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Lufthansa jet and drone nearly collide near LAX

latimes.com

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Re: Lufthansa jet and drone nearly collide near LAX

#21

Post by nether »

iofj wrote: post #13
DataJunkie wrote: post #10

Earlier quoted context omitted.

Disclaimer: Aviation hobbyist but not an expert. It depends on the size of the drone and where it hits. I am not sure how large these drones are, but if they have the mass of a flock of large seagulls, say, it could disable an engine (like the US Airways jet). A collision with a wing could cause substantial damage to the wing which would change the aerodynamics, and that could be potentially dangerous at low altitude…

The airflow would be trying to prevent a collision with the front of the wing, and a drone would simply go where the wind blows. Which is to say if a drone flew straight for an airplane wing, it would fly around the wing and suddenly explode in the massive turbulence behind the wing. This would look very surprising because to the naked eye there is nothing behind the wing. Hitting the fuselage, or entering an engine…

There isn't really any "turbulence" behind any modern wing in typical flight regimes. They're very low drag, so flow off the trailing edge is as smooth as the upstream flow.

Re: Lufthansa jet and drone nearly collide near LAX

#22

Post by tzs »

iofj wrote: post #13
DataJunkie wrote: post #10

Earlier quoted context omitted.

Disclaimer: Aviation hobbyist but not an expert. It depends on the size of the drone and where it hits. I am not sure how large these drones are, but if they have the mass of a flock of large seagulls, say, it could disable an engine (like the US Airways jet). A collision with a wing could cause substantial damage to the wing which would change the aerodynamics, and that could be potentially dangerous at low altitude…

The airflow would be trying to prevent a collision with the front of the wing, and a drone would simply go where the wind blows. Which is to say if a drone flew straight for an airplane wing, it would fly around the wing and suddenly explode in the massive turbulence behind the wing. This would look very surprising because to the naked eye there is nothing behind the wing. Hitting the fuselage, or entering an engine…

30 seconds of Googling turns up numerous examples of bird strikes on the leading edge of wings, some with very substantial damage.

Why would airflow around the wing keep a drone from hitting it but not a bird?

Re: Lufthansa jet and drone nearly collide near LAX

#23

Post by nether »

cptskippy wrote: post #11
szx wrote: post #9

This might be a naive question, but what would happen if a hobby drone collided with a jet? As long as it doesn't hit the engines, wouldn't the damage be negligible?

I would imagine hitting the engine is probably the safest thing that could happen. The engines are made of titanium alloys and designed to not fail catastrophically. The rest of the aircraft is made of soft materials by comparison.

Ti isn't an exceptionally hard metal, it's just very strong for its weight. So the fan (and the rest of the engine) would take significant damage.

Re: Lufthansa jet and drone nearly collide near LAX

#24

Post by MaxScheiber »

hanniabu wrote: post #17
DataJunkie wrote: post #10

Earlier quoted context omitted.

Disclaimer: Aviation hobbyist but not an expert. It depends on the size of the drone and where it hits. I am not sure how large these drones are, but if they have the mass of a flock of large seagulls, say, it could disable an engine (like the US Airways jet). A collision with a wing could cause substantial damage to the wing which would change the aerodynamics, and that could be potentially dangerous at low altitude…

Anybody know what the protocol is in the event of a blown out windshield/windscreen? Would the pilots be sucked out even at a low altitude such as 5k feet? Whether they are our aren't, how will the plane be landed?

https://en.wikipedia.org/wiki/British_Airways_Flight_5390

Re: Lufthansa jet and drone nearly collide near LAX

#25

Post by nether »

tzs wrote: post #22
iofj wrote: post #13

Earlier quoted context omitted.

The airflow would be trying to prevent a collision with the front of the wing, and a drone would simply go where the wind blows. Which is to say if a drone flew straight for an airplane wing, it would fly around the wing and suddenly explode in the massive turbulence behind the wing. This would look very surprising because to the naked eye there is nothing behind the wing. Hitting the fuselage, or entering an engine…

30 seconds of Googling turns up numerous examples of bird strikes on the leading edge of wings, some with very substantial damage. Why would airflow around the wing keep a drone from hitting it but not a bird?

Nothing. Upstream flow stagnates at the leading edge, excess bug splatter there attests to that.

Re: Lufthansa jet and drone nearly collide near LAX

#26

Post by [deleted] »

tanishq1 wrote: post #12
cptskippy wrote: post #11

Earlier quoted context omitted.

I would imagine hitting the engine is probably the safest thing that could happen. The engines are made of titanium alloys and designed to not fail catastrophically. The rest of the aircraft is made of soft materials by comparison.

And even in the event of an engine failure, they could still probably land safely.

[deleted]

Re: Lufthansa jet and drone nearly collide near LAX

#27

Post by beachstartup »

for those of you who don't know the geography of los angeles, LAX is basically surrounded on 3 sides by dense urban buildup, and then the ocean. the flight path for landing goes over the entire city including downtown, and the runways are sandwiched by freeways and major boulevards on all sides. the approach at night is quite dramatic visually, if you're lucky enough to snag a window seat. i very much enjoy trying to identify everything as i fly over.

it truly is "the motherboard". people who have never flown in before are shocked to see it. it's something else. the only thing that compares in the US is probably chicago, but it's not the same scale, and LA also has geography which adds to the visual drama. tokyo is similar but not quite the same kind of approach. i don't recall any airport in europe even approaching the visual appeal of the LAX approach. i've never flown into mexico city, from looking at maps it's probably close, but physically it's nowhere near as large as the LA metro (including IE, OC, etc.). LA is huge. yuuuuuge.

it is bounded by office highrises, datacenters, hotels, and housing. in my opinion it's likely the most dangerous airport in the US in terms of potential damage from a non-terrorist crash. i can't think of any airports in the US that are quite the same. it's currently the global #5 volume airport but the insane amount of traffic from asia will probably make it #1 within a few years. there is a major expansion and renovation project happening right now.

Re: Lufthansa jet and drone nearly collide near LAX

#29

Post by throwaway_xx9 »

nether wrote: post #21
iofj wrote: post #13

Earlier quoted context omitted.

The airflow would be trying to prevent a collision with the front of the wing, and a drone would simply go where the wind blows. Which is to say if a drone flew straight for an airplane wing, it would fly around the wing and suddenly explode in the massive turbulence behind the wing. This would look very surprising because to the naked eye there is nothing behind the wing. Hitting the fuselage, or entering an engine…

There isn't really any "turbulence" behind any modern wing in typical flight regimes. They're very low drag, so flow off the trailing edge is as smooth as the upstream flow.

Well, except for those pesky wingtip vortices that can down a smaller airliner.

Re: Lufthansa jet and drone nearly collide near LAX

#30

Post by nightski »

nether wrote: post #21
iofj wrote: post #13

Earlier quoted context omitted.

The airflow would be trying to prevent a collision with the front of the wing, and a drone would simply go where the wind blows. Which is to say if a drone flew straight for an airplane wing, it would fly around the wing and suddenly explode in the massive turbulence behind the wing. This would look very surprising because to the naked eye there is nothing behind the wing. Hitting the fuselage, or entering an engine…

There isn't really any "turbulence" behind any modern wing in typical flight regimes. They're very low drag, so flow off the trailing edge is as smooth as the upstream flow.

This was near landing, so I assume flaps were deployed. That changes things a bit.
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