Comment by goku12 | Hacker News Reader

Comment by goku12 | Hacker News Reader

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> 1. The civilian planes fly on pre published routes and communicate with air traffic controllers in plain text

That's called a flight plan. It's just a declaration of intent, so that the ATCs know that you're expected. There are many valid reasons for deviating from the flight plan. For example, technical difficulties, bad weather, last minute diversions etc. That makes it very unreliable to predict the aircraft's location. You have to rely on your radar instead. The Military has some of the best radars around - especially on AEW&CS aircrafts and ships that stay close to conflict zones at all times.

> 1. I understand that there may be reasons why military planes might want to fly undetected but given they know where the civilian planes are and where they are flying, it should be trivial for the military ships and planes to avoid those areas.

Did you know that the Ronald Reagan Intl airport (DCA) saw one 'close call' between a civilian airliner and a military helicopter every month for the 13 year period from 2011 to 2024? [1]. That's close to 150 near disasters in total, for consecutive months for more than a decade! This is ridiculous!

Clearly, it's not a question if they can stay clear to avoid an incident. It's a question of if anyone cares at all.

[1] https://www.npr.org/2025/03/11/nx-s1-5324543/ntsb-dca-mid-ai...

If they deviate from their flight plan, don't they have to at least inform ATC to basically update the flight plan? I vaguely recall this from my PPL training about 20 years ago (I haven't been current for a long time) but I also never had to fly over international waters where I'd imagine you can't radio anyone so I don't know that that works.

> If they deviate from their flight plan, don't they have to at least inform ATC to basically update the flight plan

When on an IFR flight plan - at least domestically, especially in busy airspaces, the flight plan is mainly sort of a backup in case of lost-comms. You are typically vectored by ATC and your route may or may not be exactly what you filed. For example, in the SoCal area, the "standard" IFR routes can be pretty roundabout going around the approach/departure corridors of the main airports. But, if at any time the area is clear, ATC would typically clear you through a shorter routing.

I am not sure how it works for international routes. I know that for trans-oceanic routing, they typically make position reports over HF radio when over the ocean where there is no ADSB coverage.

The pilots have ipads and internet connections... can't they just have it check e.g. flightaware or similar tool for nearby aircraft and keep them alerted if something is getting too close?

Yes, that's called ADS-B. It's a huge improvement in avoiding collisions. But both planes need to be transmitting their location and vectors.

The military plane was running silent.

Why would both planes have to be transmitting? The military plane can read the commercial plane's transponder.

You are assuming military pilots will pay attention enough to unilaterally notice and stay clear without making mistakes. In the Dulles disaster at least, this clearly didn't happen.

With transponders on, both aircraft (via TCAS) and the air traffic controllers are able to pay attention and avoid the situation, so much better chance of catching.

Presumably military aircraft have their own ATC?

This does seem insane from a civilian perspective, but I'm curious to know the military side of it. Is this totally normal and not something they worry about, or is this as crazy as it seems for everyone involved?

From what I have seen, I believe that both types of aircrafts are controlled by the same ATC. Otherwise, the two ATCs will have to coordinate among themselves to create non intersecting vectors for each aircraft - which sounds needlessly tedious. But the military does have its own ATCs in many areas. They usually separate the airspace into 'civilian corridors' and 'military corridors', each under the control of the respective ATCs. In conflict zones though, the military operates entirely under their own control. The concept of ATC becomes a bit blurred here. The aircrafts are vectored either by ship-based controllers or more frequently by AEW&CS aircrafts. This is what I assume was happening with the tanker in the story. They were near Venezuela and the Curacao ATC had no information about the tanker.

Even if the military aircraft could read the ADS-B from the commercial plane, they were flying with their night vision goggles on. It's very unlikely that they would have seen all the instruments and could very well have missed the display. And since the two aircrafts were flying approximately at right angles to each other, the warning may have been degraded. (I'm not very sure about this point though. Needs confirmation.)

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