Posts about: "NTSB" [Posts: 232 Page: 3 of 12]¶

Subjects NTSB

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Subjects CRJ  NTSB

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Subjects CRJ  NTSB

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matching the info from the NTSB transcript briefing to the ADS-B trajectory:

Quote:

Originally Posted by Sailvi767

Regardless the TCAS almost certainly gave them a traffic alert while above 500 feet

exactly at 500ft it seems

Quote:

Originally Posted by Sailvi767

and displayed the traffic all the way to impact for the RJ crew.

to put "all the way" into context, 18 seconds is what they had

Subjects ADSB (All)  NTSB  TCAS (All)

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Quote:

Originally Posted by JohnDixson

Dibo/fdr: keep wondering why the Hawk crew made that last correction to the right.

I don't think it make a significant turn right, and I believe that what you are seeing is positional inaccuracy due to MLAT position limitations in the ADS-B Exchange data. According to Flightradar24, " MLAT position calculations have a general accuracy of 10-100 meters and 1000 meters in the worst cases." Given that, I believe this previous post from MikeSnow AA5342 Down DCA represents our best current understanding of the actual helicopter track and its relation to Route 4 (until we get more information from the NTSB). I generated my own zoomed overlay and got essentially the same results



The position of the collision shown in the radar data overlay is consistent with the position of the RJ as shown in ADS-B Exchange at the time of the collision (approximately 01:47:59Z according to the NTSB timeline). See this link from DIBO for the RJ Track with timing AA5342 Down DCA In my experience, times in ADS-B Exchange are generally accurate to within 2 seconds. Given all that, I believe that the Black Hawk was within the horizontal bounds of Route 4 at the time of the collision and that it did not make the right turn we see in the ADS-B Exchange map.

Edit: Corrected route number and helicopter

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Last edited by airplanecrazy; 6th February 2025 at 01:24 .

Subjects AA5342  ADSB (All)  Blackhawk (H-60)  DCA  NTSB  Radar  Route 4

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Subjects CRJ  NTSB  Separation (ALL)  Vertical Separation

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Subjects ATC  CRJ  Close Calls  DCA  NTSB  Night Vision Goggles (NVG)  Pass Behind  Pass Behind (All)  Route 4  TCAS RA  VFR

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Subjects DCA  NTSB  TCAS RA  VFR

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Quote:

Originally Posted by T28B

A quick note for dbcooper:
The accident investigators will probably be asking questions similar to yours, and a great many more.

As to Dulles and rail: I am happy to inform you that the metro now goes out that far .
I had heard some years ago that the Metro was eventually going to get out that far into Northern Virginia, and it seems that "eventually" has arrived.

It does. I've been visiting a friend in Reston for 30 years and one day, quite recently, Metro was just "there."

Quote:

Originally Posted by Torquetalk

Now, if the article made that point clearly, and did not concern itself with:
[stuff]
But as it was a blatantly political article that did not focus at all on the key things that are pretty much obvious as causal from this discussion, then it is surely just a distraction to serious discussion in this thread.

The controller does not appear to have done anything wrong, so what have DEI policies to do with the ATC side of this accident?
The passenger aircraft followed a procedure and got hit, so what bit of the federal bloat caused that?
The 2-crew helicopter apparently never properly identified the aircraft they were supposed to avoid visually. You going to really argue that the DEI or the government caused that?

Unsafe procedures caused this. SASess, please take the ridiculous politics to Jet Blast.

Avoiding the partisan finger-pointing, I'm going to generally agree here.

We all know there are issues with American ATC. But primarily, they are ordinary problems that don't need radical solutions. The solutions are generally more resources and more rigorous enforcement.

* One of my go-to complaints: Pilots not disciplined for erasing or overwriting CVRs following runway incursions and near misses. No blowback for aircrews refusing to meet with NTSB following incursions/near misses. I mentioned this earlier; hopefully 25 hr recorders will fix the overwrite part of this. Ideally the "erase" button would be removed in all cockpits where it still remains. I understand aircrews wanting to erase their CVRs and avoid meetings with investigators after doing something careless (or straight up idiotic) with a plane full of people, but, folks, how can coming to Jesus *not* be part of the job? We are blessed to live in a country where fatal transportation accidents are not presumed to be criminal (unlike most every other non-Commonwealth nation), and aircrews hardly ever have personal liability for damages. Yes a career might take a hit. That's careers for ya.
* Runway incursions in general: Over 1k per year for many years ... we have systems to manage this but they need to be continually funded, resourced, and improved ... HNL, MDW, LAX need to be sorted out aggressively (LAX is no longer the poster child for incursions, good work there, it's HNL now)
* See-and-avoid: It works as well as it does because of the very high standard of air"person"ship prevalent in the US, but it is absolutely guaranteed that see-and-avoid is insufficient to avoid midair collisions, as it is impossible to see all potential collision aircraft even in broad daylight
* Manufacturer quality: Until MCAS I'd have never thought that US manufacturing processes would (once again) become a significant safety risk, but, here we are, with no indication that the trend has been reversed (it's fair to say that there is some promise that there has been a reversal at the top of Boeing management, but effects haven't appeared at this early date)
* ATC hiring: Pay more, hire more, create alternative career structures that allow qualified "old" people in their 30s to start jobs at ATC while giving them a fair framework for retirement

None of this needs "AI" or "satellites" or "complete rework" or "woodchipper" to fix. It just needs money and constant re-commitment to safety, and commitment to compromising in favor of safety when a decision of "revenue vs safety" arises. Honestly I think it's mostly about money. Perhaps 99% about money. Perhaps 100%.

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Last edited by remi; 6th February 2025 at 22:31 .

Subjects ATC  Accountability/Liability  Close Calls  DEI  NTSB

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Subjects AA5342  ADSB (All)  NTSB  PAT25  Situational Awareness  TCAS (All)

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Subjects AA5342  ADSB (All)  ATC  Blackhawk (H-60)  CRJ  DCA  NTSB  PAT25  See and Avoid  Situational Awareness  TCAS (All)  VFR

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Subjects AA5342  ADSB (All)  CRJ  NTSB  PAT25  TCAS (All)

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Subjects AA5342  ADSB (All)  NTSB  Night Vision Goggles (NVG)  PAT25  Situational Awareness  TCAS (All)

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Subjects NTSB

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Subjects CRJ  DCA  NTSB

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Subjects ATCO  NTSB  PAT25

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Quote:

Originally Posted by henra

First of all: I can largely follow your Maths. In a straight line the PAPI is a bit less than1550m from the Eastern bank of the Potomac on a straight 328\xb0 course. At 3\xb0 this would be 270ft altitude when crossing the -east bank. Both aircraft ended up in the Potomac. When looking at the point of impact of the Blackhawk in the Potomac in these videos I end up with a spot ~1450m from the PAPI.
On the other hand the collision will have somewhat altered trajectory of both aircraft, so maybe the collision had still occured over land and due to the lateral energy transfer the Helicopter was thrown off its original course towards the West and into the river. We will get this information finally.
And in the end it doesn't really make that much of a difference wrt the level of lunacy of this whole setup.

I think the collision was closer to 1250m (4100') from the PAPI. I base that upon the NTSB statement " At 8:47:58, the crew had a verbal reaction, and FDR (flight data recorder) data showed the airplane beginning to increase its pitch. Sounds of impact were audible about one second later," That puts the collision at about 8:47:59 (01:47:59Z). ADS-B Exchange data at that time puts the ground distance to the PAPI between 1200-1280m (3900-4200'). My assumptions are that the NTSB statement is correct and that the ADS-B Exchange data is accurate (which in my experience, the times are generally less than 0.2 seconds later than the timestamps on data collected by the FAA, and the reported NACp (position accuracy) was estimated at < 10m). Here is the graphical representation I generated of my estimated collision position vs. PAPI.


Collision Altitude vs PAPI

Quote:

Originally Posted by galaxy flyer

Having been in a mid-air collision with similar geometry, I would bet it was only normal input to approach path. FDR’s are incredibly sensitive recorders. I have a vague memory of the other plane’s wing flashing by. It looks slow in the videos, but it’s incredibly fast.

If my depiction is accurate, it's hard to see why they would pitch up as normal input to approach path. I think their inputs would have been focused on getting down.

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Last edited by airplanecrazy; 11th February 2025 at 06:30 . Reason: Problem with picture. Awkward phrasing

Subjects ADSB (All)  Blackhawk (H-60)  FAA  NTSB

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Subjects ATC  NTSB  PAT25

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Quote:

Originally Posted by SLFstu

I’m not sure your quoting FAA helicopter routes as having no defined centreline or width would strictly apply in DC versus what they wrote about the North Shore of Long Island route in NYC where they are required to be 1 mile off the shoreline. As shown on the published helo chart (DIBO’s post #863, and your little chart insert) and in writing (BuzzBox’s post #998) Route 4 directs traffic to track “via the east bank of the Potomac” from the Wilson Bridge to Anacostia River. If the impact point was 1000 feet or so (give or take some trig) from the east bank of a 3000 feet wide river at that point wouldn’t this mean that PAT25 was not only too high but off track too? Otherwise according to your graphic even at 200 feet max elevation, being that distance from the east bank any helicopter not maintaining visual separation could collide if an AC was still positioning itself from being low on the glideslope.

My understanding is that the FAA depicted width of a helicopter route is governed by the following doc: https://www.faa.gov/air_traffic/flig...2-complete.pdf . It specifies that on a fully printed chart the route should be 0.1 inches wide regardless of chart scale. The chart I pulled from was 1:125,000 scale (full chart size is 51x33 inch poster), which would mean the routes "appear" to be 125,000 * 0.1 / 12 = 1,042 ft wide. In the same FAA chart package https://aeronav.faa.gov/visual/12-26...-Wash_Heli.pdf , the third page is a "Washington Inset" with a scale of 1:62,500. In that inset the routes "appear" to be 62,500 * 0.1 /12 = 521 ft wide. Also, if you look at the centerlines of the routes depicted on those two pages (which I "drew in" below), they do not exactly match. For example, look at how the full chart shows the route going east of Hains Point while the inset shows it very close to Hains Point.


DCA Helicopter Routes

Given these chart differences, I wonder how far a helicopter can stray from the various depictions of a route before it is considered a pilot deviation? Perhaps the NTSB will give us some insight with their accident report.

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Last edited by airplanecrazy; 14th February 2025 at 23:53 . Reason: Emphasize the route "appear"

Subjects DCA  FAA  NTSB  PAT25  Route 4  Separation (ALL)  Visual Separation

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Quote:

Originally Posted by airplanecrazy

My understanding is that the FAA depicted width of a helicopter route is governed by the following doc: https://www.faa.gov/air_traffic/flig...2-complete.pdf . It specifies that on a fully printed chart the route should be 0.1 inches wide regardless of chart scale. The chart I pulled from was 1:125,000 scale (full chart size is 51x33 inch poster), which would mean the routes appear to be 125,000 * 0.1 / 12 = 1,042 ft wide. In the same FAA chart package https://aeronav.faa.gov/visual/12-26...-Wash_Heli.pdf , the third page is a "Washington Inset" with a scale of 1:62,500. In that inset the routes appear to be 62,500 * 0.1 /12 = 521 ft wide. Also, if you look at the centerlines of the routes depicted on those two pages (which I "drew in" below), they do not exactly match. For example, look at how the full chart shows the route going east of Hains Point while the inset shows it very close to Hains Point.


DCA Helicopter Routes


Given these chart differences, I wonder how far a helicopter can stray from the various depictions of a route before it is considered a pilot deviation? Perhaps the NTSB will give us some insight with their accident report.

"...FAA depicted width of a helicopter route is governed by the following doc: https://www.faa.gov/air_traffic/flight_info/aeronav/iac/media/IAC15/IAC-15-22AUG2022-complete.pdf "

I think that the "width" that you are referring is for the chart maker but not the actual width of a helicopter route.

I can't find in any FAA document a definition of the lateral extent of a helicopter route. Is there one?

There are inconsistencies between the "DESCRIPTION OF ROUTES AND ALTITUDES" and the charts themselves. The Merriam-Webster's 11th Collegiate Dictionary definition of "BANK 2 : the rising ground bordering a lake, river, or sea or forming the edge of a cut or hollow."
for example "RT. 4: ... VIA EAST BANK OF POTOMAC RIVER..." while the chart depicts RT. 4 over the POTOMAC RIVER not over the ground bordering the river.
while "RT. 15: ... ALONG THE WESTERN SHORE OF THE CHESAPEAKE BAY AND PATAPSCO RIVER..." and the chart depicts RT. 15 over water.

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Last edited by airman1900; 11th February 2025 at 22:33 . Reason: punctuation and quote

Subjects DCA  FAA  NTSB

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