[nine_k]

The incursion was by a fire engine which was hurrying to handle yet another incident. The weather was foggy, it was raining, and the incoming plane was already low, so it was pretty hard to tell it apart from many other lights shining from the fog in the distance. It's not easy to assess the speed of motion when a fuzzy ball of light is advancing right towards you.

The pilot was given the clearance to land before the fire engine was dispatched. Apparently there was not even enough time for the crew to max out the thrust and try to lift off the strip even if they managed to notice the lights of the incoming fire engine.

[aeternum]

Planes use a system called TCAS to prevent collisions in the sky, this system is independent of ATC and works even if ATC is not paying attention or if pilots have the wrong frequency tuned. It detects impending collisions and gives both pilots clear and automated alerts plus an action IE climb + turn to execute immediately to prevent a collision.

A similar system can and should be used for runways.

As a thought experiment, imagine how many car accidents there would be if instead of traffic lights, each person had a AM radio in their car and police officers called out over the radio which cars should proceed across the intersection. That is the unfortunate state of modern? aviation.

[ceejayoz]

TCAS disables below 1,000 feet because there’s too much stuff at an airport.

[oceanplexian]

I have ADS-B in my airplane and can see everything on the ground on a pretty map as if it were literally a video game. I can see landing aircraft in realtime while holding short or crossing a runway. The emergency responder should have had it in their fire truck.

The technology already exists. The problem has already been solved with an iPad and a $200 receiver. Almost certainly some BS regulation or rule was at least partially responsible here.

[ceejayoz]

Information overload is a thing, and there are a lot of ground vehicles at a place like LGA.

[fc417fc802]

Consider that if you have access to all the local ADS-B data you can project paths forward through 3D space for the next, say, 30 seconds or so. Using GPS you can determine your own position in 3D space. At that point it's trivial (and I'm not handwaving here, it is literally extremely trivial) to filter projected paths based on passing close enough to your own in 3D space (ie accounting for altitude). Stick that on a tablet and require it to be present in all vehicles that operate on the tarmac.

It wouldn't need to work 100% of the time because you'd still be required to contact ATC. The only requirement is that it have a reasonably high chance of alerting drivers to potential mistakes before they happen.

Which is to say this incident was trivially preventable had anyone with authority over these sorts of things cared to bother.

[ceejayoz]

> for the next, say, 30 seconds or so

But this is a hand-wave.

This is a situation where both vehicles got explicit permission from someone who's supposed to know what they're doing. These sorts of runway crossings aren't unusual - and this one was responding to an emergency - and at a place like LGA there's always gonna be a plane on approach.

The difference between "hold short at runway 22" and being on runway 22 is much less than 30 seconds in some cases.

[aeternum]

Well imagine if we designed a TCAS-like system that did work below 1,000 feet!

[ceejayoz]

TCAS is mostly "how close to another plane am I?"

In flight, the answer really shouldn't ever be "less than 500 feet". During landing, the answer almost certainly will be "less than 500 feet"; a plane's queued up to enter the runway after you land, a ground vehicle is working on something near but not on the end of the runway, etc.

It's a surprisingly tough challenge to solve a) reliably and b) in a way that doesn't cause a whole bunch of false go-arounds wreaking havoc on the busy airport.

[aeternum]

It's a much easier challenge when every moving vehicle in the airport environment is issued a relatively exact clearance.

The ATC clearance gives each vehicle a movement contract.

It would be great if avionics actually took those into account. Avionics should help pilots ensure their vehicles don't break the contract and should also alert immediately if other vehicles have, or their velocity vector is such that they will violate the contract. IE braking rate is insufficient to stop before the hold short line. ATC computers should ensure no conflicting clearances are issued.

None of that happens right now.

[FireBeyond]

Apropos of anything else, if you are operating an emergency vehicle on the road in "emergency mode", liability defaults to you unless demonstrably otherwise. I get that this is not a road, but...

Almost every fire department in the country has SOPs for operating in emergency mode that generally include coming to a stop at all intersections or at least being able to affirmatively clear the intersection.

This personal liability is not particularly appealing in the world of fire, where ~70% of US firefighters are volunteer (not that the story is better in career), so codifying it in SOP allows departments/governments to negotiate insurance policies for their members, saying that "if you were driving in emergency mode, but within SOP, the department's insurance will cover your personal liability".

I saw the video. The incoming engine didn't appear to slow until too late, either.