[sib301]

I just listened to the ATC recording from immediately before the collision. ATC instructs the helicopter to pass behind the CRJ. I’m fairly certain a few minutes before that, ATC instructed the helicopter to maintain visual separation, which is common. They typically ask, “do you have the aircraft in sight” and if you respond in the affirmative they rely on you to maintain safe distance.

I should mention that in the recording you can only hear one side of the conversation, so I don’t know whether or not the helicopter said whether or not they had visual contact with the plane they collided with.

Either way it doesn’t seem to be the fault of ATC. Of course we’ll know more as additional information becomes available.

[blantonl]

Here is the ATC audio between the Tower and PAT-25. Helos that transition DCA's airspace use a separate VHF frequency from traffic landing and departing, but talk to the same tower controller.

https://archives.broadcastify.com/44114/20250129/20250129200...

* At 5:41 - 5342 is given instructions for circling to 33.

* At 6:45 - PAT-25 reports Memorial

* At 7:06 - tower gives PAT-25 traffic advisory about 5342 and PAT-25 reports traffic in sight and requests visual separation

* At 8:12 - tower asks PAT-25 if they have the CRJ in sight and tells him to pass behind the CRJ. PAT-25 again reports traffic in sight and again requests visual separation.

* At 8:28 - crash occurs, exclamations, go arounds issued

[fblp]

This is wild to listen to. A) this is a busy atc channel and it's amazing how much complexity is coordinated over noisy radio. B) within minutes of the accident happening (at 11:48) the ATC controller is calmly asking helicopters in the air if they can assist in search rescue operations asking, if they have search lights and direction them. This is whilst diverting and grounding flights.

[consp]

> over noisy radio

I've been told the noise on the recordings is always a lot worse than in practice due to the location of the recording antenna not being ideal. I have no idea if this is correct or not. Maybe someone can enlighten this.

[FL410]

Yep. Radios are much clearer in the air. VHF is mostly line of sight and planes have the benefit of altitude. Approach/center comms can get a bit scratchy at times mostly due to distance, but approach/tower is almost always perfectly clear.

[thowawatp302]

Yes, having tried to listen to ATC with an SDR— the public recordings are made from antenna that placed near the airport, while the official recordings are made from the feeds that the ATC is listening to— and those antenna have their lobes pointed toward the sky.

[jillesvangurp]

I watch a lot of pilots on Youtube. Most of them use some kind of audio splitter to record sound. You hear what the pilot hears. But minus the plane noise, vibrations, etc (unless that's mixed in via some open microphone). So, it's actually better.

So, it really is that bad. Especially when flying low, on the edge of the range of the radios, etc. VHF radio is ancient technology. It's not great even under ideal conditions.

If your phone calls sounded that bad, you'd want to upgrade your phone or switch operator. Really not acceptable for consumer grade communication. Not even close. This is how phones sounded half a century ago. "can you hear me .... are you there ..... can you talk louder ....". My grand mother never really unlearned 1930s phone etiquette. Phone calls with her were short (cause expensive) and she'd be shouting at you because that's what you did. Be brief, loud, hang up as soon as possible. That's what pilots still do. My grand mother was born during WW I (not II) and she's been dead for nearly 20 years.

The aviation world is very conservative with new/better/any technology. They stick with "what works". Even if arguably it barely works. Like pretty much the vast majority of radio exchanges between pilots and controllers over VHF radio. Learning how to talk on the radio is the second hardest part of getting an instrument rating. The only thing that's harder is flying a plane with zero visibility ... while suffering extreme information overload because of the constant radio chatter and dealing with confused/stressed/pissed off controllers who have to juggle you and 20 other planes.

A lot of radio exchanges are routine exchanges that involve very basic information: call signs, transponder codes, codes for approaches/departures, courses, altimeter settings, altitudes, weather information, etc. And then a lot of double checking the other side heard correctly, repeating back what you heard, etc. Radio communication compensates for the lack of a more robust/sane way of exchanging information. There literally is no way for a controller to send you information in written format. Other than using their private phones. So, it all gets spelled out over low quality VHF radio.

There's no good technical reason to not do something vastly more reliable, less intrusive, and less error prone. Some might say safer. Many planes have star link connections these days. The passengers get better connectivity than the pilot. They could be having video calls with the controller with crystal clear audio from anywhere on this planet instead of yelling to them over VHF only when they are in range. They could be sending each other emails, documents, digital maps, and lots of other machine readable information, etc. Not a thing.

It's more a challenge of agreeing on what such a vastly better thing would be and then updating each and every plane and tower, airport, controller world wide with equipment that supports that. Add design by committee to the mix and the "state of the art" is something that would make any competent engineer born after 1970 blush.

[singleshot_]

> This is how phones sounded half a century ago. "can you hear me .... are you there ..... can you talk louder ...."

No, landlines in 1975 sounded outstanding. I didn’t hear the phrase “can you hear me now” until I got my first oki (1992?)

[jillesvangurp]

Local ones yes. International connections were a lot less nice.

[FL410]

YouTube is not a good representation of what you hear in a headset. Half the time the mic taps aren't impedence matched and sound like shit.

Besides that, most "controlling" (i.e. instructions that require action) comms have a handshake of sorts - the pilot repeats back the instruction for the controller to confirm. They don't just bark out instructions and hope you heard it, they listen for you to read them back, and will keep doing so until successful. So, even in cases when the comms are degraded, you will go back and forth until there has been positive confirmation (readback) you heard the instruction correctly (or they'll just give you a new frequency).

[throw0101c]

> A lot of radio exchanges are routine exchanges that involve very basic information: call signs, transponder codes, codes for approaches/departures, courses, altimeter settings, altitudes, weather information, etc.

They are also in a fairly standardized format with reserved "keywords" for many important aspects of operation ("hold short", "line up and wait", "cleared to X"):

* https://skybrary.aero/sites/default/files/bookshelf/115.pdf

English is the lingua franca of ATC, but it is recognized it is obviously not everyone's first language.

[jcrawfordor]

Honestly a lot of those recordings probably do sound a lot worse than the radio audio. I rarely see YouTube recordings that are as audible as the radio is in person. Here's what seems to be the reason:

The common splitters you can buy to break out your headset connector to a recorder don't account for the signal level, which is very high on the headset connectors as aviation headsets are traditionally pretty high impedance. I've struggled with the headset audio blowing out even a fairly nice recorder (a Zoom) with the gain turned all the way down. Phones and pocket reporters don't even offer a gain adjustment and the recording can end up almost unusable. In a lot of YouTube videos of pilots, even most, it's pretty obvious that it's clipping at the recorder the whole time. Perhaps even worse, a lot of people are using like a GoPro with auto-gain, so you get the worst of both worlds: it ramps up gain until the noise is loud, and then when someone starts talking, it ramps down the gain, but a little too slowly, and it's still clipping even when it hits minimum.

It's not very common to have trouble understanding the controller when in the air. AM radio at line of sight (as is the case when you're flying) is pretty robust. Maybe the hardest thing to understand are helicopter pilots because there's often rotor noise on their end.

[omilu]

>>>They could be having video calls with the controller with crystal clear audio from anywhere on this planet instead of yelling to them over VHF only when they are in range.

Your forgetting about latency, which matters when you are trying to land an airplane. Also who cares if you could talk to the aircraft from anywhere in the world with different technology? The only thing that matters is there is a low latency audio connection between the traffic controller and all the planes coming in. Direct line of site VHF communications is better in every conceivable metric then any alternative. It has nothing to do with old technology or design by committee.

[V99]

Besides the "we already have it everywhere" bit, the big advantage of analog AM over UHF/VHF is that it degrades fairly gracefully. As you're getting too far away the signal gets harder to pick out from the noise, but it's not an all-or-nothing digital signal.

That doesn't matter much over Washington DC, but when you get out towards the western half of the country the transmitters are a lot more widely spread out. There's mountains in the way. There's limitations to how low you can be and still be reachable, which sometimes has to be balanced against how high a GA plane can comfortably fly, or oxygen requirements for the occupants.

A better sounding "modern" system is generally going to be worse at handling those marginal situations, which would probably require building a lot more radio outposts in fairly remote areas to compensate.

But the big problem with requiring anything new is getting it into the existing fleet of thousands of decades old certified aircraft. You need a new radio stack. You probably need new antennas. Changing anything on certified aircraft needs tons of paperwork and things like Supplemental Type Certificates for each individual model of aircraft that make it cost 5-50x what you'd think it should cost. Military aircraft are probably 10x worse beyond that.

A handheld COM radio is maybe $200 from Sporty's. Take basically the same thing but package it as a basic Garmin COM radio (GTR 205) and it's now $2,300. If you want a NAV radio in it too (GNC 215) now it's $5,400. Add GPS and ADSB-Out (GNX 375) and now you're at $9,000. You can buy an entire currently airworthy (really old) plane for maybe $30,000.

For some uses you don't even have to have any radio or transponder/ADSB installed on your aircraft. Some aircraft don't even have an electrical power system to run one. Granted they're not allowed in the middle of Washington DC, but still trying to require the entire fleet gets fancy new digital radios would be a monumental challenge and fantastically expensive.

There are some existing better ways to communicate. Larger planes usually have CPDLC (Controller Pilot Data Link Communications), which is basically text messaging from ATC to the plane avionics. That's how they receive their IFR clearance at major airports. In an airliner you're not generally reading it out over the radio and scribbling out your "CRAFT" acronym on a scratchpad like you see on YouTube. (Even your 4-seat steam gauge Cessna can do this via PDC (Pre-Departure Clearance) at supported airports with something like ForeFlight on an iPad).

CPDLC can also be used in the air to communicate less time-sensitive things like altitude changes and reroutes, talking to the operations department of the airline, etc. There's no reason you couldn't put this in smaller GA planes and towers, other than cost.

Airliners that do transatlantic and -pacific routes also have satellite communications instead of using old-school HF radios (which are even worse than VHF).

[watersb]

The ADS-B Transponder requirement for non-commercial aviation took decades.

And oh, how we howl at the expense! $2500 so your airplane pings out its position and heading.

I stopped flying right about then, mid-2000s, so I never had more than a hand-held GPS to go along with the usual radio stack.

https://en.m.wikipedia.org/wiki/Automatic_Dependent_Surveill...

[lawlessone]

I think the crash was at 8:22 or 8:21, you can hear sudden commotion at that time.

[wyldfire]

In the video from the webcam there's another plane which is much easier to see. Could they have asked about "the aircraft" and the helicopter pilot mistook which one they referred to? "yes I can see the plane flying much higher"

[unsnap_biceps]

It's possible but generally there's implied context to ATC. ATC would only instruct you to watch out for possible vector interceptions. flying over an approach path, the context would be that you would look for aircraft on approach, not ones in holding or other patterns above.

That said, it's possible they mistook which aircraft to look for, but it's unlikely imho and we will likely never know for sure, as I would presume the pilots are deceased.

[dylan604]

I got a lesson in how ATC works with helicopters up close and personal on a helicopter tour. ATC had the helo pilot hold position while an airplane was on final approach. I asked the pilot why we needed to hold as we could clearly see the aircraft and were to my lack of knowledge on the subject "plenty" far away. (It actually took me a second to locate the airplane as my sense of scale was not expecting the plane to be so small which is part of why I made the assumption we were plenty far away.) That's when the pilot told me we were not in the way of the approach but if the pilot had to declare a miss (or whatever they call it) and climb to circle around. The helo was near the path for the plane on the abort flight path. Once the plane was on the ground, ATC allowed us to continue.

It was my first experience in an aircraft seeing how ATC controlled the airspace directly. Lots of respect to the folks in ATC with a fraction of understanding in just how much they have to deal with other than the obvious take-off/landings.

[TylerE]

There was a second American Airlirns flight only a couple miles and a thousand feet higher in altitude in the same approach course. You can actually see it in the video that’s circulating.

[mlyle]

It's pretty dang easy to misjudge distances and closing rates in a plane or helicopter, especially at night.

[ketanmaheshwari]

Is this true for the trained pilots as well?

[paulddraper]

It's next to impossible to know at night.

The only thing you have visually is direction / angular velocity.

[pfdietz]

And if you're on a collision course the other vehicle will appear motionless, with no change in direction.

If the airliners was approaching faster than the helicopter it could have been approaching from behind. How large is the field of view of a UH-60?

[lightedman]

"How large is the field of view of a UH-60?"

Massive, you're practically against the glass. Visibility below is more obstructed than visibility above or to the sides.

[paulddraper]

From the radar tracking, they appear to have been at least somewhat head-on.

(Also at a low altitude in a large city ... lots of lights.)

[sklargh]

Yes.

[throwaheyy]

No, that aircraft (having taken off from Reagan, visible in the full not-cropped videos) is close to the Kennedy Center camera but is nowhere near where the CRJ and helicopter were.

[trhway]

> easier to see.

One has radars even on recreational boats. That was a military helicopter. At night. It would be hard to believe that it doesn't have nor radar nor IR cameras, and the plane would be lightened up like X-mas tree in both.

[jahewson]

Marine radar is trivial compared to air-to-air radar. The Black Hawk, like most aircraft, does not have an air-to-air radar. IR cameras would be completely inappropriate for the situation but night vision goggles are a possibility I guess - though still have all the same drawbacks as using your eyes - you have to look in the right direction and recognise what that small dot is that you’re seeing.

[trhway]

>Marine radar is trivial compared to air-to-air radar.

like in the case of a boat, the air-to-air radar is still peanuts compare to the cost of the plane/helicopter

>The Black Hawk, like most aircraft, does not have an air-to-air radar.

Pretty surprising for the military. You'd like to know when an enemy fighter or a missile coming for you. And military frequently operates in the territories without any ATC, so you'd like to see even the friendly planes and helicopters too. Say at night over Iraq.

And even without radar - simple ADS-B receiver attached to notebook plotting onto the screen of the notebook would be a great improvement in that situation over DC or anywhere over US.

> IR cameras would be completely inappropriate for the situation ...recognise what that small dot is that you’re seeing.

in visual at night you have a sea of city lights with some low flying lights you can easily mistake for ground lights. In IR all those city lights would pretty much disappear, while the plane's engines and exhaust would be a very bright light against very dark background of the sky.

[bigiain]

>>The Black Hawk, like most aircraft, does not have an air-to-air radar.

>Pretty surprising for the military. You'd like to know when an enemy fighter or a missile coming for you.

I'd guess the answer to "when is an enemy missile heading towards me" would usually be "shortly after you turn on your radar transmitter and reveal your location"...

[trhway]

>turn on your radar transmitter and reveal your location".

That was in the past. Even if you don't turn your radar on, in IR cameras widespread today your engines are visible from tens of kilometers, and without your radar on the missile comes to you without you being aware of it.

[nradov]

Lack of air search radar on military utility transport helicopters is only surprising to aggressively ignorant people who can't be bothered to do a few minutes of basic research. Even some tactical jets that operate over hostile territory lack air search radar, although they do have other defensive systems.

[dumah]

The air-to-air radar is not necessarily peanuts compared to the helicopter. A recent sale of blackhawks to Greece was priced at 1.95B for 35 helos. A past sale of 36 Apache Longbow radars and support to Korea was priced at 3.6B.

A helo is a sitting duck for a fighter so what would it do anyways. AEW will tell the helicopter about a fighter and vector them to safety. An active military radar will only be lit when necessary.

I do agree that an iPad with flight radar should have been able to help avoid this incident, much less the engineered solution that is warranted in a combat aircraft.

[t0mas88]

The common mistake with this is seeing a plane, reporting "traffic in sight" but looking at a different plane than the one the controller meant. Especially at night where distance is near impossible the estimate and you can't see differences in types of planes.

I have no extra information on this incident so this is only generic input.

[rsanek]

Do you want to post a link the recording?

[unsnap_biceps]

it's linked in https://news.ycombinator.com/item?id=42874330