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.
https://www.cnn.com/us/live-news/plane-crash-dca-potomac-was...
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.
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.
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.
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.
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
https://www.reddit.com/r/aviation/comments/1idba8i/comment/m...
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...
It's about a mile upriver, near the Watergate.
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.