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UPS plane crashes near Louisville airport

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Re: UPS plane crashes near Louisville airport

#51

Post by octaane »

cityofdelusion wrote: post #45
octaane wrote: post #27

This is probably the worst way a plane could go down in terms of damage caused. Maximum effect in term of damage. Cargo plane apparently reached V1 (go/no go speed) on the runway, and suffered a catastrophic engine failure. They passed V1, so they knew they were going down. Engine was shedding large debris, including the housing (!!!) which is a shrapnel shield. They were on fire just as they reached V1. Plane was fu…

Standard procedure at V1 is commit to the takeoff and diagnose the problem in-air. Much of your comment is pure speculation until flight data recorders come back, we have no idea what the crew was thinking or what issues they were even aware of.

You're 100% right, and that's exactly what I'm getting at - they hit V1 and were aware they had a serious problem, but couldn't abort.

As far as the rest of my comment - watch the videos that I linked.

Re: UPS plane crashes near Louisville airport

#52

Post by positron26 »

octaane wrote: post #35
gizmo686 wrote: post #32

Earlier quoted context omitted.

> they tried to take off instead of accelerate past the runway at ground level Do runways have some sort of barrier between them and the next "important" thing. It seems like that would be prudent both for cases like this, and breaking failures following landings.

Unless you have a berm several dozen meters high with a 100 meter base, you ain't stopping something like this from a physics standpoint unfortunately. Many airports have this problem. The recent korean air disaster which echos this is another example. BTW, this is why most airports, if possible, point out to sea...

There is a dead zone between rejection and successful take-off speeds. We see it hit too often.

I think pilot training is playing a factor. A normal rotation kills too much energy. One engine can climb when you have some airspeed and get clean, but if you lose too much energy on rotation, the inefficiency of the AoA for the rest of the short flight means that engine can no longer buy you any up. I've seen too many single-engine planes going down while trying to pitch up the whole way down.

So, less aggressive single-engine rotations and energy absorbers at the ends of runways that can't get longer. This seems like the kind of thing where we do it because it removes a significant cause of people dying.

Just watched this angle a few more times: https://x.com/BNONews/status/1985845907191889930

Another crash video shows the aircraft clearly descending before colliding with anything. It manages to go up a bit, so it's fast enough to get airborne. The normal looking rotation kills too much energy. The plane is then too inefficient to maintain speed. AoA goes up while energy goes down. Power available goes negative and then it's over.

Re: UPS plane crashes near Louisville airport

#53

Post by octaane »

chzblck wrote: post #46
octaane wrote: post #27

This is probably the worst way a plane could go down in terms of damage caused. Maximum effect in term of damage. Cargo plane apparently reached V1 (go/no go speed) on the runway, and suffered a catastrophic engine failure. They passed V1, so they knew they were going down. Engine was shedding large debris, including the housing (!!!) which is a shrapnel shield. They were on fire just as they reached V1. Plane was fu…

Sorry for ignorance but why is the right thing to continue to take off with an engine on fire?

To avoid mass casualties at the end of the runway - on the road, or the buildings that the runway points to. Check the layout on google maps.

More specifically, V1 is the max speed at which you're about to take off, but you can still abort from. They hit that max speed and realized there was a major problem that hypothetically, they could have slowed down from, but realistically was not possible. They had no choice.

Re: UPS plane crashes near Louisville airport

#54

Post by atrus »

chzblck wrote: post #46
octaane wrote: post #27

This is probably the worst way a plane could go down in terms of damage caused. Maximum effect in term of damage. Cargo plane apparently reached V1 (go/no go speed) on the runway, and suffered a catastrophic engine failure. They passed V1, so they knew they were going down. Engine was shedding large debris, including the housing (!!!) which is a shrapnel shield. They were on fire just as they reached V1. Plane was fu…

Sorry for ignorance but why is the right thing to continue to take off with an engine on fire?

It was at a point where they were going to fast to stop or land safely. At that point you're just trying to pick the best place to crash.

Re: UPS plane crashes near Louisville airport

#55

Post by positron26 »

Jtsummers wrote: post #20
filleduchaos wrote: post #19

Earlier quoted context omitted.

Taking off with one engine inoperative (on a multi-engine aircraft, obviously - you aren't going to get anywhere with your only engine gone) is completely normal/within design parameters, albeit undesirable. In fact, it being normal almost certainly contributed to the scale of this accident, since a single engine failure during the takeoff roll isn't considered enough of an emergency to reject the takeoff at high spe…

> The crew wouldn't have had any way to know that one of their engines had not simply failed, but was straight-up gone with their wing on fire to boot. I don't know about the MD-11 itself, but other aircraft from that time period have sensors to detect and report overheat and fire in various parts of the aircraft, including engines and wings.

This puts an impractical amount of faith in the sensor wiring when the whole pylon and cowling are shredded.

Re: UPS plane crashes near Louisville airport

#56

Post by octaane »

atrus wrote: post #54
chzblck wrote: post #46

Earlier quoted context omitted.

Sorry for ignorance but why is the right thing to continue to take off with an engine on fire?

It was at a point where they were going to fast to stop or land safely. At that point you're just trying to pick the best place to crash.

[flagged]

Re: UPS plane crashes near Louisville airport

#57

Post by [deleted] »

chzblck wrote: post #46
octaane wrote: post #27

This is probably the worst way a plane could go down in terms of damage caused. Maximum effect in term of damage. Cargo plane apparently reached V1 (go/no go speed) on the runway, and suffered a catastrophic engine failure. They passed V1, so they knew they were going down. Engine was shedding large debris, including the housing (!!!) which is a shrapnel shield. They were on fire just as they reached V1. Plane was fu…

Sorry for ignorance but why is the right thing to continue to take off with an engine on fire?

[deleted]

Re: UPS plane crashes near Louisville airport

#59

Post by TylerE »

gizmo686 wrote: post #32
octaane wrote: post #27

This is probably the worst way a plane could go down in terms of damage caused. Maximum effect in term of damage. Cargo plane apparently reached V1 (go/no go speed) on the runway, and suffered a catastrophic engine failure. They passed V1, so they knew they were going down. Engine was shedding large debris, including the housing (!!!) which is a shrapnel shield. They were on fire just as they reached V1. Plane was fu…

> they tried to take off instead of accelerate past the runway at ground level Do runways have some sort of barrier between them and the next "important" thing. It seems like that would be prudent both for cases like this, and breaking failures following landings.

Security/debris fencing yes, but that's like, orders of magnitude short of what would stop the amount of energy we're talking about here.

You also don't particularly want it to be catastrophically effective as there are real world cases where planes have clipped the fence and then NOT gone on to crash, or at least to crash in a fairly controlled manner with the majority onboard surviving. Hitting a brick wall at 180mph is going to have a 0% survival rate.

Re: UPS plane crashes near Louisville airport

#60

Post by Jtsummers »

positron26 wrote: post #55
Jtsummers wrote: post #20

Earlier quoted context omitted.

> The crew wouldn't have had any way to know that one of their engines had not simply failed, but was straight-up gone with their wing on fire to boot. I don't know about the MD-11 itself, but other aircraft from that time period have sensors to detect and report overheat and fire in various parts of the aircraft, including engines and wings.

This puts an impractical amount of faith in the sensor wiring when the whole pylon and cowling are shredded.

I don't know what the MD-11 would have had, again I didn't work on it. But the systems used for other aircraft would have reported an alarm based on what I saw in the video, at least they were designed to do that. The LRU receiving the sensor inputs wouldn't typically be in the wing and would be able to continue reporting the alarm condition even if the sensors fail. In fact, the lack of current from the sensor (for the systems I worked on) would have been enough to trigger the alarm if the sensor were completely eliminated.
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