Comment by justsid
1 day ago
The damage on the ground is scary to look at. I think the only silver lining here is that it was "just" a sparser industrial area and there weren't any homes. I'm really curious about what the investigation will reveal in a few months. This doesn't look like a "regular" engine fire from a bird strike or so, you would normally expect the flames to come out the back and not over the wing. And at least in theory the MD-11 should be flyable with just two engines, although flames on a wing is probably "really really bad" just by itself already. Too early to speculate about what happened though.
Zoning guidance generally prohibits land use near an airport that has a high density of people, precisely to limit casualties during an event like this. Industrial would be permitted while residential and commercial use is not.
Scarily there are communities that have ignored such logic and permitted dense residential development right next to an airport.
UPS actually bought and destroyed thousands of homes near their end of the airport about 20 years ago, under the guise of 'noise', but realistically for expansion of warehousing. Now, I guess I feel slightly less upset by that (my childhood home was one of them).
Jets are also simply too loud for homes under the takeoff path in standard use. There’s what amounts to a ghost town next to LAX due to this and the history of the airport.
https://en.wikipedia.org/wiki/Palisades_del_Rey,_California
Burbank Airport has quiet hours and has left a bunch of commercially zoned area under that takeoff path.
I’m in Atlanta now and they bought up a lot of land around the airport when redeveloping it and do similar zoning tricks for the buffer. One of the buffer zones is the Porsche Experience. It’s loud as heck when you’re on the part of the track closest but not bad where the corporate HQ and paddock is
I just looked that up (Atlanta) on https://noise-map.com/ and man, that's way not enough zoning tricking in my book. Not that it's much different in other cities (or countries).
I grew up 3 miles (as the crow flies) from JFK Runway 31 R / 13 L in Cedarhurst, New York
https://www.google.com/maps/dir/Cedarhurst,+NY+11516/John+F....
Meanwhile, ORD is surrounded by residential areas and they're building a new tollway perpendicular to the runways
It's amazing that towns don't see this sort of thing and think "huh maybe it's not a good idea to put apartments right on top of an airport", but I guess they don't. Longmont is in trouble with the FAA because they OKed a bunch of apartments right at the end of Vance Brand that would be right in the path of aircraft struggling to gain altitude out of the airport. Naturally there's a vocal contingent of people around here that think this is the airport's problem and not the town or greedy developers, and that all the airports (except DIA) should be shut down.
Fresno here. If this had happened at FAT (FYI now? We have dumb names) the casualties would've easily hit three digits from initial impact, and then whatever else burned afterwards because CA==tinderbox.
Same with SJC, no matter which direction they were taking off.
You can always come up with some pretext to justify things by ignoring the other side of the equation.
How many lives do the man hours spent commuting, or toiling away to afford higher rents waste?
IDK how the math pencils out, but an attempt ought to be made before drawing conclusions.
None? Nobody puts airports inside city centers and metro areas don’t just have dense urban housing. The common solution in many land strapped cities is for airports to rout aircraft over water often by building airports on reclaimed land.
What generally gets areas in trouble is locations that used to be a good get worse as aircraft get larger and the surroundings get built up. The solution is to send larger airplanes to a new airport, but it’s not free and there’s no clear line when things get unacceptably dangerous.
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Midway comes to mind: https://maps.app.goo.gl/GRUXJVdUPQMWkZNU6
Probably also due to noise.
Yeah I was going to say, that sounds like a much more salient reason not to live near an airport than the possibility of that rare crash.
The pollution and noise probably has health effects many times more significant than the sum of extremely rare crashes like these.
> Zoning guidance generally prohibits land use near an airport that has a high density of people
Queens, NY has entered the chat…
>Queens, NY has entered the chat…
You’re correct, but at least LaGuardia airport generally has takeoffs over water.
LaGuardia aircraft landings may happen over dense apartment buildings, but less likely for catastrophic damage (glide path, less fuel, engines are <10% throttle, etc)
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Some of the larger townships in Cape Town are right in the flight path too. Not many white people there either.
An accident on takeoff means full tanks - some 38000 gallons(?) spread along the site like a napalm strike.
A particularly large amount of fuel because it was flying to Honolulu
A particularly large amount of fuel also because it was loaded with heavy cargo intended to make it all the way to Honolulu.
> And at least in theory the MD-11 should be flyable with just two engines
Flying with two engines and taking off without an engine in a loaded aircraft are two very different things. A lot more thrust is needed during takeoff than after.
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 speed (past a certain speed, you only abort if the aircraft is literally unflyable - for everything else, you take the aircraft & emergency into the air and figure it out there). 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.
> 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.
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Every multi-engine airliner is designed to be able to take off safely even if an engine fails at a critical moment. What might have happened in this case is that the mechanism of failure of one engine caused damaged or interfered with the operation of another engine (via smoke, debris, etc.), and taking off with two engines degraded is not part of the design criteria.
Some engine failures can't be contained within the cowling, like turbine disc rupture. Probably something like this happened where fragments punctured the surrounding wing structure and/or fuel tanks.
I do think 'engine fails' and 'engine has left the building' are two different categories of problems. Even if the rear engine was working I'm going to assume this craft would have crashed, probably just farther down range.
I specifically remember watching a flight test doing an aggressive takeoff and having the voiceover say that aircraft (two engine) need to have enough power to take off full with one engine. And so can take off very steeply empty with two engines. Would that not also be the case for these planes?
Yes, planes are designed to be able to take off with a lost engine. Usually this will extend the roll a bit because the speeds are different for engine out operations. This isn't the first MD-11 with an engine out take off, 5 years ago a FedEx MD-11 took off with a failure in the left engine[1]. Slightly different case, obviously, but it's certainly something that is accounted for when designing planes.
[1] https://www.avherald.com/h?article=4dfd50b9&opt=0%20
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All planes are definitely capable of taking off safely even if they lose an engine at the worst time. Whatever happened here, I would be shocked if lack of thrust in the 2 remaining engines was a significant factor unless someone really screwed up the load calculations and they were overweight for conditions.
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The ground damage in the recent North Philadelphia Airport crash was only due to a chartered jet, but it practically wiped out a residential city block.
Looks like a compressor stall on number two engine two seconds into the video.
I don’t know, that looks like a lot more than just a stall. There was a ton of flame that looked like it was coming out of the front or top of the engine, rather than just something shooting out the back.
I think you're looking at the left wing (number 1) engine; GP is talking about either the tail or right wing engine. (I think tail is number 2 on MD-11.) There's a brief explosion visible through the smoke at about 1-2 seconds in, to the right of the engine visibly on fire; that's probably what he's talking about.
Freeze frame: https://imgur.com/a/c3h8Qd3
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I would say it does not, in fact, look like a compressor stall. It looks very much like an uncontained disassembly, presumably from fan blades that suffered a catastrophic failure and broke up in a way that exceeded the limits of the engine's containment.
Obviously impossible to tell from some cell phone type videos. Being struck by something is also possible. But it sure does look like an uncontained engine failure.
I think you're looking at engine number 1, while GP is talking about engine 2.
https://news.ycombinator.com/item?id=45818448