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‘Confirming we are cleared to land?’ Who said what at Austin

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Re: ‘Confirming we are cleared to land?’ Who said what at Austin

#211

Post by qikInNdOutReply »

hef19898 wrote: post #172
qikInNdOutReply wrote: post #166

Earlier quoted context omitted.

Is this sarcasm? In a thread were we discuss the breaking down of a systems run by professionals?

No, I'm dead serious. To usr another example: surgery. Just assume people cutting you up know what they are doing, even if you do not have the slightst clue.

Eh, i know surgery videos of people who know what they are doing.. so i can verify what they do in best/good times. (Recommend ARD/Alpha for those heart transplant videos) The daylight of observation keeps all involved honest.

Then i also know horror stories from someone thrustworthy, about surgeons throwing extracted body parts after nurses in high stress situations. No, i will not name names, but life and death situations need a perfect team and you dont always got that perfect team.

And surgery quality being dependant on the actual execution of the surgery (chief surgeon is not automatic the best individual contributor to surgery).

You want the most hours on the knife guy for best outcome, not some administrator with white coat.

Also you want to be near univesity clinics, they are spearheading new stuff, the more you get away from them, the operation technique is depending on the age of the doctors education and the hospitals financials to keep up to date, send doctors to regular re-trainings and try new things. Then there are lawsuits, they keep the people responsible, but also risk averse.

So if you are in a high risk situation, in a lawsuit rich country you are fucked, cause nobody will try the dice throw when worst comes to worst.

Trust in systems working, is upkept by untrusting agents.

So like in capitalism, were the price aware negotiate the deals down for the crowd who does not want to haggle.

Finally: The infrastructure & hierarchy of hospitals (in europe), as we know them today, emerged largely from the two world wars were lots of nurses and doctors were integrated into army structures. Which means it suffers from the same inefficency and structural problems those armies back then suffered from. Now you have the MBA process micro optimization on top of that, so i wouldnt trust that machine blindly..

Re: ‘Confirming we are cleared to land?’ Who said what at Austin

#212

Post by [deleted] »

0xFF0123 wrote: post #199
mulmen wrote: post #187

Earlier quoted context omitted.

Europe uses pessimistic runway locks but the US prefers optimistic locks. This improves throughput at US airports with the risk of a rollback on a dirty runway.

I'd be curious to know how much it actually improves throughput. It seems strange to use optimistic locks in such a safety critical process, when a more fail-safe approach is available.

[deleted]

Re: ‘Confirming we are cleared to land?’ Who said what at Austin

#213

Post by blitzar »

helsinkiandrew wrote: post #209
mulmen wrote: post #187

Earlier quoted context omitted.

Europe uses pessimistic runway locks but the US prefers optimistic locks. This improves throughput at US airports with the risk of a rollback on a dirty runway.

I'm not sure why this is a problem with airports with two runways (doesn't Austin have two?). I've been in a helicopter hovering over Heathrow airport where you can see the lights from the line of planes coming in to land every 45 seconds that looks like it goes off to infinity. Whatever technique they use there seems to work.

I assume it leads to a longer "cleared approach" phase and a shorter "cleared to land" phase and as a courtesy to the pilot behind, clearing the runway as quick as possible.

Taking a quick look at Heathrow approach, looks like runway is clear of the first plane landing when the following plane is 1-2 miles out and around 500ft.

Re: ‘Confirming we are cleared to land?’ Who said what at Austin

#214

Post by nmeofthestate »

hef19898 wrote: post #172
qikInNdOutReply wrote: post #166

Earlier quoted context omitted.

Is this sarcasm? In a thread were we discuss the breaking down of a systems run by professionals?

No, I'm dead serious. To usr another example: surgery. Just assume people cutting you up know what they are doing, even if you do not have the slightst clue.

https://www.theguardian.com/lifeandstyle/2022/sep/03/13-year...

"What follows is an account of how Martha was allowed to die, but also what happens when you have blind faith in doctors – and learn too late what you should have known to save your child’s life. What I learned, I now want everyone to know. In a small way, I hope Martha’s story might change how some people think about healthcare; it might even save a life."

Re: ‘Confirming we are cleared to land?’ Who said what at Austin

#215

Post by defrost »

thaumasiotes wrote: post #200
defrost wrote: post #154

Earlier quoted context omitted.

I suggest you take your objections up with the authors of, say, A Four-Dimensional Space-Time Automatic Obstacle Avoidance Trajectory Planning Method for Multi-UAV Cooperative Formation Flight or any number of other similar papers. Many prefer to think of an objects path as a trajectory in space-time (four dmensions) and for two ojects to "collide" their paths must coincide within that 4-D space within an Epsilon for…

But as ... you yourself ... note above, the planes aren't moving in four dimensions. If time is one of the dimensions, all the planes are doing is existing.

A plane (P1)'s past positions and projected future positions form a continuous path in R^4 (four dimensional euclidean space).

Another plane (P2)'s travel through various {X,Y,Z} positions at various times forms another path in R^4.

If those paths come close to each other then P1 and P2 are close in both space and time - ie. they are very close to a collision.

Collision detection and avoidance is problem laid out and (hopefully) solved in an R^4 euclidean space.

(at the very least - throw in some more independant variables that parameterise motion and you've got a higher order puzzle

Eg: Collision avoidance for two robot arms with 6 or 7 degrees of freedom each is a maze solving puzze in 12 or 14 dimensions).

Re: ‘Confirming we are cleared to land?’ Who said what at Austin

#216

Post by sokoloff »

jnsaff2 wrote: post #165

I got my PPL in EU and here it was drilled into me that in Europe there can be exactly ONE plane cleared to use a runway at any time. When the approaching plane is cleared then there is no allowance for anyone and anything to be on the runway. So if there is a departing plane waiting on the runway or someone crossing then the approaching plane is given "cleared approach runway 08" but never "cleared to land". Which a…

Not only can multiple planes be cleared to use a runway: one to depart, one to land in this example, cleared to land in a sequence, but also:

Multiple landing planes are allowed on the same runway surface at the same time in the daytime as in Oshkosh arrivals, but also a Category I (light single) can be cleared to land if the Category I or II aircraft to follow will be 3000 feet from the threshold, a Cat II (light twin) behind a I or II with 4500 feet of separation.

https://www.faa.gov/documentLibrary/media/Order/ATC.pdf

Re: ‘Confirming we are cleared to land?’ Who said what at Austin

#217

Post by cjrp »

jnsaff2 wrote: post #165

I got my PPL in EU and here it was drilled into me that in Europe there can be exactly ONE plane cleared to use a runway at any time. When the approaching plane is cleared then there is no allowance for anyone and anything to be on the runway. So if there is a departing plane waiting on the runway or someone crossing then the approaching plane is given "cleared approach runway 08" but never "cleared to land". Which a…

It seems that the US also has different rules about Low Visibility Procedures / protection of the ILS sensitive area; I don't believe you'd clear anyone for takeoff with someone on a 2-3 mile final, under LVPs.

Re: ‘Confirming we are cleared to land?’ Who said what at Austin

#218

Post by cjrp »

kelnos wrote: post #114
idlewords wrote: post #38

Earlier quoted context omitted.

The Southwest crew here is also to blame, they knew a plane was on short final to their runway in terrible visibility and for some reason took their sweet time taking off.

Or hell, they could have taken the even-safer option and informed ATC they were going to hold until FedEx landed. Regardless, I think it's too early to lay definitive blame until the NTSB report comes out.

Commercial pressures. Holding for Fedex would have added a few mins, maybe lost them their place in the queue, etc. It's not a reason to act unsafely, but it is a factor.

Re: ‘Confirming we are cleared to land?’ Who said what at Austin

#220

Post by sokoloff »

AdamN wrote: post #195
sitkack wrote: post #93

Earlier quoted context omitted.

> Have the courage to not take off. So many tragedies could have been averted if people just sat the fck down. If shit doesn't feel right, just chill until it does.

The corollary if you're already aloft is to "fly the damn plane". Everything else comes second.

“Never drop the plane to fly the radio.”
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