Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Friday night’s near-disaster at JFK airport

viewfromthewing.com

Post reply on HN
Print view View original

261–270 of 372 posts

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

#261

Post by kylehotchkiss »

refurb wrote: post #216
kylehotchkiss wrote: post #118

I flew into JFK in December and was surprised the number of concurrent operations going on… landing queues of 5+ planes in the sky for the two runways, long takeoff queues, so many land operations… once you touch down it sure feels like the pilot knows they have to get that plane off the runway ASAP. Felt much more busy than I have previously going through LAX/SFO/London/Dubai. I wonder if the level of traffic at JFK…

Newark is super congested too. I remember flying from Michigan to Newark once and the ticket said “2 hours 45min” and I thought that was nuts, it’s like an hour flight. Turns out they tack on an hour leaving and coming for taxing and waiting in line. At least that’s how it was a decade ago.

At least they have the space to try to improve it, new terminal actually looks world class https://thepointsguy.com/news/newark-airport-terminal-a/

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

#262

Post by t0mas88 »

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?

The V1 decision speed is not fixed, it's calculated for each take-off based on weight, wind, runway conditions, maximum thrust settings etc.

It meets these constraints:

1. Low enough such that if you try to stop from that speed you will stop before the end of the runway

2. High enough such that if you have an engine failure at that speed, you will make it airborne on the other engine before the end of the runway

3. Not higher than rotation speed (you can't decide to abort after pitching the nose up and getting the aircraft airborne)

4. Not lower then minimum control speed (you can't keep directional control in case of an engine failure below minimum control speed, so your only option is to abort)

If there is no speed that meets all conditions, then your runway is too short and you can't go. Reducing weight helps, since you'll accelerate faster, stop easier, and take-off at a lower speed. So that's usually the solution if your runway isn't long enough.

Constraint 1 is why you're committed to takeoff above V1. If you would try to stop above V1 there is no guarantee that you'll stop before the end of the runway. While you are guaranteed to be able to take-off above that speed, even after an engine failure. So you take the problem into the air, run checks, and return.

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

#263

Post by t0mas88 »

quickthrower2 wrote: post #226
sklargh wrote: post #105

Earlier quoted context omitted.

Rejected takeoffs and clear air turbulence are why I never do infant-in-arms.

What is the alternative? Is there an equivalent of a infant car seat for the plane?

In Europe the standard is infant with extra belt. It attaches to the parents belt. Some US based airlines offer this as well, but it's not mandatory by the FAA.

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

#264

Post by t0mas88 »

WalterBright wrote: post #228
WalterBright wrote: post #227

Maybe 25 years ago, I'm not sure, there was some collision at an airport and the investigators were all wondering what happened, and were trying to reconstruct which airplane was where. It turns out that there were no video cameras monitoring the taxiways and runways. I asked why not? "Too expensive" WAAT? Even a 7-11 had an always on camera. "Too expensive. How would you get it to withstand the weather? How would yo…

These days you could point a handful of cameras at the taxiways, hook it to a computer, and have a realtime display of everything on the taxiways and runways. Then, the computer could detect potential collisions and alert.

You don't need cameras for that, they wouldn't work in lower visibility. Typically ground radar is used for this at large airports.

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

#265

Post by boredhedgehog »

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…

I believe that the causes for errors in perception and communication can be rather subtle, and therefore successful mitigations can be as well.

If the root error of the pilot here happened not at the runway crossing, but earlier, when confusing the K and J taxiways, then that's the location where possible preventative solutions should be considered.

Because once a pilot has subconsciously convinced herself that she's at another runway, it becomes increasingly impossible to override that mental block, no matter how many lights and sirens you use.

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

#266

Post by t0mas88 »

teaearlgraycold wrote: post #170
LarryMullins wrote: post #86

> (“Shit! Delta 1943 cancel takeoff clearance!”) This isn't a real quote, is it? I was surprised to read ATC losing their composure like that, but in the linked video/audio there is no utterance of Shit! that I can hear.

Honestly the "Shit!" is good communication. Breaking composure and normalcy can ensure everyone hearing the message treats it as urgent. That might make the difference when seconds are on the line.

The US is more loose on ATC phraseology than the rest of the world. The "shit" was probably the startle effect, but "cancel takeoff clearance" is the wrong call for the situation.

Standard when the aircraft is already moving: "Delta 1943 stop immediately, Delta 1943 stop immediately".

The "cancel takeoff clearance" call is supposed to be only used when the aircraft has not moved yet. Like: "Delta 1943, hold position, cancel takeoff clearance, due to xxxx"

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

#267

Post by tourist2d »

thaw239847 wrote: post #207
user3939382 wrote: post #200

I had a sort-of hobby of learning and listening to ATC at one point. Some of these guys were scary-unintelligible . I remember this Chinese ATC at some major airport saying as fast as he possibly could “clah de leh” which was supposed to be “Clear to land”. It’s amazing the system works as well as it does.

Having accent is not the same as being "unintelligible". Do you know how to say "Clear to land" in Chinese?

Unintelligible: impossible to understand.

Maybe you should brush up on your own English skills?

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

#268

Post by t0mas88 »

mkl95 wrote: post #215

Layman question here, why can't airplane collisions be predicted automatically? Something like an axis aligned bounding box around each airplane and some basic velocity equations. You don't want airplanes to be too close so an approximation should suffice.

A system for this exists, but it's new and not on many airports yet: https://www.faa.gov/air_traffic/technology/rwsl/pet/

It basically uses radar data to figure out whether it's safe to enter and safe to take-off on a runway. If it's not it will show red lights at the take-off position and entry points, pilots are trained not to cross those lights when red even if ATC says to do so.

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

#269

Post by cjrp »

jupp0r wrote: post #136
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…

I'm not disputing that it's very expensive but I find it funny that the "install red lights" solution is considered to be vey expensive.

It’s aviation; everything is 10x the cost due to (mostly sensible) certification requirements.

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

#270

Post by Doxin »

paganel wrote: post #255
Waterluvian wrote: post #75

Earlier quoted context omitted.

Fasten those seatbelts! Something I realized growing up, and perhaps this is a bias for others too: I always perceived of airline accidents as being crashes where everyone dies. Hence all the conspiracy silliness of “they just want to know what seat you were in to identify the body.” But my goodness there’s so many ways to be badly hurt without a big crash. In a way this feels akin to the highway bias: highways are f…

> But my goodness there’s so many ways to be badly hurt without a big crash. I remember an incident involving a private jet about a decade ago. The jet was at cruising altitude when suddenly it hit an air pocket and precipitously lost altitude. This being a private jet the occupants (some Greek businessmen) were drinking champagne or whatever, fact is they weren't wearing their seatbelts. A few of them died right on…

IIRC there's more than one incident report that'll mention something like "40 dents in the ceiling" from where all the unseatbelted folks got launched.

If you're seated in an airplane please make sure you've got your seatbelt on. You can have it a bit loose and it'll still protect you from this sort of nonsense much better than no seatbelt at all.

Post reply on HN