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Out of curiosity, I was wondering how \x93out of the ordinary\x94 the flight path was for PA25 compared to other flights along Route 4. I found 65 such flights in January (there are probably some I missed) and I plotted where they crossed the runway approach. Note that the altitude is binned in 25' chunks, so you should assume that all altitudes just above 200' were actually at 200'. For any aircraft above 200' I DID NOT try to determine if they received clearance from ATC (which is permitted), and you SHOULD NOT assume that they didn't. I also threw in a rough breakout between daylight and night for each crossing. For the two PAT flights well offshore, I did not investigate any special ATC clearances they had. I apologize in advance for any errors as it is a bit tricky to plot and measure these distances.

Added note: The chart shows only crossings collected with ADS-B. I threw out all MLAT collected crossing because of inherent inaccuracy.




Helicopters crossing RWY 33 approach via Route 4 for January

Thanks for the suggestion. I am not a GPS expert either, but it is easy to defend error bars of at least 10' horizontal and 15' vertical (based upon both ADS-B quantization and inherent GPS resolution). I have updated the chart below with those error bars below, and I will update it again if an expert gives me better values. Given your feedback, I would change my statement to say that all depicted values near 200' are consistent with the aircraft being at or below 200', and readers should not assume those flights exceeded the limit.

As for your question on the glideslope, I did NOT properly account for the EGM96 correction. The new chart moves the glideslope up 5' to meet the height of the PAPI as measured in Google Earth (18'), which uses EGM96. Is that reasonable? I should also add a couple of feet to account for the height of the PAPI lights themselves. Does anyone know how much I should add? Thanks for the catch.


Helicopters crossing RWY 33 approach via Route 4 for January (updated)

So it's basically a high stakes game of Crossy Road.

pretty sure I was the circled aircraft that night, AA1855 from CLT. We were just about to be cleared onto the MTV1 when it happened. Did not see it happen but pretty sure we heard JIA5342 being handed off to tower. We were then vectored off the approach and eventually diverted to IAD. Tragic night.

At or below 200ft, per the chart:

This altitude discussion is totally irrelevant to the accident: \x94Do not cross final 33 before CRJ\x94 would perhaps have saved the day.

Here's something I find inexplicable, and relevant to the entire safety case around the mix of airplane and helo ops.

The chart shows the dotted routes connecting 1 and 5 to the Pentagon helipad. But much of the time, the PAT helos would fly the red line - as I observed earlier, over a raised highway with light poles, and cutting under the RW15 approach at about half the distance to the runway end.

I just base this on what I can see locally. I walk almost daily parallel to the rail line and it was no big deal to see the PATs following 395 around the east side of the building - but that's not where the chart says Route 5 is.

By the way a midair over 395 would put debris into a heavily used outdoor sports complex.

PS Observed two more go-arounds from RW18 this afternoon!

https://www.airnav.com/airport/KJPN

FAA Information for KJPN, effective 20 Feb 2025, has amongst Additional Remarks:\x97

CAUTION - TFC PAT - KJPN EAST/WEST OPS. SPECIAL PRO TFC PAT. WHEN LDG W ALL ARR ACFT MAKE LEFT TFC CIRCLING THE PENTAGON AT OR BLW 200 FT. WHEN DEP E ALL ACFT MAKE RIGHT TFC CIRCLING THE PENTAGON AT OR BLW 200 FT

Hiya WR 6-3 , firstly, please do accept my apologies if I came over a bit harshly re ASIAS. I always read you input as, while the detailed legal nitty-gritty is generally way beyond me, you always provide a refreshing viewpoint which is good to read! The aim of my Post, based on my interpretation of the above quote, was just to emphasise the existence of ASIAS is just as a tool or, rather, a set of tools but which has no real "proactive function" in itself. Yes, it represents a very small part of the Flight Safety chain - but as a resource in the main. As you say, there were loads of examples of what happened at DCA and my post was an explanation as to who, I believe, should have been looking at it. Maybe they did - and just ignored it? No idea!

In the UK, the airport operator is totally responsible for the safety of operations on or above their field out to 4000 ft on approach and departure - about 12 miles. The CAA who regulates aviation here, along with the Dept of Transport, but in conjunction with other stakeholders such as NATS (our en-route ATC organsiation), airlines and airfield operators etc, designs the airspace and sets the generic rules for it's use. As you said, the main rule is "Don't crash anything into anything else!". However, at the airfield, it is the airport operator who needs to ensure that the generic rules work in their environment. If a particular rule is legal but, if applied in their location, is unsafe, they can't apply that rule! That's what the Safety Case should say.

A relevant example? I used to regularly (for work) transit London S > N and N > S along the red dotted line below - at 2400ft as it kept me just out of the London TMA but as high as possible so, if it had all gone quiet on the engine front, I'd have the best chance to get the plane onto the ground with me alive and no-one else hurt. As part of the transit, I had to cross the final approach into London City (green line). So, say heading N, I'd chat to Thames Radar while over South London and would ask for a London City crossing. They'd chat to City ATC to co-ordinate and take me to the Thames before handing me to City Tower. My route over the Approach has aircraft at 1200 ft descending on the ILS and so I would have crossed anything landing at 1200 ft above that. So, while on first glance, it was fine I never, ever got that clearance with an aircraft landing - and for very good reasons. If the aircraft on the ILS had had to do a go-around, life could have become interesting very quickly. I was always held until the landing aircraft was well clear (ie ATC could see it was almost at the airfield) before they cleared me across. Indeed, legally, they could have given me a "You see the landing? Pass behind that"! But, no - always positive clearances. Got my vote ....... + gave me chance to enjoy the views of Greenwich and the City of London and "delayed" me a couple of minutes. OK, a bit unfair as LCY is "sleepy hollow" compared to DCA but, despite that, they were very friendly ..... but very strict!!!!!



So, when you are discussing (I think!!!) whether ATC elected to give PAT25 a "You visual? Pass behind" or whether it was "ordered" from on-high as it was deemed safe to do, ultimately, it is the ATCOs call on the day. Now, before I get flamed, do I blame the ATCO ? No! Well, why not? After all, he gave PAT permission! And yes, it was a "legal" clearance. But was it a wise clearance? When unpacking that little lot you have to look at a raft of Human Factors which influenced that ATCO on that night. He was on his own so, probably, the only way he could cope with all he had on his plate was to try and shift some responsibility onto PAT25 - one less thing for him to juggle. But even then, he needed to be monitoring which he clearly was - but while very busy with other approaches and departures so he just picked up a concern too late as the audio shows - "Are you sure you see the jet?". Another factor - was the strategy to use Route 4 while 33 was active something ATCers at DCA, over time, started in an effort to cut down radio traffic and speed things up? If so, had it been assessed and then monitored for adverse safety? While anecdotally, it seemed people were aware of "close calls", had any analysis taken place looking at the Databases? In the UK certainly, all the Airport Operator responsibility.

To the final "accountability" part re payments to families, the thing we have here is (and, folks, correct me if I've got this wrong) the FAA set the rules and the operate the Rules. Here, the CAA sets the rules and the Airfield Operator operates the rules. That is important - for eg, huge argument here in the UK about just how independent the UK's Military Flight Safety organisation is ..... as it is part of the Military. IMHO, what we have here are valid generic rules, some of which were simply not suitable in this specific location - just like crossing London City with an aircraft on approach - legal ...... but very unwise. As to who carries the can, well, as you said WR 6-3 , the legal beagles will get to the bottom of that ..... but it will take some time. I'll leave that side to you!!! My main question out of all of this is, why were not these issues flagged up by airport management for further investigation given it was something of an open "secret"? And where else (around the world) is this happening?

And, on that cheerful note...........! H 'n' H

I keep seeing this picture showing 75 feet of separation but that isn't what it shows at all. It shows way less than 75 feet, right? Maybe the picture isn't to scale but it is the right edge of the heli corridor (the side closest to the airport) that is the closest point, why show 75 feet on the left side away from the airport? It is actually 75 feet on the right side and graphic artist goofed up? Is the 3 degree glideslope nearly horizontal for the duration of the heli corridor so it does not really matter?

See the below post 1180 and some earlier ones:

The horizontal boundaries of the route are not precisely defined. Even then, it's not a very steep slope and the horizontal position does not make a huge difference.

75' is plainly inadequate vertical clearance between two aircraft and doubling/tripling that would still be unacceptably close. Separation was surely expected to be achieved horizontally but the enforcement/implementation was lacking.

For the extreme option , here's a projection onto a water curtain:



The classic 11'8" bridge of youtube fame has overheight lights. The bridge has since been slightly raised and the warning systems improved but still gets people driving straight through them.



Even the London Underground has frangible fittings to detect taller surface stock trains incorrectly approaching a deep-level tube tunnel, throwing signals to danger and thus raising trainstops, which if passed apply the emergency brakes. The latter is important, because SPADs (Signal Passed At Danger) are still not uncommon.


They're not everywhere. It's a risk analysis based mainly on the inconvenience and cost of the cleanup and closure for the bridge/tunnel, and how many overheight vehicles are actually impacting the obstacle. They also don't work especially well because people assume the overheight warning couldn't possibly apply to them .

There's probably some degree of tolerance involved; e.g. bridge marked at 4.4m, sensors at 4.6m, bridge is actually 4.8m. I'm not sure what the actual standards are.

Ohhhh for f***sake

Even worse, this one just posted by VASAviation:

https://www.youtube.com/watch?v=bPQjQ23YTJo

" Delta Airlines A319 performing flight from Washington to Minneapolis was on the initial climb when the pilots received an onboard collision avoidance alert due to a flight of four T-38 Military Jets coming too close for a practice maneuver over the airport."

NTSB chair pointing out the horizontal position of the helicopter during last weeks testimony.
The altitude is still uncertain because of difference between jet and heli values and destruction of the heli altimeter. So work on that is continuing with a focus on other sources.
But note the 75 ft separation is a maximum. So if the heli was at 200ft then it was on the glide slope.




Another interesting point is that mixed heli and fixed wing is forbidden in the yellow zone (permanently), and ADSB mandatory in the red zone. With routes 4 and 6 cut.

See post below

Another interesting point is that mixed heli and fixed wing is forbidden in the yellow zone (permanently), and ADSB mandatory in the red zone. With routes 4 and 6 cut.



another item in the testimony was that generally 100% army helicopters flew there with ADSB set to OFF.

and that the accident heli might have put their ADSB to ON, but that the FAA had not received ADSB data from this heli in 730 days.

on ADSB there also was a difference between the Mike and Lima models,

NTSB chair indicated there was a lot more factual information. I wonder if the pull from Congress will lead to a change in the normal process, and release more factual information (with an appropriate disclaimer).

Related update: Although Route 5 is now technically open, the Secret Lair (to wit, home office directly overlooking the route) has observed no more than a couple of movements since the accident.
Also, note that it is now clearly marked that the flightpath is to the West of the Pentagon. One wonders what the reviewers thought of the Apocalypse Now hard-banking stunts around the east side of the building under the 15 approach.

I know I have been bleating loudly about the visible practice of taking a route to the east of the Pentagon, but here's the latest.

Looks like someone did exactly that today, forcing two go-arounds.

That was what the Army told the WaPo on Saturday:

However, after the Kentucky Derby (decadent and depraved) result, SecArmy tweeted:

Sovereignty > Journalism.
On the track. And in 2025 America.

If there was a VIP onboard, it would be a problem for the Administration.

Now Duffy was on FOX last night, asking to know which VIP was on the helicopter. So apparently not entirely buying the Pentagon version.