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Enroute Airbus A380 wake flips Challenger business jet upside down

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Re: Enroute Airbus A380 wake flips Challenger business jet upside down

#81

Post by M_Grey »

wfunction wrote: post #71
M_Grey wrote: post #65

Earlier quoted context omitted.

In the 1-2 minutes between this thing booming past them, and being sent into a spin... you want them telling people to buckle up? That doesn't seem like the easier solution; it mostly sounds like a way to have people still hurrying in the aisles when it's too late.

Even half a minute minute is a hell of a lot of time and overwhelmingly better than no notice. Currently airplanes sometimes only turn on the sign after the turbulence has already started. Also, it's not like they never have no idea which airplanes are around them until they visually see the airplane. They could turn on the sign earlier if they know earlier.

I mean you say that, but wasn't this an accident predicated on not being aware of the positions of other planes? You're basically saying that we should plan for accidents, because wearing a seatbelt is somehow... what? Cumbersome?

If your neurological integrity isn't worth some hours in a seat, I guess that's your choice to make though.

Re: Enroute Airbus A380 wake flips Challenger business jet upside down

#82

Post by wfunction »

M_Grey wrote: post #81
wfunction wrote: post #71

Earlier quoted context omitted.

Even half a minute minute is a hell of a lot of time and overwhelmingly better than no notice. Currently airplanes sometimes only turn on the sign after the turbulence has already started. Also, it's not like they never have no idea which airplanes are around them until they visually see the airplane. They could turn on the sign earlier if they know earlier.

I mean you say that, but wasn't this an accident predicated on not being aware of the positions of other planes? You're basically saying that we should plan for accidents, because wearing a seatbelt is somehow... what? Cumbersome? If your neurological integrity isn't worth some hours in a seat, I guess that's your choice to make though.

> I mean you say that, but wasn't this an accident predicated on not being aware of the positions of other planes?

Uh, no? "an Airbus A380-800 was observed by the crew passing 1000 feet above" http://avherald.com/h?article=4a5e80f3

> You're basically saying that we should plan for accidents

Yes, whenever possible. It should make sense, really.

> because

...because it's sometimes possible and predictable, in which case it logically makes sense to plan for it.

> wearing a seatbelt is somehow... what? Cumbersome?

Not because of that. But yes, it is cumbersome. Makes it harder to relax, sleep, get up, etc... is this really that shocking to you?

Re: Enroute Airbus A380 wake flips Challenger business jet upside down

#83

Post by simion314 »

nether wrote: post #41
Zak wrote: post #39

Earlier quoted context omitted.

Wings generate lift primarily by deflecting air downward. There is an area of low pressure over the wing where air is taking a longer path than under the wing, but that is only responsible for a small fraction of the lift.

"Longer path" has no bearing on reality. A flat plate can generate plenty of lift even with both sides the same. It's also hard to define "path," as the air starts convecting well ahead of the wing in subsonic flow.

If I remember right the "longer path" thing was in Encarta, there was a guy that used Encarta to prove to me that the theory is right and I believed it m it made sense I am wrong and not the encyclopedia.

Re: Enroute Airbus A380 wake flips Challenger business jet upside down

#84

Post by M_Grey »

wfunction wrote: post #82
M_Grey wrote: post #81

Earlier quoted context omitted.

I mean you say that, but wasn't this an accident predicated on not being aware of the positions of other planes? You're basically saying that we should plan for accidents, because wearing a seatbelt is somehow... what? Cumbersome? If your neurological integrity isn't worth some hours in a seat, I guess that's your choice to make though.

> I mean you say that, but wasn't this an accident predicated on not being aware of the positions of other planes? Uh, no? "an Airbus A380-800 was observed by the crew passing 1000 feet above" http://avherald.com/h?article=4a5e80f3 > You're basically saying that we should plan for accidents Yes, whenever possible. It should make sense, really. > because ...because it's sometimes possible and predictable, in which cas…

"According to information The Aviation Herald received on March 4th 2017 the CL-604 passed 1000 feet below an Airbus A380-800 while enroute over the Arabian Sea, when a short time later (1-2 minutes)"

They saw the plane, and 1-2 minutes later... bang. We already went over this.

Re: Enroute Airbus A380 wake flips Challenger business jet upside down

#85

Post by davidwihl »

clueless123 wrote: post #16
clueless123 wrote: post #15

Big problem is the use of autopilot navigation locked to the GPS route.. this pretty much guarantees that you will fly right below the wake of the above plane on the same route! (Before GPS it will be very odd to flight exactly the same path) ..

Few years ago, an embraer actually cut another's plane wing off for the exact same reason. (They were flying at the wrong altitude though)

They were not flying at the wrong altitude - ATC cleared both aircraft to the same altitude on a collision course.

Re: Enroute Airbus A380 wake flips Challenger business jet upside down

#86

Post by M_Grey »

fulafel wrote: post #72
M_Grey wrote: post #64

Earlier quoted context omitted.

There's a reason that people with money and power don't always experience good outcomes. Sure, you can do what you like on your jet, and therefore expose yourself to risk that most people never experience. Likewise skiing off-piste or a number of other equally silly activities that you can do, but absolutely shouldn't.

Probably they have a different idea about risk management than more risk-averse people. Worrying a lot about very low probability events is not compatible with the risk-taking typically required to make a lot of money. After all millionaires are largely a "survivor club" filtered from high risk appetite workaholics.

I don't know about that. I think mostly it has to do with having the power to pick and choose critical service providers, bully them, etc. If Michael Jackson and Steve Jobs had not been as wealthy and powerful as they had been, they would also both probably be alive.

Neither has much to do with being risk-takers, although you might be right that a higher arousal threshold desensitized them to risk. It may also be that people used to winning, on some level, expect to keep winning. Either way, we're not just talking about Fortune 500 C-levels here, plenty of people with loads of money and power did nothing to get it, and have no special qualities associated with that ability to get it.

They still often have bad outcomes.

Re: Enroute Airbus A380 wake flips Challenger business jet upside down

#87

Post by cyberferret »

Zak wrote: post #39
cyberferret wrote: post #36

Earlier quoted context omitted.

If you recall Boyle's Law from high school physics - Temperature is proportional to pressure. Aircraft wings generate an intense area of low pressure over the top of the wing (which is what essentially generates the lift). This low pressure area is magnified when flaps and slats are deployed. On a humid day, the lowering of the pressure over the wings can basically force the air temperature at that point to lower and…

Wings generate lift primarily by deflecting air downward. There is an area of low pressure over the wing where air is taking a longer path than under the wing, but that is only responsible for a small fraction of the lift.

Or we can just go to the demonstration that our flight instructor did in the first 5 minutes of our Aerodynamics 101 lectures.

Get a piece of A4 or Letter sized paper and try this experiment with it [0]. For best effect, hold both the edges closest to you in each hand and twist the front edge downwards to keep it straight and prevent the paper twisting which could inadvertently straighten it. (i.e. Not with one hand like he is doing in the video).

The Bernoulli principle with postulates the Venturi effect is about the only theory that can explain why the trailing edge of the paper moves UPWARDS when you blow across the top of the curved paper.

[0] - https://www.youtube.com/watch?v=R3VVbajPqc0

Re: Enroute Airbus A380 wake flips Challenger business jet upside down

#88

Post by wfunction »

M_Grey wrote: post #84
wfunction wrote: post #82

Earlier quoted context omitted.

> I mean you say that, but wasn't this an accident predicated on not being aware of the positions of other planes? Uh, no? "an Airbus A380-800 was observed by the crew passing 1000 feet above" http://avherald.com/h?article=4a5e80f3 > You're basically saying that we should plan for accidents Yes, whenever possible. It should make sense, really. > because ...because it's sometimes possible and predictable, in which cas…

"According to information The Aviation Herald received on March 4th 2017 the CL-604 passed 1000 feet below an Airbus A380-800 while enroute over the Arabian Sea, when a short time later (1-2 minutes)" They saw the plane, and 1-2 minutes later... bang. We already went over this.

> They saw the plane, and 1-2 minutes later... bang. We already went over this.

We did, that's why it made zero sense that you said this was predicated on not being aware of the positions of other planes. They were aware of this a full 1-2 minutes earlier at least. They could've turned on the sign. The solution was totally implementable.

Re: Enroute Airbus A380 wake flips Challenger business jet upside down

#89

Post by snowwrestler »

cyberferret wrote: post #87
Zak wrote: post #39

Earlier quoted context omitted.

Wings generate lift primarily by deflecting air downward. There is an area of low pressure over the wing where air is taking a longer path than under the wing, but that is only responsible for a small fraction of the lift.

Or we can just go to the demonstration that our flight instructor did in the first 5 minutes of our Aerodynamics 101 lectures. Get a piece of A4 or Letter sized paper and try this experiment with it [0]. For best effect, hold both the edges closest to you in each hand and twist the front edge downwards to keep it straight and prevent the paper twisting which could inadvertently straighten it. (i.e. Not with one hand…

Sure but now try the same thing with a piece of metal.

No one questions whether the Bernoulli and Venturi effects actually exist. But airplanes are heavy and it's pretty obvious that the Bernoulli effect does not produce sufficient lift by itself.

As proof that most of the lift comes from deflecting air, I offer the fact that airplanes can fly upside down.

Re: Enroute Airbus A380 wake flips Challenger business jet upside down

#90

Post by wwalser »

nunez wrote: post #67

I thought controllers space aircraft based on their takeoff weight for this reason. Is this true? A380s are HUGE, so this isn't surprising. wake turbulence is a killer

The (current) top thread in the comments section references the reduced vertical separation minima (RVSM): https://en.wikipedia.org/wiki/Reduced_vertical_separation_mi...

It appears that there is a section of air between 29,000ft and 41,000ft, where flights are allowed to be closer than is normally allowed. Instead of 2,000ft apart, they are allowed to fly 1,000ft apart. In order to operate continually in this airspace, a plane must be "RVSM approved". Otherwise they have to either request special permission or make a continuous climb through said airspace while complying with their usual 2,000ft requirements.

The article mentions that the A380 and Challenger 604 were 1,000ft apart. So, I would assume they were both RVSM approved. This event could call the RVSM into question.

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