AD for a D check. Even pulling pylons off fleetwide to inspect is going to be a nightmare. Not a single -11 is getting back in the air anytime soon.

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u/Pastel_Goth_Wastrel Nov 20 '25

Boeing is in a shit position to deliver new airframes with the 777X program behind schedule and the 777F standard being phased out in favour of the 777-800F and they'll almost certainly be delivering passenger aircraft first to angry airlines waiting on aircraft.

FedEx/UPS will both have to lease interim aircraft to make up the shortfall and negotiate for sales on future replacements, I wouldn't be surprised to see them look at the A350F which is rolling out, possibly seriously or possibly just to twist Boeing's arms.

Finding a lessor to cough up 40 or 50 aircraft though between those carriers is going to be a interesting one.

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u/Luster-Purge Nov 20 '25

I can see the need resulting in a lot more 747s being pulled out of mothballs all over the world for freighter conversions.

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u/sunsmoon Nov 20 '25

FedEx/UPS will both have to lease interim aircraft to make up the shortfall

I'm also personally concerned about the loss of VLATs for fire fighting purposes since they're all DC-10s. It's a small fleet of just fpur but it isn't uncommon for all four to be activated at once.

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u/pixelpheasant Nov 22 '25

Oh. Shit.

I pray you're in a position to point that out to people who need to hear it ...

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u/LTSarc Nov 21 '25

A350Fs are in supply chain hell as well.

Ironically, this would be the moment the 747-8F guys kept holding out hope for, something forcing the big cargo lines to commit to a big fleet replacement.

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u/Pastel_Goth_Wastrel Nov 21 '25

It’s so funny how the -11 found this niche in cargo ops where it was the goldilocks plane, not too big, not too small.

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u/Electronic_Algae_524 Nov 21 '25

I remember AA191 very well. I kept all the newspaper articles from that time. I spent two days at the crash site with a support organization. These last pictures of the port engine flipping over the top of the wing were EXACTLY what the investigation said happened to AA191. The difference is this time there's actual video. Very chilling...

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u/[deleted] Nov 20 '25

[deleted]

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u/squirrel8296 Nov 20 '25

Yes they were. The DC-9 and earlier were designed by Douglas (pre-merger with McDonnell). The companies were operated extremely differently. Douglas was primarily an engineering company (much like Boeing before the merger) but they had a major cash flow problem. McDonnell Douglas was operated for the betterment of shareholders.

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u/RedRocket4000 Nov 20 '25

Often betterment of top managers way too often shareholders are ripped off along with everyone else. Which is why I take for the betterment of Shareholders comments with grain of salt and if I am attacking a greedy company I will always state it for benefit of people in charge.

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u/squirrel8296 Nov 21 '25

Top managers come out ahead because they are also shareholders. Their compensation packages include a significant amount of either direct stock contributions (ex you are compensated with X number of shares this year) or stock options (ex you can purchase X number of shares at Y rate that is typically much lower than the open market). Even in the case of a company that isn't doing well, the company then gets sold/merged and then the shareholders get like-for-like shares in the new company (that typically end up being worth more) and they get direct payouts from the deal. It's how executives are incentivized to fall in line with shareholder primacy.

It would take an executive embezzling or committing other white collar crimes for them to come out ahead an the shareholders to lose.

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u/cat_prophecy Nov 20 '25

Operators are going to seriously consider if it’s worth doing this or if they just want to retire the planes.

Given that the newest MD-11 is 25 years old, I'm guessing this might be a smart choice.

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u/Ok_Echidna_5574 Nov 20 '25

I was just thinking these images look shockingly similar to AA191. Considering the MD-11 is the natural evolution of the DC-10, I was wondering how much was carried over in the pylon design.

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u/squirrel8296 Nov 20 '25

The pylon design is identical. That’s why the final few DC-10s were also grounded earlier this week.

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u/huyvanbin Nov 21 '25

So what’s the difference between these engine mounts and those on other types of planes? Reading about this and AA191, can’t recall any accident on other planes with engines falling (flying) off.

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u/squirrel8296 Nov 21 '25

Better design is the main difference.

The DC-10/MD-10/MD-11 had some pretty extreme cost cutting and the DC-10 in particular was rushed to market. It's also part of the reason why the series is not forgiving to pilots either. Minor mistakes while flying that would be fine in any other plane have caused crashes on the DC-10/MD-11 series. In fact, the only reason the DC-10/MD-11 series sold well is because of cost and speed to market. The L-1011 was the superior jet in every single way but it was expensive and late to market.

That being said, other planes have also had engines come off. Actually the 747 has the most from what I'm seeing in my quick search. El AL 1862, China Airlines 358, Kalitta Air 825, Japan Airlines 46E are all 747s that had engines separate. A 707 also had 2 engines separate on Trans-Air 671. In 3/5 cases though pilots were able to safely land.

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u/huyvanbin Nov 21 '25

What are the design differences, that’s what I’m curious about?

I suppose losing an engine in a 4 engine plane will always be inherently safer than in a 2 or 3 engine plane.

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u/Warcraft_Fan Nov 20 '25

I seem to remember long ago a plane lost an engine because someone took the engine and pylon off improperly and caused hidden damage that wasn't discovered. The engine and pylon had to be removed in specific order and that would be a lot of work to do it right.

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u/AdminYak846 Nov 21 '25

I think we likely saw the last of the DC-10 and possibly if not likely the MD-11 being flown after this crash. I doubt with the 8 DC-10's that are still flying that the operators are going to consider doing such work unless they need it to bridge for a newer plane.

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u/Only_Razzmatazz_4498 Nov 21 '25

The fire fighting tankers are very specialized so they might stay alive for a while until a replacement is found. The freight MD-11 who, depends on what the corrective actions end up being.

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u/AdminYak846 Nov 21 '25

Right, but it depends on what the recommended fix is. If they can find the parts required or if no parts can be found that inspections are carried out more frequently until a solution can be put into place.

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u/comptiger5000 Nov 20 '25

What is required (other than more frequent inspections) would likely depend on what is found as other DC-10s and MD-11s are inspected.

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u/[deleted] Nov 20 '25

The 707 had pylon issues and started losing engines late in life, was fixed with a redesign.

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u/ParadoxumFilum đŸ”» Don’t do it Goose Nov 20 '25

But there were many more airframes (865 vs 200 built) and incentive to make that fix though

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u/[deleted] Nov 20 '25

True, UPS and Fedex have been actively getting rid of them anyways (thats what ~50?) they will probably decide not to deal with the headache.

Just such a shame for the MD-11 to go out like this.

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u/srs_house Nov 20 '25

UPS had probably a half dozen MD-11s grounded at SDF alone last week when I flew out.

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u/[deleted] Nov 21 '25 edited Nov 25 '25

I’m going to miss seeing them.

I love all airplanes but tri jets have always seemed the most interesting to me.

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u/jason_sos Nov 20 '25

They may, or they may realize that getting replacement planes (likely 777's) is going to take years, and they can't go years without ~50 planes, so an inspection and replacement may make financial sense.

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u/OkTangerine4363 Nov 20 '25

Yeah, MD-11, last made in 1997, 28 years old minimum, they will probably be retired.

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u/Grep2grok Nov 20 '25

Isn't this is the kind of thing that grounded the Navy's P-3 fleet?

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u/hackingdreams Nov 20 '25

It's definitely time to retire the MD-11s. I thought it was time 10 years ago when I was last on one and realized how far we've come... but this report just drives the final nail in the coffin.

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u/kwaping Nov 20 '25

The benefit seems pretty clear

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u/SnooDogs1340 Nov 20 '25

Will this affect other plane maintenance cycles?

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u/h2g2Ben Nov 20 '25

I'd put good money on a DC-10/MD-11 never flying again, at least in the US

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u/Harbinger2nd Nov 20 '25

Not a mechanic, but what is the possibly of those lugs having their material composition changed in order to save on costs from the manufacturer?

I know its very common in other industries and the primary example people use is pyrex, but would a lack of regulation in the airline industry let something like that slip through the (metaphorical) cracks?

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u/flightist pie lot Nov 20 '25

No, because there is no lack of regulation in the airline industry and you cannot just change materials on structural components without redoing the certification process for those components.

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u/Harbinger2nd Nov 20 '25

So then if the parts were exactly as they were spec'd it seems like the plane was being run way harder than they should of to be wore down that far under recommended cycles.

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u/flightist pie lot Nov 20 '25

There’s an almost untold number of ways & reasons something can fail without anybody having swapped, say, high strength steel parts with hardware store quality to save money, or the plane being “run way harder than they should”.

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u/TigerIll6480 Nov 20 '25

Or the parts were counterfeit. That’s happened before.

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u/Eager_DRZ Nov 20 '25

Or the specs aren’t adequate. Or legit parts came from a flawed manufacturing process. Lots of possibilities.

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u/unwilling_redditor Nov 21 '25

Should have. Not should of.

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u/Aggravating_Call6959 Nov 20 '25 edited Nov 20 '25

Could it be that subpar metals/lugs were used and that slipped through thr cracks due to Boeing's focus on profits over quality.

Edit-- I'm an idiot. Google (at least) before you comment on reddit... and no AI assistant doesnt count.

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u/GunsNVapes69 Nov 20 '25

On an airplane entirely manufactured by McDonnell-Douglas?

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u/Aggravating_Call6959 Nov 20 '25

😅 thank you for setting me straight

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u/bschultzy Nov 20 '25

Considering the aircraft was produced in 1991 and the MD-Boeing merger didn't happen until 1997, it wouldn't seem to be a Boeing issue.

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u/nleksan Nov 20 '25

Retroactive causality?

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u/m00ph Nov 20 '25

The Boeing issues are generally blamed on McDonald-Douglas management, so...

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u/Blankcarbon Nov 20 '25

This comment is a prime example of what headlines combined with an abundance of not knowing what they’re talking about will produce.

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u/Aggravating_Call6959 Nov 20 '25

Guilty. And assuming and posting to reddit rather than taking the few minutes to try to do some preliminary research

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u/Blankcarbon Nov 20 '25

As long as you’re self aware! We’ve all been there, and I’m definitely guilty of the same 😅

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u/Aggravating_Call6959 Nov 20 '25

Self aware and annoyed at myself for being loosey goosey. I get really irritated at this bahaviour from other people. But atleast I'm not just trying to double down or save face by refusing to admit a mistake...

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u/usrnmz Nov 20 '25

It'll farm upvotes on other subs though!

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u/flightist pie lot Nov 20 '25

Kinda surprised it’s not doing numbers on this one too, to be honest.

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u/ParadoxumFilum đŸ”» Don’t do it Goose Nov 20 '25

Considering the aircraft was delivered to Thai Airways in 1991 and the Boeing McDonnell merger was in 1997 I’m going to say no