Enroute Airbus A380 wake flips Challenger business jet upside down • Hacker News Board

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

#111

Post by wfunction » Fri, Mar 17, 2017, 6:58 AM UTC

sulam wrote: post #109

wfunction wrote: post #56

Earlier quoted context omitted.

While I agree with the general sentiment, to be honest there are easier solutions here. They could've just turned on the sign as soon as they saw the A380 so that people could fasten their seatbelts then. And then turned off the sign when the threat was gone. You don't need a cannon to kill a fly.

Surely this entire event is notable because no one had any idea that this might happen. Seat belts or not, 3 or more rolls and a written off airplane is an outcome they would have avoided if they'd known it had even a remote chance of happening.

You'd think so, but from now on do you think planes are going to stop flying under each other or try to maneuver out of the way when this happens inadvertently? I really wish they do, but that's not the impression I got from the article. All I saw was "ATC all around the globe have recently been instructed to exercise particular care with A380s crossing above other aircraft. The Aviation Herald had already reported a number of Wake Turbulence Encounters involving A380s before", which is kind of vague and doesn't quite give me the impression they're necessarily (literally) going to go out of their ways for this if it has a chance of happening.

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

#112

Post by webignition » Fri, Mar 17, 2017, 7:01 AM UTC

ghshephard wrote: post #96

M_Grey wrote: post #63

Earlier quoted context omitted.

When I was in single digits, my mother and I were coming home from an international flight and the plane was struck by lightning. We lost a bit of altitude (felt like a TON of altitude subjectively), and yeah... it was a damned good thing we'd all been told to keep those seatbelts on. It was literally the difference between seconds of terror, and someone being seriously injured.

Using that philosophy, then anyone riding a bicycle, even if they aren't going at high-speed on road, should wear a helmet "just in case" there is an accident to protect their skull? There is a balance between annoyance and utility. I personally have no problem wearing a belt for the entire flight, including while sleeping. But I'm not to dismayed by those who leave it off, walk around the cabin, go hang out near the…

Yes, you should absolutely wear a helmet when riding a bicycle at low speeds.

Your skull is vulnerable to impacts at speeds that are relatively low compared to full-speed cycling.

On a few occasions I've witnessed a cyclist panic and wobble after being passed far too closely by a car traveling far too fast for such a manoeuvre. This has caused such cyclists to wobble, inadvertently clip the curb and mount the pavement, fall off sideways and subsequently strike their head on a nearby wall whilst falling.

The resulting injury can be very harmful.

Another example of slow-speed head injury: off-road biking down a very steep incline with a loose surface. I've seen people fall and tumble at almost stationary speeds.

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

#113

Post by andruby » Fri, Mar 17, 2017, 7:03 AM UTC

redler wrote: post #99

komali2 wrote: post #94

Earlier quoted context omitted.

I feel like Steve Jobs is an odd choice... He turned down treatment I thought?

He wasted precious time indulging quackery.

But even if he was't rich I'm pretty sure he would have done the same.

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

#114

Post by adventured » Fri, Mar 17, 2017, 7:05 AM UTC

redler wrote: post #99

komali2 wrote: post #94

Earlier quoted context omitted.

I feel like Steve Jobs is an odd choice... He turned down treatment I thought?

He wasted precious time indulging quackery.

Which more likely has absolutely nothing to do with him being rich. His quackery behavior was very high on the scale before he was rich post Apple IPO.

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

#115

Post by closeparen » Fri, Mar 17, 2017, 7:08 AM UTC

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.

>millionaires are largely

Pedantic, but. Families with $1m net worth are largely late-middle-aged (newly retired) salary workers with paid-off mortgages on their median-priced houses in suburban flyover country, plus ~40 years of 401k contributions and capital gains.

They drive Toyotas and fly economy for their 1-2 yearly vacations because that's what left when the 15% 401k contribution, mortgage on 3bd house, children's educations, and groceries are paid for.

Think teachers, bureaucrats, journalists (pre-internet), scientists, engineers, doctors, and lawyers, in roughly ascending order. What you'd call the upper middle class.

There are about 8 million millionaire households in the US as of 2016 [0].

Private jets are more a feature of the Fortune 500 CEO Davos-going class. $1 million in income maybe, very different from $1m net worth. It's not generally useful to conflate these wildly different wealth levels under the same terminology.

[0] https://en.wikipedia.org/wiki/Millionaire

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

#116

Post by ajdlinux » Fri, Mar 17, 2017, 7:09 AM UTC

ghshephard wrote: post #96

M_Grey wrote: post #63

Earlier quoted context omitted.

When I was in single digits, my mother and I were coming home from an international flight and the plane was struck by lightning. We lost a bit of altitude (felt like a TON of altitude subjectively), and yeah... it was a damned good thing we'd all been told to keep those seatbelts on. It was literally the difference between seconds of terror, and someone being seriously injured.

Using that philosophy, then anyone riding a bicycle, even if they aren't going at high-speed on road, should wear a helmet "just in case" there is an accident to protect their skull? There is a balance between annoyance and utility. I personally have no problem wearing a belt for the entire flight, including while sleeping. But I'm not to dismayed by those who leave it off, walk around the cabin, go hang out near the…

That happens to be the justification that my country uses to make bicycle helmets mandatory (though there's significant debate about whether it's actually helped reduce injury rates, and it fairly clearly depresses overall rates of cycling versus other modes of transport).

I think the cost of wearing an aircraft seatbelt while you happen to be seated is rather lower than the cost of having to wear a bicycle helmet, though.

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

#117

Post by cjrp » Fri, Mar 17, 2017, 7:09 AM UTC

dingaling wrote: post #92

antubbs wrote: post #61

Earlier quoted context omitted.

Eh. e.g. the north atlantic tracks have been around since the 1960s. GPS wasn't available to the public until Korean Air Lines Flight 007 in the 1980s.

The OP means that satnav ensures that two aircraft on a reciprocal or identical track will now pass over one another, whereas there used to be navigational slop that would give some unintentional but useful lateral displacement.

Ironic that you should use the term 'slop', since that's exactly how they avoid flying the same route across the Atlantic tracks for example (Strategic Lateral Offset Procedure).

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

#118

Post by andruby » Fri, Mar 17, 2017, 7:09 AM UTC

wfunction wrote: post #111

sulam wrote: post #109

Earlier quoted context omitted.

Surely this entire event is notable because no one had any idea that this might happen. Seat belts or not, 3 or more rolls and a written off airplane is an outcome they would have avoided if they'd known it had even a remote chance of happening.

You'd think so, but from now on do you think planes are going to stop flying under each other or try to maneuver out of the way when this happens inadvertently? I really wish they do, but that's not the impression I got from the article. All I saw was "ATC all around the globe have recently been instructed to exercise particular care with A380s crossing above other aircraft. The Aviation Herald had already reported a…

Yes. I think that all small aircraft pilots will read/hear about this story. They might even practice the event in simulators.

And all of them will avoid passing under a large aircraft at 180 degrees.

Source: my father is an airline pilot and they always take the time to learn from severe incidents.

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

#119

Post by tbabb » Fri, Mar 17, 2017, 7:10 AM UTC

EGreg wrote: post #103

"until the crew was able to recover the aircraft exercising raw muscle force" Any more info on that??

Under normal flight conditions, the aircraft's engine supplies hydraulic power to the flight controls (flaps, ailerons, elevator), like power steering in your car. Very necessary for big/fast aircraft, as the plane is heavy and the force of the air resisting the movement of those control surfaces is very high.

If the engines fail, you still need to be able to control the plane, so there is something called a ram air turbine[1] which can be deployed out of the side of the aircraft. It is basically just a little propeller which spins in the breeze, which powers a pump, which supplies the hydraulic pressure to control the plane. So if the power goes out, you can still deploy that thing and have "power" assistance in controlling the plane.

The article says the ram air turbine did not deploy, possibly because the g-forces were holding it in, or perhaps because the g-forces or aerodynamic stresses were flexing the body of the plane so much that the turbine was held in place by the bending. So the pilots did not have "power steering" on the plane, and had to pull on the controls with "raw muscle force".

There is probably some mechanical advantage, probably both from the leverage afforded by the mechanics of actuation, and from the aerodynamics of the wing, that allow a single human to move the whole plane around. But it would still be very, very hard to control the plane without power assist, especially under such extreme conditions.

(Any pilots/aerospace engineers feel free to chime in/correct mistakes here).

[1] https://en.wikipedia.org/wiki/Ram_air_turbine

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

#120

Post by _ph_ » Fri, Mar 17, 2017, 7:11 AM UTC

ghshephard wrote: post #96

M_Grey wrote: post #63

Earlier quoted context omitted.

When I was in single digits, my mother and I were coming home from an international flight and the plane was struck by lightning. We lost a bit of altitude (felt like a TON of altitude subjectively), and yeah... it was a damned good thing we'd all been told to keep those seatbelts on. It was literally the difference between seconds of terror, and someone being seriously injured.

Using that philosophy, then anyone riding a bicycle, even if they aren't going at high-speed on road, should wear a helmet "just in case" there is an accident to protect their skull? There is a balance between annoyance and utility. I personally have no problem wearing a belt for the entire flight, including while sleeping. But I'm not to dismayed by those who leave it off, walk around the cabin, go hang out near the…

I think the bicycle helmet comparison is valid here - one big point is, that the typical bicycle helmets are not protecting your head well, you would need a motorcycle helmet for good protection.

I don't think one needs to be confined to the seat for the whole flight duration, but when sitting down, there is no good reason not to wear a belt either.