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Friday night’s near-disaster at JFK airport

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Re: Friday night’s near-disaster at JFK airport

#121

Post by Dalewyn »

fragmede wrote: post #117
Dalewyn wrote: post #60

Earlier quoted context omitted.

Manufacturing certifications, installation and maintenance inspections and certifications, auditing, etc. To put it into some relatable context, a simple electrical switch that you might grab for a few bucks at your local Home Depot would cost at least several hundreds of dollars because of all the red tape that must be satisfied for safety reasons. Safety isn't cheap.

Red tape isn't the phrase I'd use in this context since your point is that the switch will work 100% of the time even after being thru a literal hurricane, so the difference isn't merely the tape, but that there's been proper testing and engineering all the way down, which drives the cost way up.

I admit my vocabulary is failing me at the moment in finding similarly concise words to describe it, but I'm happy if the meaning gets through one way or another.

Re: Friday night’s near-disaster at JFK airport

#122

Post by doubleunplussed »

jamiek88 wrote: post #103
ajross wrote: post #91

Earlier quoted context omitted.

> For those thinking about preventative solutions, there are some existing, all very expensive of course. The simplest is placing a row of red lights in the ground at all intersections to runways. That's... a street light.[1] When street lights become "very expensive of course" it's time to revisit our priors about how we regulate. And I say this as someone not normally inclined to libertarian rhetoric. [1] To be cle…

It’s not a street light. You aren’t going to have poles or hanging lights on a runway. It is embedded lights. That have to work without fail in extreme temps, all weathers, with planes rolling over them all day. They have to have certain visibility at different angles, they have to fail gracefully. These things are rarely ‘that’s just…’

They're a backup system if the currently in-use systems fail. If they work only 99% of the time, they've cut accidents in the class they are designed to prevent by 99%. That's excellent. Perfection does not seem any more necessary here than in other contexts, and seems like the enemy of the good.

This compliant seems to me akin to me not backing up my computer's internal drive to this external drive I have sitting on my desk, until I can make a little RAIDed setup to address the small probability that the backup drive will fail. Having no backup at all is worse than requiring a high standard to the point that the backup may not be implemented.

It's not like if they break, nobody will notice. Install them, have a process to verify they're working regularly, fix them if they break. Any downtime whilst they're being fixed is just as risky as every day the project is delayed to to this high standard of reliability.

Re: Friday night’s near-disaster at JFK airport

#123

Post by nkozyra »

tempestn wrote: post #108
BoorishBears wrote: post #95

Earlier quoted context omitted.

That's an example of why they're expensive: they need to be engineered as if one day they might be. And no one chooses when or where that is

That doesn't seem logical if the alternative is not having the lights at all.

An unreliable system is often worse than a non-existent one.

Re: Friday night’s near-disaster at JFK airport

#124

Post by remh »

michaericalribo wrote: post #120
mgsouth wrote: post #115

Earlier quoted context omitted.

Wow. That's almost unheard of. There's a speed called "V1"; this is the last possible moment for a pilot to start aborting the takeoff. There's another speed called "Vr", which is when the pilot starts the rotation (lifting the nose off the ground) [1]. Vr is higher than V1. Past V1 its unsafe to abort, even if a tire blows or an engine fails. The only time it would be aborted would be if the pilot thinks the plane i…

Whoa fascinating. What makes it necessary to commit after V1?

As per the linked website: " If the airplane reaches a peak speed of only 10 knots beyond V 1, the brakes must now dissipate 20 percent more energy than had the abort been initiated at V 1. Beyond the fact that there is no certification requirement for the brakes to be able to absorb any energy beyond that existing at the highest weight and V 1 combination demonstrated, there also is no performance data to know how much runway would be needed even if the brakes are able to handle the extra energy. Adding to the chaos, one brake must now absorb all the energy of the aircraft, as the blown tire’s brake has been rendered useless."

Basically you'd be unlikely to get the airplane to stop before the end of the runway because brakes are not designed to handle breaking at such speed (keep in mind that an airplane lands at a slower speed than it takes off thanks to the flaps).

Re: Friday night’s near-disaster at JFK airport

#125

Post by coldcode »

christophilus wrote: post #48

The animation in the tweet at the end of the article is something. Based on that, the deceleration looked remarkably fast. I imagine that was quite the ride for the folks in the Delta jet.

I experienced a takeoff abort in New Orleans in a 737 when some birds (I think that's what the pilot said afterwards) clogged up the pitot tubes (in the 1980s) and either the plane aborted the takeoff or the pilot did. It was a max effort whatever it was, scared the shit out of everyone.

Re: Friday night’s near-disaster at JFK airport

#126

Post by jMyles »

I want to offer a bit of a different perspective than the one I'm seeing in other comments which (totally reasonably) wonder if a) JFK is too busy or needs some safety upgrades and b) whether voice contact with ATC is the best way to reduce risk during unusual events like incursions.

I'm just an amateur enthusiast who listens to a lot of ATC, so take this assessment with that grain of salt:

JFK has long had a unique subculture with respect to ATC (embodied most famously by the flourish and wit of Kennedy Steve, but often apparent from the entire ATC corps on both ground and tower during busy times), and strange as it sounds, it might be a part of what averted this disaster. At other airports, it seems to me that it's totally possible that this goes far worse.

The controller did a few things that are unusual in ATC, but not totally unheard of at JFK in particular:

* Completely changed tone of voice. He yelled into the mic. That doesn't happen often in ATC.

* Yelled "SHIT!" to open his transmission.

* Spoke in a way that emphasized speed and urgency even if it cost a little clarity (eg, some news outlets have transcribed "cancel takeoff clearance" as "cancel takeoff plans" because of how intense and fast the controller is yelling)

Assuming the aircraft were on a collision course (something we'll probably know for sure only when the FAA report comes out), this was less than 1.5 seconds (perhaps less than 1 second) from an impact.

A different transmission, like you might hear at say LHR or LAX, where the controller keeps a monotone and simply says, "Delta 1943 cancel takeoff clearance" might not have gotten the attention so quickly and helped the Delta pilot initiate the reject so rapidly.

I think that this incident is an example of a) how JFK's unique ATC swagger may not be just for show, but may actually be a part of the safety culture of that airport, and b) how effective voice contact with ATC is at achieving rapid response from pilots.

Ideally, this investigation prompts some study into what might seem like a silly topic: whether the "New York attitude" of JFK controllers has a positive safety impact that isn't felt elsewhere.

Re: Friday night’s near-disaster at JFK airport

#127

Post by giantg2 »

hn_user2 wrote: post #43

For those thinking about preventative solutions, there are some existing, all very expensive of course. The simplest is placing a row of red lights in the ground at all intersections to runways. When an airplane is cleared for takeoff and until it is airborne the controller presses a button and turns all these lights red. Pilots are instructed that regardless of clearance, a red light over-rides that, and to never cr…

These sound more like detecting something. How about preventing miscommunication? They weren't even on the correct runway.

Re: Friday night’s near-disaster at JFK airport

#128

Post by CamperBob2 »

Spooky23 wrote: post #101
ars wrote: post #79

Earlier quoted context omitted.

The extra cost for safety is reducing safety because it's causing this not to get installed. Maybe it's worth having a worse system that actually is there.

Easy to preach, harder to practice. When I was an intern I got to help change the blinking red light on top of a 50 story building. It’s a big deal that was scheduled weeks in advance and probably involved two dozen people, a special lightbulb and a bunch of coordination. Even among the team working it plenty of “how many X does it take to change a light bulb” jokes were told. But consider than a pilot depends on cer…

What would be better for safety? One $10000 light bulb, or ten $10 light bulbs?

Re: Friday night’s near-disaster at JFK airport

#129

Post by techdragon »

seo-speedwagon wrote: post #111
Symbiote wrote: post #67

Earlier quoted context omitted.

I've experienced maximum breaking in an emergency landing. Many passengers (including me) instinctively put their hands on the seat in front to steady themselves. You could easily slide around if the seat belt were loose. It was it worst for children whose legs didn't reach the floor, but there were none seated near me.

A long time ago I was on a FAA certification test flight where we tested maximum braking. I wasn’t in the flight deck, so I don’t know if it was literally true, but it was described as “pilot standing on the brakes” and it sure felt that way. All our equipment was strapped down and when the pilot hit the brakes for our first test my glasses flew off my face. Those brakes are no joke

Maximum breaking, is powerful stuff… Real red hot metal and tolerances engineering stuff. You have to be able to stop the airplane at it’s maximum take off weight at the maximum takeoff ground speed (got to account for tail winds) within the acceptable safety stopping distance on the runway, and they have to sit there after this without any help for several minutes to represent the time it can take to scramble ground safety and rescue crews to assist... On big jets this involves sacrificing the breaks and often even the tires, as the breaks get glowing red hot and the heat radiating off them will be strong enough to heat up the air in the planes tires to the point that safety systems like fusible plugs/patches designed to melt (but not break from normal pressure) kick in and the tires blow out the plugs and deflate due to the exposure to sheer heat coming off the breaks as they sit there for a few minutes soaking in the heat from the red hot breaks…

Good video of the test conditions for a 747-8 here https://youtube.com/watch?v=qc_v6tXsv6g

Re: Friday night’s near-disaster at JFK airport

#130

Post by cmurf »

tobinfricke wrote: post #10
tobinfricke wrote: post #9

Earlier quoted context omitted.

Re #2: We already have something like this at some airports. I wonder whether it was available on the runway/taxiway in question? https://en.wikipedia.org/wiki/Runway_status_lights

Seems like the particular intersection where this incident occured is supposed to be protected by RSL: https://www.faa.gov/air_traffic/technology/rwsl/media/JFK.pd...

Runway Entrance Lights at intersection J/4L which is where the incursion happened. These are taxiway centerline lights, and should have been red at the time. Here's the gotcha: REL only illuminate once the departing aircraft reaches 30 kts. https://www.faa.gov/air_traffic/technology/rwsl/pet/

Based on the animation https://twitter.com/CaseWade/status/1614342894248394752 at 00:14, I'm pretty sure AA 106 was no longer in visual contact with REL lighting by the time DL 1943 reached 30 kts.

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