UPS MD-11 Crashes on Takeoff

[fdcg27]

None of the incidents listed on the F28 wikipedia page are mechanical failures (other than one that was a blown tire). Seems a remarkably safe plane under that criteria. Regional jet pilots may not be very good though.

There are many things inherent to a type that can lead to accidents. Actual mechanical failure is only one of those things and is pretty rare for all types, although this appears to have been the cause of this MD-11 accident.
Just looking at hull loss figures the F-28 does stand out and is among the worst.

 

[Albin]

Another video on the recently released NTSB report, this time from one of my favorite aircraft/pilot YTers. I'm only 3 minutes in, so have no idea his final conclusions.

 

[MolaKule]

As usual, the lead-in at about 0.09 by the media got it wrong. Boeing was not the manufacturer, Douglas Aircraft was the manufacturer but inherited the aircraft after acquiring MDC. This was clarified later in the video.

At 16:25 he makes an incorrect comment about a "tongue-and-groove" design.

The race's "groove" is there to act as grease entrainment.

There is no tongue on the spherical bearing. A tongue would lock the bearing in the race and would NOT allow it to wobble in the race as it is designed to do.

Otherwise, a good synopsis in my view.

 

[Albin]

As usual, the lead-in at about 0.09 by the media got it wrong. Boeing was not the manufacturer, Douglas Aircraft was the manufacturer but inherited the aircraft after acquiring MDC. This was clarified later in the video.

At 16:25 he makes an incorrect comment about a "tongue-and-groove" design.

The race's "groove" is there to act as grease entrainment.

There is no tongue on the spherical bearing. A tongue would lock the bearing in the race and would NOT allow it to wobble in the race as it is designed to do.

Otherwise, a good synopsis in my view.

I took it that he knew he misspoke when he said it; slip of the tongue, no real biggie in the scheme of things.

The bigger point is that Boeing should have known better and called for a) shorter inspection and/or re-greasing interval or b) redesigned the joint altogether - over 14 years ago.

They made a bet - and it backfired horribly.

 

[MolaKule]

I took it that he knew he misspoke when he said it; slip of the tongue, no real biggie in the scheme of things.

I took it that the Media blurb was the lack of proper background reasearch and ignorance of the facts. Media needs to report as factually as possible; this was pure laziness on their part.

Captain Steeve also made some incorrect statements from 10:45 to about 11:15 regarding the design of the spherical bearing assembly.

The bigger point is that Boeing should have known better and called for a) shorter inspection and/or re-greasing interval or b) redesigned the joint altogether - over 14 years ago.

Boeing did redesign the spherical bearing assembly and suggested it with a new part number (See about 11:20 to 11:50), but left it to the airlines to install it. Perhaps using a "stronger" language might have helped, who knows?

Where was the FAA and their supposed oversight in this matter? Why didn't they get involved and force the replacement and reduce inspection periods since they had the Boeing documents?

As a former aerospace scientist who had worked in Stress and Fatigue analysis, I think the spherical bearing race was either not thick enough, or did not have the proper heat treatment, or the groove had the wrong profile.

One item that a stress and fatigue person learns early on, is that any groove or part is not to have a sharp lip or transition but should have a fillet since:

• Stress concentration is a problem of load-bearing mechanical parts which is reduced by employing fillets on points and lines of expected high stress. The fillets distribute the stress over a broader area and effectively make the parts more durable and capable of bearing larger loads. Wiki

Over time, a straight groove without a fillet will experience stress concentrations leading to failure which, in this case, was a splitting of the spherical bearing race.

 

[Just a civilian pilot]

So it’s confirmed the aircraft also lost power on the tail engine which explains why it couldn’t climb out of ground effect.

 

[MolaKule]

So it’s confirmed the aircraft also lost power on the tail engine which explains why it couldn’t climb out of ground effect.

Yes. I think we have to assume those "minor" engine #2 pertubations quickly turned into "major" pertubations.

I would love to see what fodder that engine ingested.

 

[Just a civilian pilot]

Yes. I think we have to assume those "minor" engine #2 pertubations quickly turned into "major" pertubations.

I would love to see what fodder that engine ingested.

Agreed.

Pretty sure I recall hot engine gasses getting sucked into another engine was part of the reason it wasn’t able to climb well ( Concorde crash ).

Curious if that was also why the tail engine lost thrust ( debris and sucking in hot gases from the wing fire ) with the UPS crash.

RIP to the crew, they were doomed.

Who would ever think you could lose an engine at V1 and also lose thrust on the tail engine because debris gets sucked in because of its location behind a wing mounted engine.

 

[mk378]

The flight recorder shows that the throttle on the other 2 engines was increased twice after engine 1 fell off, and engine 2 did respond at first but it died 2 seconds before the crash.

 

[walterjay]

Over time, a straight groove without a fillet will experience stress concentrations leading to failure

This is very interesting. Could you show an example of a filet. I don't know what I am searching for.

 

[Just a civilian pilot]

The flight recorder shows that the throttle on the other 2 engines was increased twice after engine 1 fell off, and engine 2 did respond at first but it died 2 seconds before the crash.

If you aren’t climbing well, firewall by pushing them full forward.

Firewall on engines you can over boost and TOGA ( also full forward but you won’t over boost ) on Fadec controlled engines.

They did everything they could do but they were extremely heavy, on one engine and obstacles at the end of the runway. Even if they were able to climb, the wing would have disintegrated due to the wing fire.

RIP.

 

[goblin]

Sometimes doomed means doomed...

I often think about Vladimir Komarov's story. Launched on a space mission in a half-arsed spacecraft, he got through every possible problem and its brother, and crunched through all of them without batting an eyelid.

At some point he did orbit calculations in his mind as the computer failed as well, in a span of seconds, then manually fired boosters that the computer was supposed to fire with a precision in the order of 0.3 seconds or something like that. Got through all of it, solved it all, alone, never giving up, then went into final descent and could call it a day with nothing to do for the last few minutes.

Turned out his capsule's parachute had fuzed itself into its container/cylinder during manufacturing (unofficial reports go that during assembly they had to use wooden mallets to finish packing the thing in). As it never got out, the drogue parachute remained close to the capsule trying to get it out. The backup parachute got tangled in the drogue, and this whole beautiful circus hit the ground at 80mph.

In a valiant effort to kill any chances of survival, should he had remained alive by any chance (which he very likely wasn't) - the retro-boosters that were supposed to ignite 5ft off the ground, only fired after the crash (as it all went too fast for them), transforming everything into a Niagara of molten metal.

Guy went above and beyond what was humanly possible to get the job done. To no avail.

 

[MolaKule]

This is very interesting. Could you show an example of a filet. I don't know what I am searching for.

Search for, "mechanical fillet" or "fillet in mechanical engineering."

 

[Albin]

What I don't understand is how Boeing could have ever decided that failure of that part "posed no safety of flight issue" (paraphrasing) when they already had solid evidence of taking down airplanes.

I bet whoever made that assessment and approved were drawing MacDac paychecks.

 

[Faawrenchbndr]

What I don't understand is how Boeing could have ever decided that failure of that part "posed no safety of flight issue" (paraphrasing) when they already had solid evidence of taking down airplanes.

I bet whoever made that assessment and approved were drawing MacDac paychecks.

It’s all about risk analysis

If every potential failure point were considered a safety of flight, aircraft simply would not get off the ground.

 

[Vexorg]

This is very interesting. Could you show an example of a filet. I don't know what I am searching for.

Here is a generic example.

 

[Astro14]

Another video on the recently released NTSB report, this time from one of my favorite aircraft/pilot YTers. I'm only 3 minutes in, so have no idea his final conclusions.

I watch his channel - but he is cringy and annoying. Really cringy.. really, really annoying.

His explanations aren’t as clear as I think they should be. He is merely OK, but he is trying to reach out to the non-pilot group in explaining things.

 

[MolaKule]

What I don't understand is how Boeing could have ever decided that failure of that part "posed no safety of flight issue" (paraphrasing) when they already had solid evidence of taking down airplanes.

I bet whoever made that assessment and approved were drawing MacDac paychecks.

We already discussed this in post #269.

 

[barryh]

 

[Just a civilian pilot]

I can’t handle most of the YT aviation channel/podcast “ experts” - except Juan Browne.

They remind me of the media, in a big rush to offer their analysis just to get more clicks than their competition.

Heard an ex fighter pilot on his channel say Airbus are more prone to wrinkled fuselages after either landing on the nose wheel first ( porpoise ) , or bouncing off the mains and then the nose wheel being pushed down impacting the runway.

Saw a video the other day where an Airbus A321 bounced and the nose wheel impacted the runway as a result and I didn’t see the fuselage wrinkled, but I saw a nose wheel tire rolling down the runway.

A guest on his show had to assure him Airbus are not prone to fuselage wrinkles anymore than Boeing are.

What type of plane is more prone to the fuselage getting wrinkles?

ANY type where a pilot rams the nose wheel into the runway.

Hard to believe how easy some make money on the internet today.