SDF UPS down

Kenny Phillips said:
Well, part of the engine is on the runway. The fan appears to be AWOL, the fan shroud material perhaps shredded and ingested. A fan letting go can create an imbalance that could take an engine off, which means that what happened to the mounts proper (at either end of the pylon) is moot.
Click to expand...
From yesterday's Juan Brown video, he steps through some of the still photographs that (IIRC) show parts of engine #1 on the left side of the runway in roughly the following order: (a) part of the engine nacelle, then (b) a little further beyond, part (all?) of the pylon, then (c) a little beyond that, the engine itself. I don't know if the location of the debris gives a accurate indication as to the order in which things transpired with engine #1, but I do agree that these items will be available for inspection/investigation and I'm sure will yield valuable info.
 
luvflyin said:
I’m wondering how did it depart the wing. Did it drop and roll? Or did it get launched over the wing? Where is the pylon?
Click to expand...
Very likely to have gone up and over as the engine is still producing thrust and suddenly has no airplane to pull. There is a lot of inertia in the spool which will continue to produce thrust as it slows down.

3393RP said:
I think the likelihood of finding the cause of the separation will be difficult.
Click to expand...
They are very good at this. They can analyze the failure point(s) and determine the cause of the failure. On UA232, they were able to analyze the failed fan hub of the No.2 engine and determine that it was machined from a flawed block of titanium alloy and that failure occurred at cruise altitude.

kmacht said:
The engine is sitting there on the runway. Go look at the engine mounts on that engine
Click to expand...
Very likely that the failure occurred in the pylon, not the engine as that is the weakest point. A failure in the engine may have caused the failure in the pylon. The engines are designed to separate at the pylon to try to minimize the damage to the wing during a catastrophic failure.
 
Larry in TN said:
Very likely to have gone up and over as the engine is still producing thrust and suddenly has no airplane to pull. There is a lot of inertia in the spool which will continue to produce thrust as it slows down.


They are very good at this. They can analyze the failure point(s) and determine the cause of the failure. On UA232, they were able to analyze the failed fan hub of the No.2 engine and determine that it was machined from a flawed block of titanium alloy and that failure occurred at cruise altitude.


Very likely that the failure occurred in the pylon, not the engine as that is the weakest point. A failure in the engine may have caused the failure in the pylon. The engines are designed to separate at the pylon to try to minimize the damage to the wing during a catastrophic failure.
Click to expand...
Did the designing to separate at the pylon happen after AAL191?
 
Larry in TN said:
Very likely to have gone up and over as the engine is still producing thrust and suddenly has no airplane to pull. There is a lot of inertia in the spool which will continue to produce thrust as it slows down.
Click to expand...
That would make the engine want to go forward, but not necessarily "up and over". The reason AA191's engine went up and over was that the rear pylon fitting failed first, so the engine rotated around the front fitting and pointed up before it fully separated.

Larry in TN said:
They are very good at this. They can analyze the failure point(s) and determine the cause of the failure. On UA232, they were able to analyze the failed fan hub of the No.2 engine and determine that it was machined from a flawed block of titanium alloy and that failure occurred at cruise altitude.
Click to expand...
Yes. The NTSB does some amazing work to get down to the cause of a crash, and in this case they at least have the engine that separated as well as good data from both FDR and CVR.
 
Cant remember which of the 3 bolts failed but on the 747 crash in amsterdam (Bijlmer crash and i thought it was elal cargo) but there the number 3 engine flew forward initially, then sideways and took out the number 4.
 
luvflyin said:
Did the designing to separate at the pylon happen after AAL191?
Click to expand...

This is the crash I've had in mind as the fault with AA 191 was caused by damaged to the engine pylon mounts because the mechanics deviated from manufacturer-recommended installation protocols. I wonder if that's the case here ...
 
Daleandee said:
This is the crash I've had in mind as the fault with AA 191 was caused by damaged to the engine pylon mounts because the mechanics deviated from manufacturer-recommended installation protocols. I wonder if that's the case here ...
Click to expand...
If so, you can bet the shredders have been running at the MRO facility.
 
Hard to imagine the rest of these fleets are still flying right now.
 
Hengelo said:
Hard to imagine the rest of these fleets are still flying right now.
Click to expand...
My guess since they have the big pieces, they have a basic idea of the failure sequence which does not require the FAA or UPS to stand down the fleet after the initial 24 hrs. Keep in mind, the fan and duct cowling (with evidence of blade strikes) had also separated from the core engine during the failure sequence and was also left on airport property.
 
Hengelo said:
Hard to imagine the rest of these fleets are still flying right now.
Click to expand...
Why? MD-11s entered commercial service in December of 1990. Almost 35 years of service without this failure happening before.

We don't ground airplanes until we have identified a specific issue which invalidates the airplane's airworthiness certification.

Since they have the pylon, they can do the metallurgical analysis which will identify the reason for the failure. If they find pre-existing fatigue or stress cracks, expedited inspections or a grounding my be justified. If they found it failed under loads which exceeded the design limits then there is not a reason for a grounding.

Bill said:
So more like 191 than we thought :-(
Click to expand...
Not really. As I said, the pylons are designed to be the separation point so as to minimize damage to the wing after such catastrophic failures. If that's where it failed, that would be as expected.

There is video evidence suggesting a major uncontained fan failure which could turn out to be the proximate cause that resulted in the fire and the engine separation. All we have is the video of the fire and that the fan section was separated at this point. Not enough to draw such conclusions.

There have been other cases of engines separating from transport aircraft including AA191 (DC10), El Al 1862 (747), China Airlines 358 (747), DAL1288 (MD88), China Airlines 301 (727), NWA 5 (727), National Airlines (727), AAL (727), and probably more.
 
@Larry in TN , yeah further inquiring says maybe a turbine failure in the aft portion of the engine. Any which way, these poor guys were dealt a really bad hand. Tail winds.
 
Larry in TN said:
The NTSB, this afternoon, said that most of the pylon was still connected to the engine.
Click to expand...
That's good. I did say the determination of cause will be difficult, but fortunately not impossible. The forensic examiners of the NTSB are thorough.
 
Hengelo said:
Hard to imagine the rest of these fleets are still flying right now.
Click to expand...
Yeah - To some extent I feel like the trijet design with wing-mounted engines needs to be done due to the possibility of one engine failure taking out a second one in this manner. I can't think of any type other than the MD-11 that's still flying in this configuration, though.

kyleb said:
Millions of flight hours testify that the design is solid.
Click to expand...
Meh... 11 complete hull-loss accidents out of 200 airplanes built does not inspire confidence. In fact, that's one of the worst accident records of a semi-modern airliner.
 
flyingcheesehead said:
Meh... 11 complete hull-loss accidents out of 200 airplanes built does not inspire confidence. In fact, that's one of the worst accident records of a semi-modern airliner.
Click to expand...
IIRC, this is a relatively difficult aircraft to land. High speed, sight picture issues, etc. causing several accidents. The accidents have not been of the "ripped an engine off on takeoff" variety, which is what we're looking at here...
 
MFE said:
Fleets are being grounded as I type this
Click to expand...
Yep. Looks like ~108 on the US registry; 30 are UPS based in Kentucky, 61 are FedEx based in Tennessee.
So most of them are grounded with just the two carriers pulling them.
 
Larry in TN said:
Why? MD-11s entered commercial service in December of 1990. Almost 35 years of service without this failure happening before.

We don't ground airplanes until we have identified a specific issue which invalidates the airplane's airworthiness certification.

Since they have the pylon, they can do the metallurgical analysis which will identify the reason for the failure. If they find pre-existing fatigue or stress cracks, expedited inspections or a grounding my be justified. If they found it failed under loads which exceeded the design limits then there is not a reason for a grounding.


Not really. As I said, the pylons are designed to be the separation point so as to minimize damage to the wing after such catastrophic failures. If that's where it failed, that would be as expected.

There is video evidence suggesting a major uncontained fan failure which could turn out to be the proximate cause that resulted in the fire and the engine separation. All we have is the video of the fire and that the fan section was separated at this point. Not enough to draw such conclusions.

There have been other cases of engines separating from transport aircraft including AA191 (DC10), El Al 1862 (747), China Airlines 358 (747), DAL1288 (MD88), China Airlines 301 (727), NWA 5 (727), National Airlines (727), AAL (727), and probably more.
Click to expand...
Lotsa 727’s. What about the engines. This one had a GE, right? It’s looking like the engine itself may be the culprit here. How many of this particular GE are out there?
 
Bell206 said:
I believe the CF6 is still in production today with variants used on other model aircraft.
Click to expand...
This is definitely a "legacy" engine, with roots back to the early sixties. Things are constantly updated as experience dictated (all test and cert documents were published by my group until I retired last year). The GEnx is the replacement (but not retrofit).
A number of planes use the engine (such as the VC-25A).
 
Kenny Phillips said:
Yep. Looks like ~108 on the US registry; 30 are UPS based in Kentucky, 61 are FedEx based in Tennessee.
So most of them are grounded with just the two carriers pulling them.
Click to expand...

FedEx is operating 27 MD-11's and UPS operates 26 of them.
 
Last edited:
flyingcheesehead said:
Meh... 11 complete hull-loss accidents out of 200 airplanes built does not inspire confidence. In fact, that's one of the worst accident records of a semi-modern airliner.
Click to expand...
Most were landing accidents/hard landings. One was an inflight fire sue to faulty wiring for the inflight entertainment system. One was a Chinese MD11 where a pilot accidentally deployed the slats at altitude.

luvflyin said:
How soon do you think the FAA will ground them all? Aren’t you an MD11 flyer?
Click to expand...
When they find evidence of a problem that could affect the rest of the fleet.

Doc Holliday said:
FedEx is operating 27 MD-11's and UPS operates 26 of them.
Click to expand...
Are the MD10s still flying?
 
"There are about 70 MD-11s in service operated by FedEx, UPS and Western Global, according to Boeing."
 
(Google gave me a number closer to 100)
Reasonable to trust Boeing would know.
 
Very prudent thing for brown to do. A safety down until they parse through the mx questions is a good thing for everybody involved. There's more to life than money and neurotic next-day shipping entitlement.

Good optics for Purple to get in on the safety bandwagon. The fleet in question was earmarked for divestment on both carriers anyways; neither cripples their respective operation, given the economic slowdown the govt is intent on papering over by inflating the USD away at W2 earners expense. Digressing. Both are playing good chess here.
 
hindsight2020 said:
Very prudent thing for brown to do. A safety down until they parse through the mx questions is a good thing for everybody involved. There's more to life than money and neurotic next-day shipping entitlement.

Good optics for Purple to get in on the safety bandwagon. The fleet in question was earmarked for divestment on both carriers anyways; neither cripples their respective operation, given the economic slowdown the govt is intent on papering over by inflating the USD away at W2 earners expense. Digressing. Both are playing good chess here.
Click to expand...
1762625972978.jpeg
 
  • Haha
Reactions: MFE
I'm hoping that the 37 second timing of the bell, which was most likely a fire warning, was due to damage not allowing the signal to process until that time. Otherwise there probably would have been at least a light in the fire handle prior to V1 and maybe some EICAS indication. Which probably would not have been noticed by whoever was in the JS, most likely the relief Captain. Which would be explained by human factors. A relief Captain in the JS might not be in Flight Engineer mode. He might revert to his PF mode and be on the primary instruments and out the window. I hope this was not the case.
 
This is my guess of this events cause. It is based on my experience with GE turbines from the era when this MD 11 was built.


Fail safe, until it is not.

35 years ago, I was the company's leading technician for the 16 turbine bank of emergency generators.

The turbines were a variation of the ones on the first generation Boeing 747s.

The fuel control system went to no flow if the fuses were pulled while the unit was running, the safe thing to do, as the coordinating safety systems were fed from the same fuses.

The actual power setting device had a rheostat that had end reference voltages set at idle power, and max fuel flow. Another good limiting feature.

Unfortunately, if the low power reference voltage had a broken wire or equivalent, the signal went to wide open fuel valve, no limiting device.



A test to see what would happen with the low reference failed, generator at 30% power, and the power output reached 90% in 2 seconds! The mechanic observing outdoors reported a fireball from the exhaust stack, along with a short loud change in the sound of the turbine. The generator side of the protective system would have tripped the fuel lockout before damage occurred

Aircraft do not have this secondary system.

If the GE turbines on this MD 11 had a similar fail safe system and lost the low power reference signal, the thrust lever for No.1 would have become useless, excess fuel would have poured into the engine, and exhaust flames would have developed.

As the plane accelerated down the runway, as soon as one of the pilots noticed the rising RPM of no. 1 engine, they would have pulled back that thrust lever some, them more, and eventually to zero, with no reduction of the rising RPM.

At that point, the only way to save the engine and plane would have been to unlock the fuel cutoff for that engine, and cut off all fuel flow. After Air India, who is going to do that?

Next is the go/no go for the takeoff. With an engine exceeding full takeoff power, can you abort at MTOW? Are you willing to run off the end at speed, and 38,000 gallons of fuel? The choice they seemed to make was get it up, solve the problem, and come back, in some form.

The engine did its own thing, first shedding a few blades and tearing away the cowling, followed by many blades, locking the rotor to the stator of the engine, suddenly twisting the engine counter clockwise, and breaking the safety bolt/pins, and separating from the wing. The engine falls to the runway, breaks off some of the pylon, and rolls to the grass.

A different power company had such a runaway fuel event, hundred foot pillar of flames, locked rotor, and rolled off the concrete pad. Nothing is completely fail safe. One broken wire is all it can take, if the current logic is similar.

That was a tough place to be if that was in fact the events the pilots endured.



For the record, there were 2 men and 1 woman on that aircrew, she was one of the full Captains. Sympathy for all their families, and coworkers.

The turbine drivers here are encouraged to find where technology has progressed to where the above is no longer possible.
 
Last edited:
You must log in or register to reply here.
Back
Top