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Comment by twoparachute45 | Hacker News Reader

It wasn't a police chopper, it was a military VH-60, also known as a "White Hawk" [1]. It's a VIP transport helicopter, the same type that is used to transport the president.

~The flight track of the helicopter [2] starts at a property in McLean, VA (edited to remove likely inaccurate info)~

The chopper was based out of Fort Belvoir, and based on similar past flight tracks, looks like it probably took off from there too. CNN is reporting that there were 3 soldiers onboard, and no VIPs.

1: https://simple.wikipedia.org/wiki/Sikorsky_VH-60N_White_Hawk

2: https://globe.adsbexchange.com/?icao=ae313d&lat=38.952&lon=-...

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> The flight track of the helicopter starts at a property in McLean, VA

that's almost certainly not where the flight started, due to intricacies of how this sort of flight tracking works.

if you look at [0] it has tracks of both flights. toggle the right-hand sidebar, if it's not open already, and you'll see a table containing both planes. the helicopter (PAT25) is yellow, the plane (JIA5342) is blue. the legend right below that explains the color-coding - the plane's data came from ADS-B, while the helicopter's data came from multilateration (MLAT).

MLAT [1, 2] works by having multiple ADS-B feeder stations cooperate in real-time and deduce an aircraft's position based on timestamps of when the signal is received. it allows tracking aircraft that only broadcast the more limited Mode S data, instead of the newer and more detailed ADS-B.

because it requires multiple cooperating receivers, the start of the track in suburban McLean does not mean it took off from there. it just means that was the point in its flight where it became visible to enough receivers that MLAT was able to pin down a position.

you can also see this difference just by looking at the tracks - the plane is broadcasting its own position continuously, so its track is nice and smooth. meanwhile the helicopter's flight looks "jagged" in a way that does not match what its actual flight path would have been. this is an artifact of the small errors introduced by MLAT.

0: https://globe.adsbexchange.com/?icao=ae313d,a97753

1: https://www.flightaware.com/adsb/mlat/

2: https://adsbx.discourse.group/t/multilateration-mlat-how-it-...

And just to be clear, the POTUS/super-special VIP transport is run by the USMC out of Quantico[1], a bit further to the south along the Potomac. Belvoir is US Army, and does have VIP heelicopters (obviously), but it's not the same group that lands at the White House.

1 - https://en.wikipedia.org/wiki/HMX-1 They have some Ospreys and other things as well, but HMX-1 is the most famous and recognizable.

[2] shows the helicopter taking off 2 miles away from the old saudi embassy in McLean marked “permanently closed” on google maps. (The current embassy is in DC proper, directly across the river from DCA airport)

I don’t think thats strong evidence that it took off from the old Saudi Embassy - thats pretty far away even given your caveat about accuracy.

Edit: it looks to me like the black hawk was coming from somewhere else with its ADS-B turned off entirely, and then turned on ADS-B once it reached the potomac to approach DCA. The first two datapoints of that flight already show it going 110mph, which its unlikely to be able to accelerate to in just 0.2miles after take off.

Edit 2: The route also looks very similar to this flight from 11 days earlier (but reversed in direction): https://www.flightaware.com/live/flight/PAT25 This shows the Blackhawk at 300 feet passing by DCA on what seems like a routine or training flight? I don't know how to look up historical flights to see if this is a commonly-flown route. On that flight, the Black Hawk flew past DCA at 300 feet of altitude, and the last FlightAware data for the American Eagle passenger flight showed 400 feet of altitude.

I didn't say it took off from the old embassy. The flight track starts at the backyard of a house that is currently owned by the embassy. You can see the owner of that property by searching that address here (the site doesn't support a direct link): https://icare.fairfaxcounty.gov/ffxcare/search/commonsearch....

Thank you!

Regarding your edit: that's a good point, but the vertical ascent rate of the chopper at those first few data points shows 400-800 feet per minute, which is consistent with a chopper taking off...'

edit: your second edit makes me think you're right though, tonight's flight track was pretty consistent with the past flight track where it looks like it both took off from and landed at Fort Belvoir.

That house doesn't seem to have enough clearance vs the trees to land a helo. Note that Langley (CIA) is nearby.

811 Lawton St, Mc Lean, VA 22101 Name: SAUDIA ARABIA ROYAL EMBASSY OF, Mailing Address: 8500 HILLTOP RD STE 301 C/O FINANCIAL DIRECTOR FAIRFAX VA 22031 4310

CNN is reporting the helicopter came from Fort Belvoir.

https://www.cnn.com/us/live-news/plane-crash-dca-potomac-was...

The helicopter seems like it is typically stationed at Fort Belvoir. Does "out of Fort Belvoir, Virginia" strictly mean that the helicopter's flight started at Fort Belvoir, or that the helicopter itself is considered to be "out of Fort Belvoir" in a similar manner that LeBron James could be said to be "out of Akron, OH"?

Military flights do not fly ADB hot outside of the DC FRZ. It was also clearly exactly following flight route 4.

There are a few locations in that area it could have been coming from. Anything else would have made no sense flying through the FRZ from/to Belvoir.

What is "flight route 4"?

The FAA publishes supplemental charts specifically for helicopters in areas with high concentrations of helicopter activity: https://www.faa.gov/air_traffic/flight_info/aeronav/productc...

Specifically the Baltimore-Washington route chart was relevant for these flights: https://aeronav.faa.gov/visual/10-31-2024/PDFs/Balt-Wash_Hel...

If you find the DCA airport on that chart, you’ll find routes 1 and 4 which roughly correspond to the helicopter’s flight path.

Right.

Helicopter was on Helicopter Route 4, per the map, apparently on course.

Aircraft was on approach to Runway 33, apparently on course.

That helicopter route crosses the approach to runway 33.

That's controlled airspace. How did they both have clearance to be there?

We'll know more tomorrow as all the audio and radar recordings are examined.

They were almost certainly both cleared to maintain visual separation.

> They were almost certainly both cleared to maintain visual separation.

DCA TWR: PAT25, traffic just south of the Woodrow Bridge, a CRJ, it's 1200 feet setting up for runway 33.

PAT25: PAT25 has the traffic in sight, request visual separation.

DCA TWR: Visual separation approved.

Audio of MID-AIR CRASH into Potomac River: https://www.youtube.com/watch?v=CiOybe-NJHk

This comment was written by a US Coast Guard helicopter pilot. It gives a lot of information on how the two aircraft should have been able to share the space and some speculation on what went wrong:

https://www.reddit.com/r/aviation/comments/1idba8i/comment/m...

That makes sense.

A helicopter instructor suggests that possibly the helicopter pilots, who were told to go behind an aircraft that was landing, were looking at the previous aircraft that was landing.[1] That's just speculation at this point.

[1] https://philip.greenspun.com/blog/2025/01/29/reagan-national...

They could use the car autopilot solution: simply negotiate your coordinates with nearby traffic instead of trying to parse malformed visual data.

That was clearly a training flight

But does that provide any context? Military pilots perform training flights regularly - it's not necessarily indicative of an inexperienced pilot.

Not really. I wasn't a pilot, just a lowly ABF in the Navy. But when we deployed, on an LHD, most of our flights were what you could probably "classify" as training. We ran flight ops every day because pilots have to maintain hours. We flew every day for 7 months and only 2-3 of those months were we in the gulf. And even in the gulf, not all flights were missions, I would say less than half were. That also isn't counting 4-6 months prior to deployment of work ups where we would go out to sea for a week and come back, everyday pilots flew training missions off our deck. All in all, all in the military probably spend most of their air time training then actually flying missions.

I also recall, even experienced pilots, would rotate out to training units as their "shore" (break from a deploy able unit) duty.

This wasn't a Navy aircraft, but I imagine a lot of that is the same regardless of branch.

Note that that track is not ADS-B at all. It’s triangulated from mode S pings (“MLAT”, https://www.flightaware.com/adsb/mlat/). I don’t know how accurate these are.

The current embassy is indeed in DC proper, but it isn't directly across the river from DCA.

It's about a mile upriver, near the Watergate.

It's a "Gold Top", callsign PAT25

https://helicoptersofdc.com/helicopters/5-us-army-12th-aviat...

BBC is reporting that the Army has confirmed that it was a UH-60, not a VH-60, ie: not a VIP transport: https://www.bbc.com/news/live/cy7kxx74yxlt?post=asset%3A62b9...

Although it's early on and these communications are often chaotic/inaccurate.

I thought it was a VH-60 given that it was callsign PAT25 (PAT is Priority Air Transport and they use the VH-60 for those flights), but if this was a training flight, they may have still used the PAT callsign while flying a UH-60.

Both are "Black Hawk" airframes, right? The VH-60 variant is just a UH-60 that was build/configured for VIP transport vs the normal UH-60 utility variant.

IE, other than paint, they look the same to a casual observer.

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