Omega Owners Forum
Chat Area => General Discussion Area => Topic started by: Marks DTM Calib on 05 November 2025, 09:37:52
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Interesting one this and some good images and coverage if you are into that sort of thing.
When I visited the US earlier in the year I was surprised then to see MD11s still in use for cargo, and sadly one has gone down.
Some interesting shots of the wing on fire and an engine sat at the side of the runway!
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Interesting one this and some good images and coverage if you are into that sort of thing.
When I visited the US earlier in the year I was surprised then to see MD11s still in use for cargo, and sadly one has gone down.
Some interesting shots of the wing on fire and an engine sat at the side of the runway!
Lots of old jets get used for cargo. There are hardly any Boeing 747's left in passenger service, but lots have been converted to cargo and still trog around the skies. MD-11's are quite popluar because they have very long range and lots of cargo space. Not into civvy, but there were still DC-8's and Electras being used not that long ago.
Cargo jets tend to operate into different airports than passeneger ones, so the public don't tend to notice these older jets. East Midlands Airport is one such cargo hub in the UK.
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East Midlands Airport is one such cargo hub in the UK.
I believe Mr DTM's favourite airport, and not just because it's on his doorstep :y
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The MD11 is a turd of an aircraft, just like the DC10 it's based on. It is a decent size aircraft and can carry a fair amount of weight, so makes a good freighter. Doesn't have a particularly good safety record though.
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Horrendous crash. Clearly a serious uncontained engine failure or something similar. I feel for the crew and anyone in its path on the ground. Once that hit V1 their fate was sealed and they just got to watch it unfold before them. :(
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The only saving grace is that they didn't suffer it for long ;(
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The only saving grace is that they didn't suffer it for long ;(
.. and that it was full of Amazon packages not passengers and more crew.
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The only saving grace is that they didn't suffer it for long ;(
.. and that it was full of Amazon packages not passengers and more crew.
True enough :y
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https://youtu.be/mHW6HaS5mnc?si=J9lPvMZ_FTofaAd2
They've not mentioned a bird strike, but...
https://youtu.be/UvftcahcYsY?si=2sfMhxgDdmuH7X4k
Not the ATC recording of the actual incident but it does include the ATIS information for Louisville at the time which includes mention of increased bird activity.
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Its interesting that it ejected the main section (less the fan) of the port engine, claims that you can then see the tail engine flame out.
So you are now in a world of an engine cavity on fire and down to less than a third of the thrust.
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It would take quite a bird strike to rip an engine off its pylon and dump it by the runway, but it's not impossible that one started the whole chain of events, I suppose. :(
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I assume that cargo aircraft are subject to the same fairly stringent maintenance and safety checks of passenger jets? If so, and that it was actually done, would that point more towards the mass bird strike DG hinted at? Perhaps with a catastrophic failure of the first engine causing it to become detached from the wing, and then enough damage to stop the rear engine?
Or debris from the first failure (caused by birds or an unfortunate mechanical failure) causing damage to the rear engine?
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One problem with the Trijet configuration is that No. 2's intake is prone to ingesting disturbed air / debris if anything happens to 1 & 3, especially after rotation when the wing is working hard.
With that amount of fire, engine thrust might have been moot, however. I wonder if there would have been enough left of the wing structure for it to remain controllable for a go-around even if it had climbed away.
Thoughts of the AF Concorde crash come to mind.
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When your times up that's it ,doesn't make any difference where you are or what mode of transport you're on it's as simple as that.
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Latest dashcam footage shows the port engine completely detached, which suggests more than a bird strike.
This has happened before on a DC10
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Only way a birdstrike makes sense is if the engine swallowed a big bird (or birds) and suffered enough damage for the resulting vibrations to shake the engine off the wing. Not impossible, but not very likely either.
The engine pylon fixings are frangible - they are supposed to break if there is enough engine vibration to endanger the structural integtiry of the wing/airframe. AIUI the MD-11 has two main engine fixings on each pylon under the wing. There was a previous crash where the rear fixing broke, but that caused the engine to pivot forwards and upwards, and it departed over the top of the wing. That doesn't appear to have happened here. My money is on the front fixing breaking, which I think would result in a forwards and downwards departure if it happened at or after rotate when the wing is pulling upwards.
If that's correct, then we're looking at either poor maintainace, or counterfeit parts. It's also possible there was a fire in the wing first, which then damaged the fixings. Either way, nothing the crew could do, and once the second tail engine starts to lose thrust the outcome is sealed. No way a heavy MD-11 is going anywhere but down on one engine.
RIP the crew, and those caught on the ground.
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This has happened before on a DC10
Do you mean This one? (https://en.wikipedia.org/wiki/American_Airlines_Flight_191)
If so you'd hope that the lesson of not fuŁking about with the manufacturer's maintenance procedures had been well learned! ::)
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It would take quite a bird strike to rip an engine off its pylon and dump it by the runway, but it's not impossible that one started the whole chain of events, I suppose. :(
By the time it's bounced over the airfield, the external gubbins would have been smashed to bits, the core is the heaviest part so no surprise that it's on its own.
The pylons have always been a week link on those. DC10/MD11s. The AD that came from the Chicago crash in the late seventies focused on maintenance practices rather than the aircraft. The engines themselves aren't actually held on by much.
Whilst the casing should be able to contain a fan blade failure, regardless if cause, the rotational force at take off power could have been enough to twist the pylon off.
Engine #2 probably ingested the fragments of #1 as it disintegrated., something more likely due to the relative tail position as the nose came up. By contrast, the engine in the Chicago incident simply became detached and missed the tail. In this case the engine coming away was a secondary event. As was the engine fire. Once the engine came away, the subsequent roll to the left was guaranteed.
#2 failing was actually a blessing as the aircraft never gained altitude.
FOD or mechanical failure.
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This has happened before on a DC10
Do you mean This one? (https://en.wikipedia.org/wiki/American_Airlines_Flight_191)
If so you'd hope that the lesson of not fuŁking about with the manufacturer's maintenance procedures had been well learned! ::)
The only similarities are aerodynamic consequence. Erase that engine and it's thrust and the resultant roll is swift and catastrophic and will happen every single time.
Incidentally, not many operators own any and fleet utilisation is pretty low...
https://en.wikipedia.org/wiki/List_of_McDonnell_Douglas_MD-11_operators
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This has happened before on a DC10
Do you mean This one? (https://en.wikipedia.org/wiki/American_Airlines_Flight_191)
If so you'd hope that the lesson of not fuŁking about with the manufacturer's maintenance procedures had been well learned! ::)
The only similarities are aerodynamic consequence. Erase that engine and it's thrust and the resultant roll is swift and catastrophic and will happen every single time.
Incidentally, not many operators own any and fleet utilisation is pretty low...
https://en.wikipedia.org/wiki/List_of_McDonnell_Douglas_MD-11_operators
The main issue with AA191's loss of control was retraction of the slats on the port wing and the consequent asymmetric stall due to hydraulic damage, an issue that was countered by an AD in response to the crash investigation.
There's no roll I can see on the videos of this crash, at least not until the port wing contacts something solid on the ground and the airframe cartwheels.
Aerodynamically, it's an engine failure, so possible to counter with control inputs assuming you still have a working system by which to make them.
Add a load of fire and a second engine failure and there is, of course, no hope.
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AA191 had alot more altitude so was almost inverted when it hit.
The two things they needed they didn't have... Airspeed and altitude. The wings will always provide lift as long as there is air flowing over it. Removing thrust on one side causes a loss of airspeed over that wing. Less airspeed equals less lift. Likewise the yaw induced by the loss of balanced thrust further slows the unpowered wing causing more loss of lift. As the wing drops the aircraft will always roll to that side. Once the left wing touched the lift from the working wing finished the roll.
Not dissimilar to the Endeavour crash in Toronto earlier this year.
The position of the tail engine relative to the dynamic axis is less than ideal compared to the Tristar or other three engined aircraft. Where the centre line of the engine is almost aligned with the centre line of the aircraft.
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The two things they needed they didn't have... Airspeed and altitude. The wings will always provide lift as long as there is air flowing over it. Removing thrust on one side causes a loss of airspeed over that wing. Less airspeed equals less lift. Likewise the yaw induced by the loss of balanced thrust further slows the unpowered wing causing more loss of lift. As the wing drops the aircraft will always roll to that side. Once the left wing touched the lift from the working wing finished the roll.
Yes, but all of these effects of asymmetric thrust are possible to counter with control inputs until the wing stalls, which didn't happen in this incident, judging by the footage I've seen, but did, almost instantly, for AA191 due to slat retraction below the clean stalling speed. I'd say the crew in this case did a great job of keeping the aircraft flying to the crash site. Sadly, it didn't help them or the souls on the ground.
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It is not true that "wings will always provide lift as long as there is air flowing over it". Once a wing stalls, all it provides is drag.
AA191 crashed in the way it did because the crew reduced speed to V2 when they realised something was wrong. That's what the checklist says to do on a DC10 in the event of engine failure during take-off/climb out. However, the crew did not realise they had also lost hydraulic pressure in the left wing, and that loss caused the leading edge slats to retract. With no leading edge slats, V2 is not fast enough for a wing to produce lift and the left wing stalled. The right wing did still have flaps an slats, so was still producing lift. The result of lift on the right wing and a stall on the left wing are what caused AA191 to roll left and crash in the way it did. If the crew had maintained their original speed, the left wing would not have stalled, it would not have rolled left, and simulator test showed the plane could have remained airborne - although given it was on fire and had compromised hydraulics no way of knowing how long it could have remained airborne.
In this case, the plane appears to have been level until it hit the ground. Dashcams show no evidence of roll.
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I may have worded that better: in a normal attitude with sufficient air moving at a high enough speed would have been clearer.
All slats and spoilers do is change the shape of the wing as required to maximise lift/reduce drag at any given airspeed. Note that drag is not the opposite of lift.
It's a pretty moot point though... 150ft isn't enough altitude to do anything with.
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All slats and spoilers do is change the shape of the wing as required to maximise lift/reduce drag at any given airspeed. Note that drag is not the opposite of lift.
You say that as if they are insignificant. The significant thing they do is to reduce the stall speed of the wing so that the aircraft can operate at the lower airspeeds used during approach and the initial climb.That can come at a significant cost in terms of drag too with some configurations, but that is actually an advantage on approach, because you need to be able to shed energy and the engines are kept at a higher thrust setting and can respond faster if a go-around is initiated.
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Not at all insignificant, but it's a wonder the thing actually got off the ground with less than two engines.
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The MD11 is a turd of an aircraft, just like the DC10 it's based on. It is a decent size aircraft and can carry a fair amount of weight, so makes a good freighter. Doesn't have a particularly good safety record though.
I think that is an understatement :o :o
I remember the one crash in Northern France, that we amazingly heard the sound of on the beach in Hastings!! A cargo door came off with that one, and I have just looked up the crash record of the DC10, which confirms that door was the cause of many crashed ........55 in total!! :o :o
To quote Goggle - "The DC-10 has been involved in 55 accidents and incidents, including 32 hull-loss accidents, with 1,261 fatalities. Some sources provide slightly different numbers, such as 29 crashes and over 1,000 deaths, but the overall statistics indicate a high number of accidents for this aircraft"
Wow!! I knew the record was bad, but that is staggering. I just remember having to fly on a Lockheed 10/11 Tristar in 1998 across the USA, and although a completely different aircraft and manufacturer than the DC10, was nervous about doing so for some reason! My mind could not help remembering the record of the latter! ::) ::) ::)
I have just also researched the Northern France crash of 1974, and once more Google states:
"The DC-10 crash in northern France refers to Turkish Airlines Flight 981, which crashed on March 3, 1974, in the Ermenonville Forest, about 40 kilometers (25 miles) northeast of Paris. All 346 people on board were killed, making it the deadliest single-aircraft accident without survivors in aviation history.
The cause of the crash was the in-flight ejection of the rear cargo door due to a design flaw that allowed the door to appear fully locked when it was not. The resulting explosive decompression caused the cabin floor to collapse and severed the control cables necessary to fly the aircraft, leading to a complete loss of control"
That day I remember so well due to that sound and the news we picked up later on the car radio! :o :o
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They're currently all grounded pending the investigation findings.
Much of the UPS and Fed Ex fleets are already in storage, so slightly moot.
The TriStar was a much better aircraft than the DC10/MD11. Its undoing was because it crashed first.
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There seems to be talk that Engine 3 filmed out just after nose came up. Could debris from Number 1 have penetrated the fuselage, and cargo in that area, and out again to damage No 3?
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There seems to be talk that Engine 3 filmed out just after nose came up. Could debris from Number 1 have penetrated the fuselage, and cargo in that area, and out again to damage No 3?
#3 is the tail engine. Anything departing #1 with enough energy to penetrate the fuselage is going to miss the tail engine.
However, if the whole #1 detaches from the wing then it doesn't just fall to the ground like a dumb bomb. At the moment of departure it's sucking in huge mounts of air, and thrusting out tens of thousands of pounds of thrust. On detaching it actually accelerates forwards of the plane for while before drag slows it down, and then the plane catches it up and 'crashes' into it. Also, any sections of the wing that are damaged during the detachment, (or by things like fan blades puncturing the wing), can/do get sucked upwards and over the wing. The fan blades themselves will probably miss the tail engine, but secondary damage canget sucked into the tail engine.
I don't think there has ever been an incident of an engine failure on one wing causing damage to an engine on the other wing. If that could happen, then the safety case for virtually all twin engined aircraft goes to pot.
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Sorry - that first sentence should have been....
"#3 is the tail engine? Anything departing #1 with enough energy to penetrate the fuselage is going to miss the tail engine."
Point is, I can't find any instances of an engine on one wing causing damage to an engine on t'other wing. Yes there have been instances (on both B-707's and B-747's) where one engine has failed and knocked the other one on the same wing off, but never on the opposite wing.
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No.3 would be the engine on the starboard wing. They are counted from port to starboard.
I think the cowling of the departed no.1 engine ended up the other side of the runway so quite possible it killed no.3.
However, one of the videos shows no. 2 at the back spitting out sparks just after rotation. It quite possibly ingested fire from the burning port wing at that point.
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Yes, to clarify, it is the starboard engine I'm talking about the rumours of it flaming out as the nose lifts. Which as Kevin Wood says, is called No3.
Additionally, there is also talk of there being a direct line of sight between the No1 and No3, under the fuselage, so maybe it didn't penetrate the fuselage.
As a cargo plane, my thoughts were how likely would it be for engine debris, admittedly at high speed with a lot of spin, to penetrate the fuselage (easy, thin aluminium) and the cargo (less likely?)
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As a cargo plane, my thoughts were how likely would it be for engine debris, admittedly at high speed with a lot of spin, to penetrate the fuselage (easy, thin aluminium) and the cargo (less likely?)
There is no real difference between a cargo and a passenger planes construction. Some cargo planes do have a strengthened floor to take the weight of pallets and extra loading doors, but the wings, skins and bulkheads are the same. I don't think the cargo has any bearing on this, because for parts of an engine to hit the cargo they have to travel up, so they will miss the other engine if they emerge out the other side of the fuselage.
AIUI there are contained and uncontained engine failures. Smaller things like individual engine blades are supposed to be contained within the engine cowling if they break off. The engine will be destroyed, but things shouldn't fly out of the sides. This is tested during engine certification, and is often implemented by having kevlar bands around the engine. Larger parts - like rotor disks (either whole or segments) are considered to have infinite energy and cannot be contained. If they do break off, they will go through virtually anything. The safety mitigation for these is simply to route critical wiring and hydraulics out of being in direct line with the high energy rotating parts. Engines are also mounted forwards of the front wing spar, so if anything does fly off it doesn't puncture fuel tanks.
If some high energy part of #1 did escape and somehow hit #3 it will be the first known incident of this happening. It will have very serious consequences for air travel. Aircraft are certified to be able to takeoff, fly and land on n-1 engines on the basis that it's highly unlikely that two engines can be damaged by the same event. If that assumption proves to be false then it opens a huge can of worms. n-2 isn't possible on any aircraft, and since almost all are now twins (B-737,767,777,787,A-319,320,330,350) n-1 means zero.
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As a cargo plane, my thoughts were how likely would it be for engine debris, admittedly at high speed with a lot of spin, to penetrate the fuselage (easy, thin aluminium) and the cargo (less likely?)
There is no real difference between a cargo and a passenger planes construction.
Yes, the bit I was wondering is if debris would penetrate the cargo easier than it would penetrate the organic matter in a passenger jet....
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As a cargo plane, my thoughts were how likely would it be for engine debris, admittedly at high speed with a lot of spin, to penetrate the fuselage (easy, thin aluminium) and the cargo (less likely?)
There is no real difference between a cargo and a passenger planes construction.
Yes, the bit I was wondering is if debris would penetrate the cargo easier than it would penetrate the organic matter in a passenger jet....
Pax planes are usually full of seats, which are partly made of metal. I've got a memory of one incident where engine bits were discovered embedded in the seats, but can't remember which accident that was. It's simply pot luck if an engine fragment hits something soft and squishy or hard and resilient. Heavy/dense cargo is likely to be placed close to the centre of lift/gravity, so over the wings and behind the line of the engines. However, no way of knowing if this plane was carrying a load of light teddybears or the lead lining for a nuclear reactor.
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Rotation puts the tail engine at or below the Centre of Gravity, ie about level with the front wing spar and therefore in the firing line of any debris.
Pretty sure the tail engine is actually #2.
No mention yet that I have seen of a bird strike but there was report of increased bird activity before the crash.
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NTSB preliminary report is out. :o
https://www.ntsb.gov/investigations/Pages/DCA26MA024.aspx (https://www.ntsb.gov/investigations/Pages/DCA26MA024.aspx)
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NTSB preliminary report is out. :o
https://www.ntsb.gov/investigations/Pages/DCA26MA024.aspx (https://www.ntsb.gov/investigations/Pages/DCA26MA024.aspx)
Wow. That series of still images is quite chilling.
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NTSB preliminary report is out. :o
https://www.ntsb.gov/investigations/Pages/DCA26MA024.aspx (https://www.ntsb.gov/investigations/Pages/DCA26MA024.aspx)
Non of the media content on that page is viewable* :-\
https://youtu.be/UpUkwzVUs5Y?si=WGyxm3jv-EjiOqu9
This should cover it...
Incidentally, given the proximity to the ground pictures 5 and 6 show a pronounced (for that point in the take off) roll to the left... It was a coin toss as to whether the left wing tip lower scimitar fin hit the ground or not... If it had, the aircraft wouldn't have left the airfield.
* Not in the UK so it could simply be that.
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This was in January this year, but adds weight to the possible trigger event...
https://youtu.be/npY42pcf1VI?si=BsvkXjaagx3oN-De
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Page 9 of the initial report states...
After initial cleaning of the fracture surfaces, examination of the left pylon aft mount lug
fractures found evidence of fatigue cracks in addition to areas of overstress failure. On the aft
lug, on both the inboard and outboard fracture surfaces, a fatigue crack was observed where
the aft lug bore met the aft lug forward face. For the forward lug’s inboard fracture surface,
fatigue cracks were observed along the lug bore. For the forward lug’s outboard fracture
surface, the fracture consisted entirely of overstress with no indications of fatigue cracking.
The forward top flange of the aft mount assembly was examined for indications of
deformation or pre-existing fractures, but no indications were found. The spherical bearing
was removed from the wing clevis for further evaluation (see figure 10).
What they're saying is there were pre-accident fatigue cracks in 3 of the 4 mounting lug surfaces for the #1 engine. The engine "fell off" when the 4th lug gave way under the overstress of the take off. Whilst it's possible a bird strike was the straw that broke the camels back, the root cause of the accident is the fatigue cracks. It appears the design can withstand cracks in one and two of the 4 lugs, but if/when the third cracks the fourth isn't strong enough to hold it all together. And you wouldn't expect it to be.
So the report will IMHO concentrate on how/why these cracks occur, and how to inspect them such that the fault is detected when the first crack appears, rather than waiting for the engine to fall off when all 4 become cracked.
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What they're saying is there were pre-accident fatigue cracks in 3 of the 4 mounting lug surfaces for the #1 engine. The engine "fell off" when the 4th lug gave way under the overstress of the take off. Whilst it's possible a bird strike was the straw that broke the camels back, the root cause of the accident is the fatigue cracks. It appears the design can withstand cracks in one and two of the 4 lugs, but if/when the third cracks the fourth isn't strong enough to hold it all together. And you wouldn't expect it to be.
So the report will IMHO concentrate on how/why these cracks occur, and how to inspect them such that the fault is detected when the first crack appears, rather than waiting for the engine to fall off when all 4 become cracked.
Indeed. Bird strike or not, that aircraft was an accident about to happen when it started its take-off roll, and potentially so is the rest of the remaining MD-11 / DC10 fleet. Given its obsolete status and the fact that there are relatively few airframes left flying, I wouldn't be surprised if the inevitable inspection and rectification actions that would be required to continue safe flight turn out to be prohibitively expensive.
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Thing is with the DC10/MD11 it's large enough to be useful but not so large as to be too expensive to operate. If UPS and FedEx suddenly have to scrap them, then there's not much to replace them with. The A330 doesn't age well and all the bigger Boeings are either already converted or have been scrapped :-\
It's a surprise that this failure hasn't happened more often and it will be interesting to see how many aircraft are about to fail. It also begs the question as to how such a high cycle airframe had yet to reach the inspection threshold. Replacing the parts and dropping the inspection to 2,500 hours might be enough.
The only operators that might not be able to afford it are the flying hospital and the fire tankers which is a bit ironic as they're probably better maintained due to their more specialist uses.
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There are 60 odd ex USAF KC-10's stored in the boneyard at Davis Monthan/Tuscon. They were only retired about a year ago. They've only ever been operated by the USAF, and were in service from 1979 ish. The last ones were built (tecnically funds were allocated) in 1987. The hours and cycles on these airframes will be well documented.
If I were NTSB I'd be asking the USAF if they wouldn't mind stripping the engines and pylons off a handful of them so they can inspect the parts that broke assuming the KC10 uses the same or similar parts.
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There are 60 odd ex USAF KC-10's stored in the boneyard at Davis Monthan/Tuscon. They were only retired about a year ago. They've only ever been operated by the USAF, and were in service from 1979 ish. The last ones were built (tecnically funds were allocated) in 1987. The hours and cycles on these airframes will be well documented.
If I were NTSB I'd be asking the USAF if they wouldn't mind stripping the engines and pylons off a handful of them so they can inspect the parts that broke assuming the KC10 uses the same or similar parts.
Can't see them being any different tbh, the aircraft are fundamentally the same. The designers should have forseen the potential issue as the engines are mounted a fair distance forward of the main spar. To the point it's unusual.
Be interesting to see if the 737 Max will develop similar failures over time from mounting the engines forward and up from the original -300/800 design :-\