UPS plane crash

Having watched documentaries about how these parcel services work with the distribution hubs, planes, vans and the sheer logistical nightmare that can occur when it breaks down, I wonder just how much of a plan is in place to recover from losing a huge chunk of their air freight capacity overnight, especially at this time of year.
 
Penfold101 said:
Having watched documentaries about how these parcel services work with the distribution hubs, planes, vans and the sheer logistical nightmare that can occur when it breaks down, I wonder just how much of a plan is in place to recover from losing a huge chunk of their air freight capacity overnight, especially at this time of year.
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Probably not as much as you'd think, 50 aircraft across UPS/Fed-Ex is quite a small number, I think UPS alone routinely uses something like 400+ so potentially less than a 5% drop in capacity in terms of airframes.
They also can and will hire in capacity from other aircraft operators so it'll probably be fun times for the planning staff but I suspect not something they have not got experience and plans in place for, as having a model of aircraft grounded for a while is not unknown and one of the reasons a lot of aircraft operators will try and maintain a mix of different models as they know one incident can result in an entire fleet being grounded for checks.
 
ubersonic said:
Now the FAA have grounded the MD-11 that may well be the planes done now regardless of what the investigation concludes.

As it's an FAA directive FedEx and UPS will now be able to claim off their insurance for the downtime which means from a purely financial POV as they were planning on scrapping the planes imminently anyway it makes sense to not even waste money doing the inspections (and any required remediations/modifications the FAA dictates) required to put them back into service and just accelerate the replacement program.
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I would be surprised if they just scrap them, they have contacts to fulfill and carrying out an AD in the grand scheme of things aviation is not that expensive. They can't just get replacement aircraft off the shelf tomorrow.
 
Werewolf said:
Probably not as much as you'd think, 50 aircraft across UPS/Fed-Ex is quite a small number, I think UPS alone routinely uses something like 400+ so potentially less than a 5% drop in capacity in terms of airframes.
They also can and will hire in capacity from other aircraft operators so it'll probably be fun times for the planning staff but I suspect not something they have not got experience and plans in place for, as having a model of aircraft grounded for a while is not unknown and one of the reasons a lot of aircraft operators will try and maintain a mix of different models as they know one incident can result in an entire fleet being grounded for checks.
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I just checked the numbers on Wikipedia - 27 MD11’s out of a total fleet of 292 aircraft plus another 200 leased or chartered, so like you said, not actually as big an impact as I’d initially thought. The fact it happened at their main hub is probably a bigger factor.

They weren’t due to be retired till 2032 but replacing them with more leased aircraft till then could be an option depending on the outcome of the current investigation.
 
Penfold101 said:
They weren’t due to be retired till 2032 but replacing them with more leased aircraft till then could be an option depending on the outcome of the current investigation.
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There's also their planned retirement sequence, they are currently receiving regular deliveries of 767 and 777 which are supposed to be replacing their MD-11 and A-300 fleet. So they could temporarily stop retiring the A-300s to get the MD-11s gone faster, and buy some used 767/777 to accelerate the process (most of their MD-11 were bought used after they were retired form passenger service). I suppose it all depends how their bean counters look at it, but the insurance payout for the grounding is going to be a nice boon for them.
 
Juan at Blancolirio (usually reliable) thinks it was a failure of the turbine that catastrophically damaged the engine and sheared off the engine. The engine and pylon assembly then flew over the aircarft and in doing so the tail mounted engine ingested debris and began to surge. This happened just after rotation leaving no room to stop and not enough power or frust to get to any othe runway - as Juan says - doomed and nothin they could do.
 
I_M_Weasel said:
Juan at Blancolirio (usually reliable) thinks it was a failure of the turbine that catastrophically damaged the engine and sheared off the engine. The engine and pylon assembly then flew over the aircarft and in doing so the tail mounted engine ingested debris and began to surge. This happened just after rotation leaving no room to stop and not enough power or frust to get to any othe runway - as Juan says - doomed and nothin they could do.
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It seems plausible and Jaun is very well informed about these things so he’s probably correct in some fashion - I quote him a lot in these matters. It does seem incredible that a fan or turbine loss could cause severe enough vibrations to rip the pylon instantly off the wing without the engine going first, as fan losses, while not common as such, aren’t unknown but I’ve never seen one cause the engine/pylon to come off like that. Causing the centre engine to fail is ridiculously unlucky - the time it happened is just awful.
 
I'm sure he said the bolts attatching the pylon to the wing are designed to shear under intense vibration.

Penfold101 said:
It seems plausible and Jaun is very well informed about these things so he’s probably correct in some fashion - I quote him a lot in these matters. It does seem incredible that a fan or turbine loss could cause severe enough vibrations to rip the pylon instantly off the wing without the engine going first, as fan losses, while not common as such, aren’t unknown but I’ve never seen one cause the engine/pylon to come off like that. Causing the centre engine to fail is ridiculously unlucky - the time it happened is just awful.
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200sols said:
I'm sure he said the bolts attatching the pylon to the wing are designed to shear under intense vibration.
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They are, it’s just the level required that surprises me when fan blade loss events aren’t uncommon, so what was so bad about this one which caused the pylon to separate rather than the engine. Most of the isolation valves (fuel, hydraulics and air) are in the pylon so you’d rather that stayed with the aircraft.

Just my thoughts.
 
Penfold101 said:
It seems plausible and Jaun is very well informed about these things so he’s probably correct in some fashion - I quote him a lot in these matters. It does seem incredible that a fan or turbine loss could cause severe enough vibrations to rip the pylon instantly off the wing without the engine going first, as fan losses, while not common as such, aren’t unknown but I’ve never seen one cause the engine/pylon to come off like that. Causing the centre engine to fail is ridiculously unlucky - the time it happened is just awful.
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My memory is a bit fuzzy but I recall a very similar thing happening to a 747 (could have been an A380) in Europe years ago, one of the engines came off due to the sacrificial bolts breaking from vibration as intended however the engine launched forwards then destroyed the other engine on that wing causing serious damage to the aircraft and it's power/hydraulics.
 
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ubersonic said:
My memory is a bit fuzzy but I recall a very similar thing happening to a 747 (could have been an A380) in Europe years ago, one of the engines came off due to the sacrificial bolts breaking from vibration as intended however the engine launched forwards then destroyed the other engine on that wing causing serious damage to the aircraft and it's power/hydraulics.
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Definitely not an A380.

I think I remember reading somewhere (possibly from the other DC 10 incident) that the engine is designed to separate at the front mount first so that it falls away from the aircraft rather go upwards over the top, but that’s in ideal conditions where you have altitude.

On the runway, it doesn’t matter which it goes I suppose, especially after V1.
 
Penfold101 said:
They are, it’s just the level required that surprises me when fan blade loss events aren’t uncommon, so what was so bad about this one which caused the pylon to separate rather than the engine. Most of the isolation valves (fuel, hydraulics and air) are in the pylon so you’d rather that stayed with the aircraft.

Just my thoughts.
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Juan, thinks it is the compressor stage that failed rather than the fan - he showed a picture of the type of failure on a 767 that happened before V1 - does look very similar to the damage to the UPS engine.
 
ubersonic said:
Yeah I just double checked it was def a 747, El Al Flight 1862 in 1992.
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The Wikipedia article was interesting reading - it lists quite a few engine/pylon loss events in the early 707/747 days due to design flaws.


I_M_Weasel said:
Juan, thinks it is the compressor stage that failed rather than the fan - he showed a picture of the type of failure on a 767 that happened before V1 - does look very similar to the damage to the UPS engine.
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I watched that the other day - he’s talking about the turbine section at the back rather than the compressor section at the front (of which the fan is technically the first stage)

Apologies if I’m teaching anyone to suck eggs here - on triple spool engines, there are three stages where the fan at the front is the first stage, followed by an intermediate pressure stage compressor, then the high pressure stage. The IP and HP have multiple compressor stages but the fan (or LP) is just a single stage which is actually providing around 75% of the thrust of the engine as the cold stream, which bypasses the main core.

Each of these have a turbine section at the rear, connected by shafts running inside each other. The turbines take the energy out of the exhaust after combustion to drive the compressors, and only leave the remaining 25% providing any thrust (the hot stream), so they sit at hundreds of degrees and have a LOT of energy - if they let go, as in the 767 incident, there is no stopping them, to the extent that parts will go through the fuselage and embed themselves in the other engine:

AA 767 High Pressure Turbine Failure

a Gulfstream Jet sinks into the asphalt - apparently it was too heavy for the tarmac to support it.
www.dauntless-soft.com

The engine designers can make a fan case that will hold a blade-off event, but the turbine has too much energy:


A fan failure I would expect to be more like this:

https://www.bbc.co.uk/news/world-europe-41454712?app-referrer=deep-link
 
ubersonic said:
Now the FAA have grounded the MD-11 that may well be the planes done now regardless of what the investigation concludes.

As it's an FAA directive FedEx and UPS will now be able to claim off their insurance for the downtime which means from a purely financial POV as they were planning on scrapping the planes imminently anyway it makes sense to not even waste money doing the inspections (and any required remediations/modifications the FAA dictates) required to put them back into service and just accelerate the replacement program.
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Due to the infrequency of cargo flights relative to passenger flights they prefer to use second hand planes. So it won't be easy to accelerate that process.
 
Chuk_Chuk said:
Due to the infrequency of cargo flights relative to passenger flights they prefer to use second hand planes. So it won't be easy to accelerate that process.
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That's already been covered:
ubersonic said:
There's also their planned retirement sequence, they are currently receiving regular deliveries of 767 and 777 which are supposed to be replacing their MD-11 and A-300 fleet. So they could temporarily stop retiring the A-300s to get the MD-11s gone faster, and buy some used 767/777 to accelerate the process (most of their MD-11 were bought used after they were retired form passenger service). I suppose it all depends how their bean counters look at it, but the insurance payout for the grounding is going to be a nice boon for them.
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