Remix.run Logo
adolph 5 hours ago

It is surprising to me that airports do not use an interlock system for deconflicting the various paths segments that may be occupied by a vehicle. Trains have used mechanical ones since the 1800s [0]. The story and comments seem to indicate the only thing preventing collisions is the mind of one person--that sounds insane.

0. https://en.wikipedia.org/wiki/Interlocking

0xffff2 5 hours ago | parent | next [-]

While it's not as sophisticated, there is a technology called Runway Entrance Lights [0] that does somewhat the same thing in the specific context of this incident. LGA is one of 20 airports around the country where this system is installed, and you can clearly see that the system was functioning if you know where to look in the surveillance video that is circulating online. For whatever reason, the truck did not respect the indicator that they should not enter the runway. So in this specific incident, short of rail-like physical limitations on movement, I think it's unlikely that any amount of additional technology would have helped.

0: https://www.faa.gov/air_traffic/technology/rwsl

sentientslug 4 hours ago | parent [-]

A runway light does not physically prevent a vehicle from entering a restricted area in the same way that an interlock would. Not saying it’s practical but an interlock would have indeed prevented an accident of this type.

0xffff2 4 hours ago | parent [-]

Yes, I get that. But an airport is not a rail network. The question is how you would actually implement physical interlocks on an airport in a way that works and is safe while controlling movement of everything from a pickup truck to an A380? It's an incredibly hard problem to solve. And keeping in mind too that the Runway Status/Entrance Lights first started development over 30 years ago and are still only deployed at 20 airports, despite being a vastly simpler system than one controlling physical barriers.

BobaFloutist 3 hours ago | parent [-]

I'm curious how much of a buffer there is between the time the sensors detect the airplane and it being safe to enter the runway.

Is it definitely safe to cross the runway in a vehicle moving a normal speed up to the moment before the lights turn red? Is it safe for a little bit afterward? Or is it unsafe even a little before the lights turn red?

lvspiff 4 hours ago | parent | prev [-]

If school busses can look both ways before crossing train tracks you'd think a firetruck would look both ways for airplanes coming down a runway. Don't want to blame the firemen though - this was a series of extrmeemly unfortuante scenarios and people trying to keep the airport running safely. For years people have been on soap boxes saying the FAA/NTSB needs to do better, and yet year after year they are poorly run and poorly funded.

dgoldstein0 4 hours ago | parent [-]

A quick Google gives me that a 737 typically lands between 144 and 180 mph. I think that's quite a lot faster than most people are watching out for. Good news is they are bigger than cars and so easier to spot at a distance but I'm still skeptical that "look before you cross the runway" is sufficiently safe. Keep in mind that the planes may not even be on the ground yet - at the top end in 30s they could go from a 1.5 miles away in the sky (and up to 300-400ft in the air) to plowing through your position (iirc runways are about 2 miles long for jets).

I wonder if it'd even be reliable to see such a plane coming fast enough.

Now multiply that by the dozens of planes in your vicinity, and by the 100ish big US airports.

filleduchaos 3 hours ago | parent [-]

> I think that's quite a lot faster than most people are watching out for

That isn't even beyond the top speed of a car, which non-trained humans are very well capable of tracking by sight - to talk of airport workers that are specifically trained to look for air traffic. It really is not that hard to tell that an aircraft is on short final if you are actually looking at it.

With four miles of visibility in light rain at night, the aircraft should have been perfectly visible (in a vacuum); what remains to be determined is why the ARFF crew did not see it. The answer to that could range from "they didn't look at all" to "the orientation of the runway relative to the surrounding neighbourhoods meant that the CRJ's lights got lost in the city lights".