Posts about: "ATC" [Posts: 614 Page: 24 of 31]¶

As a non-professional here, I assume I am missing something obvious... would someone please educate me as to why the DCA restrictions include the 1200nm limit? I am not seeing how distance traveled prior to approach would impact local congestion, ATC workload, or anything relevant. Just looking to fill a hole in my understanding.
Thanks in advance

Hi WR 6-3 , I've been following discussion about immunity etc - I'll steer clear of that legal discussion if I may. I have no idea \x96 I\x92ll leave it to you bright legal folks!!! However, with a humble background in Safety Engineering, and having been on a few Flight Safety Committees, and even run a large UK Database used by Equipment Engineers (I just ran the system \x96 a very important point as you\x92ll see later!) to identify Engineering issues with their kit, my thoughts. I\x92ve no idea how things (a) should have worked at DCA and, (b) actually worked there. But what follows is how I\x92ve seen it working countless times when I\x92ve been part of that process at different levels in the UK. Just some thoughts really\x85\x85 and you\x92ll see why I\x92ve underlined the bit above shortly.

Personally, the reference to ASIAS and it forming a key player here is, IMHO, a bit of a "red herring". It's not how Flight Safety should work in my experience of over some 40 years. Flight Safety ethos comes from the top and works down. Flight Safety activity starts at the bottom works up. In other words, it is the guys and gals on the Line, in the Tower, in the Hangar, in the Cockpit day-to-day who should actively spot and flag up issues relevant to where they are working - encouraged and supported all the way by the ethos from on high. After all, they (and only they) know exactly what is happening in their airspace, on their flight deck, in their hangar.

So the \x93DCA Flight Safety Organisation\x94 (we had Flight Safety Committees as Sqdn and Stn level to manage this \x96 similar in Industry \x96 so does DCA have a similar group? Please tell me it does!) should have been alerted to, possibly, initially unquantified issues with near misses along Route 4 by ATC staff. Local DCA Safety Management and ATC staff would then quantify the issue using the data available directly from such sources as the FAA AIDS and the NASA ASRS databases, all freely available via the ASIAS site. A good overview of ASIAS can be found here and an example of a search screen is the AIDS search form. This is all driven \x93bottom up\x94 . I personally used AIDS and ASRS during my MSc when writing a research paper many years ago \x96 sat at my PC in the UK so it\x92s really easy to use if I could master it! Juan probably got his stuff from there too.

Once the \x93DCA Flight Safety Organisation\x94 has looked at the data sources, either you have no issue or it needs wider investigation. In this case, clearly it was an issue, so (a) Route 4 should have had temporary mitigation put in place by DCA and (b) the "corporate" FAA (for want of a way to describe it) should have been requested to carry out a full "independent" Safety Review. Finally, (c), the ASIAS organisation could have been asked to flag this up to other Airfield Safety Organisations in their \x93Communication\x94 role in case they had similar issues to DCA. Again, local Safety Management at those fields would then investigate.

The FAA Safety Review should decide, with justification , what the next steps are - the justification being called the revised Safety Case (\x93revised\x94 as there should already be an initial \x93Safety Case\x94 supporting the operation of Route 4! Mmmm, an initial Safety Case? Was that a pig I\x92ve just seen fly past here???????!!!!!!!!). The outcome could be (as in this case) to close Route 4 down. If it were to be kept open, the revised Safety Case must support that by adding further mitigation and, vitally, the situation should be then be formally reviewed at defined intervals to ensure such mitigation is actually working before it becomes \x93normal business\x94. The FAA could also order a much wider formal review to see if other airfields are similarly affected and, if so, similar Safety Case reviews should be conducted at such locations if required.

So, from my point of view, I think that ASIAS (and as per the ASIAS overview link earlier) is not in itself responsible for initially identifying issues - it is simply (a) a conduit across users once issues have been identified by a user and (b) it manages some tools for users to use. I managed the RN\x92s Fleet Air Arm Engineering Database with a staff of 3. What we would do is, for example, at the request of Equipment Desk Officers , run additional reports requested by them if they thought, say, there was an increase in issues with a particular type of hydraulic pump or whatever it was. It was not my role in that Post to look for problems - my role was to ensure such data was accessible and ensure the database remained accurate and up to date. As I said earlier, the activity to raise problems and initially scope them is bottom-up as only the worker-bees (in my example, the Desk Officer) see the specific issues where they happen to work. The ethos to ensure that the organisation is in place at each airfield (and the wider FAA) to support the Safety activity should be top-down.

Clearly, it requires suitably qualified/experienced people on the coal face with a mind to safety to actively recognise and flag up such issues, encouraged from the very top by the ethos . That is an important point. If the ethos \x93encourages\x94 the watching of a \x93near miss\x94, sucking one\x92s teeth and saying \x93Sheesh! That was bleep-bleep close!!!!\x94 and moving swiftly on, that is NOT a safety management ethos !!! That is a recipe for disaster! If the ethos exists only in name and the worker-bees are not positively encouraged to raise issues which are then transparently acted on, but is an ethos which is totally subservient to commercial or political pressures then you'll get little or no Safety activity which will lead to\x85\x85\x85.... I\x92m sure you can all fill that ending in\x85\x85\x85!

Just my thoughts FWIW\x85\x85.. and sorry it\x92s so long! Cheers H 'n' H

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

H & H:
". . . 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?"

To start, no apology whatsoever needed with regard to this dialogue. I try to respect the decorum required on this forum generally (meaning as SLF/attorney something has to be pretty severe or awful to warrant apologizing to me). And although I might not explain my sense of this with enough clarity - the FAA is conducting a review (according to Secretary Duffy) of airspace management and usage rules at other airports. The explanations in your posts, including very particularly the procedures when crossing approach corridors for London City, should be read and studied by the presumably well-informed professional ATO (Air Traffic Organization) staff assigned to conduct the review. (If it seems way presumptuous for an SLF/attorney to assert what resources ATO should be considering for the review noted by Sec. Duffy, I would suggest that ATO's reputation at the moment for upholding the much-touted "gold standard" set by FAA and United States aviation in general for the rest of the world ... well, like we used to say in trial practice, it takes the other side only about three minutes in court to stain the draperies, but it will take us all afternoon even to try to clean them. Reputation lost, same deal getting it back.)

On ASIAS, actually I entirely agree with your description of where it fits into the so-called "aviation safety ecosystem" (there simply has got to be a better term). The point I'm stuck on is one that (apologies, once more) comes from litigating in U.S. courts (especially federal District Courts around the country) employment law cases. Specifically, at the start, the main task for defense counsel is to construct the "chronology". Who did and said what to whom, when, and for what reason(s). I've asserted in an earlier post that in what I see as the inevitable litigation arising from this accident, there will be teams of significant lawyers constructing, or attempting to construct, such a chronology, although it won't be about an individual employee's hiring, performance reviews, promotion grants or denials and so on. It will be how it happened that the situation which obtained in the DCA airspace, in the cockpits of the Blackhawk helicopter and the CRJ, and ATC, came to exist.

(And I say "significant lawyers" because the attorneys who handle the big and significant aviation crash lawsuits for the families of victims are kind of the polar opposite of the stereotype ambulance chaser; to the contrary, their work is opposed by big-time big-law firm skyhigh hourly rate legally privileged sharks. The lawyers suing on behalf of these crash victims - if they are the same as the legal specialists I have met and discussed stuff with in various settings - are vindicating the need to bring the truth to light. "Aviation is the safest form of transportation": it is incanted over and over to the point of making anyone who utters it now sound quite seriously performative. Yet if it is so safe, how and why did those 67 people die over and in the Potomac? So with a kind of intense ruthlessness, the lawyers who will represent the families and other loved ones of the crash victims will unearth every little sequential act and omission which led to the situation which obtained on the fateful night of Wednesday, 29 January 2025. Exactly as the quoted language above from your post asks, what indeed was the strategy, if there even was one, as opposed to little incremental changes, accelerated of course by increasing airline flight lengths under the perimeter rule.)

On this basis, I would not concur with the idea that whether immunity is available for the defendants (both the Army and FAA/DoT) depends on whether the ATCO's specific conduct on Jan. 29 was "ordered" from on-high. The "on-high" is the development, over time, of the situation that obtained that night at DCA, despite safety imperatives in the NAS and aviation sector in general - and not a specific order or instruction given on that night.

The question behind the discretionary function exception is whether the act or omission by the defendant either (1) was negligent because it failed to follow a specific rule or statutory provision (if so, no immunity), or (2) was negligent in the usual sense of the word but will nevertheless still be protected by immunity because the act or omission was based on a decision about a policy matter or question. The decision on the policy matter or question is "discretionary" on the part of the government and hence the name of the exception protecting it. The courts are reluctant, and sometimes loath, to second-guess policy decisions made by the Executive Branch (I know, irony neither intended or not intended, given certain prominent flight- and aircraft-related matters in federal court at the moment). Under the first variety of negligence, there was no policy matter being decided, just failure to do something there was a legal duty to do (basic definition of negligence). Under the second variety, there would be a valid case to be made that there was negligence - but the immunity provided by the exception for discretionary functions prevents the case going forward.

So back to January 29, the assertion I've been making here is that no, there was not a specific rule or procedure that said to do things much like you describe the procedure - de facto (unwritten, informal) though it was - for transiting across the approach path. But there certainly were higher-order rules by which FAA and its ATC functions were required to observe in consistent performance, and not merely in repeated incantation that "aviation is the safest form of transportation." In fact, I wonder if clever lawyers might take that slogan and deploy it as a bludgeon. "You're at greater risk driving your car to the airport", they always say. Oh, really? Then let's talk about the equivalent scenario on the streets of Chicago with intersecting traffic lanes (obviously not at different altitudes), similarly difficult visibility conditions at night, compounded by NVGs. possibly compounded by a training or check ride in the vehicle, and then make the case that the Chicago PD cop directing traffic, and the motorist without the right-of-way, were acting on the basis of interpreting policies about driving on public roadways. No, there is no policy matter involved - there are strict rules of the road and over-riding principles for safe driving, and the failure to observe these is negligence.

It's simplistic but it might be sufficiently illustrative. Is "see and avoid" a procedure which involves making decisions on matters of policy? or is it a higher-order safety rule which must be observed at all times?

(Not meaning to slight the point about ANSP and regulatory functions needing to be separate - entirely agree, and yet, this will be an extraordinarily heavy lift to get done in the United States. That being said, I might know some lawyer-types who are fired up about efforts to make it happen this time around.)
WillowRun 6-3

Was the controller really on his own?

The local controller had an Assistant ATC and a Supervisor to coordinate, monitor and regulate the traffic.

Class B airspace "ATC Clearances and Separation. An ATC clearance is required to enter and operate within Class B airspace. VFR pilots are provided sequencing and separation from other aircraft while operating within Class B airspace." source FAA Class B
One way to determine how the application of sequencing and separation to VFR pilots in this airspace was being applied would be to listen to the audio and watch radar replays over the weeks and months prior.

By Airport Operator do you mean the airport itself or the ANSP?

Hiya WR 3-6 , thanks for your reply. A busy day today so I'll give this more time tomorrow if I may! But interesting points again - and I'm a bit clearer too on this "discretionary" aspect - I think!!!!

Hi missy , sorry, what I was trying to say was, and this is from further back in the Thread, it is my understanding that often there is 1 controller handling main arrivals & departures with another controller handling local traffic on the heli routes etc. As is often the case, at quiet times, one position closes and so the 1 controller is now controlling both. That is very common practice both at airports and en-route. The others are, indeed, there in support but things happen (eg the Supervisor is asked a question or gets a phone call - similar with the Assistant.). Not saying that happened here but it illustrates the support aspect of those roles and what can happen.

Now, one could say, "Well, there was a fairly steady flow of (maybe) 10 aircraft landing/taking off. So, 1 extra helicopter is not much more to add in!". True ...... but ...... an example. A mainline train arrives at a major London Station and, at once, all the doors open and several 1000 people all get off together and start heading up the stairs to the ticket barriers. The flow of traffic is heavy but quite ordered as the flow is all in one direction and so, while traffic density up the stairs maybe slows it down a bit, the flow is nicely ordered. Picture now, H 'n' H , being in a rush and so being one of the first off the train arriving at the ticket barrier only to realise - Durrrr - he's left his case back on the train. Being not-too-bright, I decide the quickest way to go back is down the same stairs I came up, and hence back to the train. Of course there's only 1 of me going down and several 1000 coming up. But to an onlooker gazing down, the effect of my single trip back against the several 1000 heading up has had a significant effect. TBH, H 'n' H is causing a fair degree of chaos as he pushes past everyone fighting his way back down the stairs against the flow. A few choice comments are being made by his fellow pax! What we have is a disproportionate effect caused by 1 vs 1000's.

So, while I'm no expert in how the brain works, usually the ATCO is dealing with a steady flow S - N and is sequencing things in their mind to smoothly land and depart traffic, slotting people in and out of the queue to achieve an orderly, safe, flow. All of a sudden, their "mental flow" now has something working in the other direction which all needs a bit more thought to ensure that everything remains safe. OK, 1 helo is not much, but it requires a disproportionate amount of extra "computing" compared to, say, adding another 1 aircraft into the main flow, to ensure safe separation. Was that why the "Own visual separation" offer was taken up? Now, rather than managing the contraflow, the ATCO only has to "monitor" the singleton swimming against the tide - which they were to a degree. Just a thought.

Spot on! I'm not sure how long such tapes are kept? Usually it is a defined period after which the tape is recycled into the "system". Of course, looking further back, and in a perfect world, you could assess ATC SOPs against the buildup in traffic over the years and see how that's affected things over time. Was it the case of "a death by a 1000 cuts" which WR 3-6 cited? Sadly, I suspect we'd need a crystal ball to study that. But retired Controllers could give a fairly good insight.

I mean the Airport Operator running the airfield. So, in the UK, that could be a company who then employ the Twr controllers to run that side just as they employ or contract Baggage Handlers, Cleaners, etc, etc. The UK ANSP (NATS) generally pick up everything above 4000 ft tho the actual hand-offs vary tactically and there can be local variations to suit specific airspace. So, for example, from memory, the Channel Islands work up to a higher level before en-route takes over. Below that, its up to the Airport Operator to staff their operation and make sure it's all safe and sound.

Anyway, better dash as already late........! Before yet more chaos is caused by H 'n' H !!!!!!

Hmmm. I'm going to extend your Chicago traffic analogy. Imagine that traffic regulations permitted things known to degrade safety, but which at least some road users wanted: heavily tinted glass, freedom to use handheld cellphones while driving, higher levels of blood alcohol etc. Would the resulting accidents be down to negligence of drivers for being insufficiently skilled to avoid causing accidents under the prevailing regulatory conditions, or down to negligence of the regulators for permitting obviously less safe things to please certain parts of the road user community?

Of course in this case the thing known to degrade safety is "see and avoid", the regulator is the FAA, and the relevant parts of the user community appear to be "near as damn all of it". Focusing on the Army pilots' failure to achieve it would be a neat distraction from the much more difficult question (for everyone) of whether it is an appropriately safe means of separating from airline traffic. The nice NTSB diagram of Route 4 and the 75 feet spacing dodges the issue that neither the controller nor the Army pilots assumed that procedural separation existed; visual separation was being applied.

The permanent closure of Route 4 could be seen as acceptance that this was an unsafe basis on which to permit operations. However it still misses the point. The route was capable of being operated safely, for instance by holding helicopter traffic or avoiding use of runway 33 when needed to prevent conflictions, but that would have been tacitly to accept that visual separation was unsafe. Closing the route also only fixes the issue on one runway at one airport. Where next?

H 'n' H:
"[L]ooking further back, and in a perfect world, you could assess ATC SOPs against the buildup in traffic over the years and see how that's affected things over time. Was it the case of 'a death by a 1000 cuts' which WR 3-6 cited? Sadly, I suspect we'd need a crystal ball to study that. But retired Controllers could give a fairly good insight." (emphasis added)

Probably five dozen lawyers have added, or will add, to their work-in-progress plans for their fact investigation and discovery activities locating, interviewing, and taking the depositions of retired ATCOs - with pertinent knowledge and appropriate credibility and experience, of course.

Not from a retired DC controller but from a current one , quote taken from another ATC forum :
The bold additions are mine . Just that we are absolutely clear , those are opinions , not facts .

Hi WR 6-3 , thanks for that - I think I've finally got the idea here! I've been particularly slow on the uptake and, on that basis, you are correct to reject my "on high" example. I've said much so time for me to sit back - there seem to be so many issues with this case and this "immunity" question is just one aspect to it and which I found difficult as a non-US and non-lawyer to understand. Engineering (my first "life") is far easier - if it doesn't work, you hit it - if it still doesn't work, you just hit it harder! Simples!!!!!

My closing thoughts. It seems ATC were simply trying to run a routing system, the layout of which was handed to them, to the best of their ability. As moosepileit said at Post #1176, "These charted routes are Pre 9/11/01. ATC workload and growth of route, ahem, users, too. How do you boil a frog? Just like this. One degree at a time. This is the B-17/P63 crash - dumb orchestration, no one spoke up." . The ATCO involved seems to be a victim of this - a process of "normalisation" over time and pushing rules to, or beyond, their sensible limits - something I said a few Posts back. Similarly, the helo crew were as much victims - again, possibly a process of "normalisation" over time meant they were a bit too happy to say that they had an a/c in sight which they genuinely thought was 5342 but wasn't - "normalised complacency" if such a term exists - I guess it does now!

My own concerns relate more to the "human factors" involved (as per my Safety Engineering experience) and why someone, somewhere, didn't call "Time-out, Folks! We seem to be having a lot of near-misses here! Time to revisit the Safety Case!" - if there was ever one in the first place....... Interestingly, I've already mentioned the Airport Management team in this context - but how come the airlines, where some of their pilots are calling DCA, what was it, "the most dangerous airport in the USA" (it's somewhere back in this Thread!), didn't call a halt? They also have a responsibility to conduct safe operations. OK, they have less exposure to the rate of TCAS warnings at DCA but someone, somewhere would review all TCAS incidents involving their aircraft, where it was and, importantly, why it occurred........

I hope that, once complete, the detail of their findings are written up and presented formally to the Aviation Community. The ultimate irony is that your fellow legal-beagles will be doing work which should have been done by Flight Safety people in the first place ! The only difference is why they are doing it! As someone who has had a formal background in Flight Safety, that is really quite embarrassing!

To close - I was involved in one "incident" (actually, it was a complete "non-incident" as you will see!) when crossing the overhead of Luton at 3000ft S - N one day. A jet on the runway went tech so the next aircraft on approach, after some discussion between ATC, the stranded aircraft on the r/w and the aircraft on approach, had only one option - to go around as the runway was blocked ...... certainly for a while. Standard missed approach for LTN is (simplified) "climb to 3000ft" - exactly where I was. But The reason I'd been given that crossing clearance was the ATCO had clearly pre-planned for the eventuality of me being overhead at 3000ft and a possible go-around to 3000ft. His instruction was quite straight forward, immediate and totally relaxed. "Airline XYZ, go around - stop climb at 2000ft - traffic crossing in my overhead at 3000ft.". Even so, I did pay very close personal attention to the go-around a/c, checking it actually leveled off at 2000ft ...... to see that it all went according to the "Plan"! Oh, in case you wondered, the big difference between my LTN and LCY crossings was that I couldn't get high enough at LCY for ATC to safely slot just this sort of go-around in underneath me! At LCY, the London TMA limited me to 2500 ft max (well, 2400ft with 100ft to allow for height-keeping errors on my part!).

But at LTN, I did have a great view of a 737 climbing towards me, leveling off and then passing safely below! If only the outcome on that fateful night at DCA had been the same for 5342 and PAT25.........

Hiya Capn , that is precisely what I've been saying in my last few posts (while waiting for various builders and plumbers to get back to me!) - have a look at my last few posts. It's also worth reading Post #1365 by layman54 re aircrew to which I was responding - hence the limited reply I gave concentrating on the topic their post had raised.

My view - they were specifically asked to visually identify a/c A. Now, given the stream of a/c, the distance the a/c were away, the angle of the stream, etc, etc how could they reliably pick out a/c A? Almost impossible I'd say. But they said they had, which then formed the basis of the clearance. But, as you say, they were actually looking at a different a/c, a/c B, not deliberately, but mistakenly thinking it was the one ATC had asked them to look out for and pass behind, a/c A.

You are spot on in that there was no way for ATC or the helo crew to verify that the one the helo crew were watching (a/c B) actually wasn't the one that ATC thought they were watching (a/c A). That, as you say, was a very significant weakness. So they were on course to avoid the one they were watching. But that wasn't the one ATC had asked them to watch.

You are dead right in how difficult "see and avoid" is. I'm lucky as I only flew between small UK Regionals and, particularly when in my home patch, I often got from Twr "Visual with a/c A on Final? Join Final as #2 to a/c A!" type stuff. Worked OK when it was only me and a/c A. Any more and usually Approach sequenced me if I'd arrived SVFR by placing me under Radar Control for a short while before then handing me off to Twr to join the cct visually once faster traffic was well ahead of me. That's if they didn't forget me completely .... which happened once ...... but that's another story - they were most apologetic when I reminded them I was still on the last vector they'd given me!!!! "Sorry about that, I'd completely forgotten about you!"! Charming!

" My view - they were specifically asked to visually identify a/c A. " is incorrect.

The helo crew asked ATC for visual clearance and ATC agreed. It is not clear why the helo crew made the request nor how they missed that an aircraft switched from crossing their field of vision to one that became fixed in their field of vision, but it is likely the bias of certainty in their mental model of which direction they needed to look did not include towards the side.

Hi MechEng , it's been a while since it was discussed.

Here is the NTSB report/transcript and another transcript here . I couldn't locate the one on Prune way, way back but these 2 will do!). ATC specifically call the a/c sidestepping to 33 as the a/c PAT needs to identify. The ATCO even tells PAT what type it is. PAT then say they have "it" visual. Sadly, "it" wasn't the sidestepping a/c, it was another one. But no-one figured that out ...... till seconds before the crash. This initial exchange, according to the transcript, was about 2 min before the collision. It's only then, on the basis that PAT says they have seen "it" and, by implication, will visually avoid it, that ATC issue the clearance on down Route 4.

There was a lot of discussion earlier on in this Thread about how on earth PAT could be reliably expected to pick out the subject a/c from the rest of the stream of arrivals and at that distance (6 miles rings a bell).

It's only seconds before the crash that it appears that the poor ATCO suddenly starts to suspect the PAT crew are actually looking at a different a/c to the one he had asked them to identify and pass behind. But, by then, it was too late for him to figure out a solution to give to PAT.

As I said, this was all discussed many posts ago so it's easy to forget the details. Hope the links help!

Cheers, H 'n' H

I think it's also important to recall from way upthread that at the point of being called as the factor traffic by ATC, the CRJ and the AAL aircraft behind it in the stream were extremely close together in the helo pilots' field of view, because the circling manoeuvre had barely begun. A very illustrative diagram was composed by a YouTube contributor (not one of the usual aviation commentators) which made the point very well. I'm mildly surprised the NTSB didn't produce such a diagram of its own at the initial report stage.

Taking that concept a bit further, it is unlikely that one or both helo pilots maintained continuous visual on the called traffic after the initial \x93traffic in sight\x94 confirmation given their high visual workload (other traffic scan, visual navigation, maintaining altitude). A possible scenario is that one or both of the helo pilots did visually acquire the CRJ on the initial traffic call, briefly broke visual contact, and then subsequently acquired visual on the wrong traffic, maintaining that incorrect traffic contact until the collision. My recollection when I ran some geometry from the initial CRJ traffic call is that CRJ and AAL (or other traffic in the stack) would have differed in azimuth by about 3 degrees.

Not sure what right turn you\x92re referring to. Figures 2 and 3 of the NSTB preliminary report show PAT25 tracking parallel to the eastern shore of the Potomac River at the time of the collision. Because this shoreline tracks a line about 200/020 true, PAT25 had to turn to the right after passing Hains Point track Route 4 and that\x92s what the track shows.

I don’t think the radar track shows a last-minute right turn turn by the helo (I looked at the post #848 image). The NTSB preliminary report states the helo had a 1.6 deg left bank at the time of the impact. Although the report notes the evasive maneuver by the CRJ (elevator, pitch), there’s no mention of evasive maneuver by the helo. I think you might be biased by some of the early but inaccurate MLAT tracks that showed a significant right turn by the helo prior to impact.

Dumbo Question 2

Given the extraordinary level of interest in the US Army Blackhawk carriage, activation and transmission of ADSB Out information in the US Congress in the last couple of days, do you think the NTSB could have confirmed (facts) how that information would have been displayed in the cockpit of the CRJ and the ATC TWR cab at Washington DC Reagan?

The small elephant in the room.

VHOED191006 , and others interested.

Dumbo Question 3

As you are no doubt aware TWR Visual Separation is a very powerful tool / method in the eyes of the controller or in the eyes of a delegated pilot. (Literally and metaphorically speaking, i.e pun intended.)

It is the very basis of ATC Aerodrome Control. Sophisticated use requires experience and excellent situational awareness.

I just wonder how many (if any) of the “reported” near collisions in the NTSB Preliminary report going back 4 and 14 years respectfully included perfectly safe visual separation?

The small elephant in the room.

ATCDumbo
I'm all ears, excellent point. This focus on ADSB-OUT, and ADSB-IN is really a furphy in terms of this investigation to determine the facts, the whole facts and nothing but the facts.

If 5342 had ADSB-IN then PAT25 not having or not displaying ADSB-OUT could be relevant depending on 5342's cockpit display, the training of the pilots and their scanning.
5342 didn't have ADSB-IN so move along, move along, nothing to see, these aren't the droids you're looking for.

**Caveat. If the TWR display were using ADS-B for their updates and to generate Collision Alerts then the absence of PAT25 ADSB-OUT could be relevant.
But would the TWR ATC even know (or care) whether PAT-25 was ADSB-OUT capable. TWR ATC involves looking out the windows and judging the relative positions of aircraft.

Note: ATC display systems are not referenced in the NTSB Aviation Investigation Preliminary Report. This seems to be a glaring omission. So perhaps the NTSB are either very dumb or deceitful or both.

To further illustrate the focus on ADSB. Figure 1 Google Earth image with preliminary ADS-B data for flight 5342 and radar data for PAT25.
The ADS-B plots are 1 seconds intervals, the radar data are 4 second interval (as stated during US Congress Q&A).
So the focus is on the whizz bang ADS-B kit rather than what the ATC saw on their display.

There is reference to ATC radios, and 5342 was on frequency 119.1 MHZ and PAT25 was on frequency 134.35 MHZ. The ATC could've had them on the same frequency (changed PAT25 to 119.1 MHZ) but this would be abnormal. ATC Voice Switch systems like Frequentis, SITTI and Rohde & Schwarz typically have a frequency coupling, whereby controller broadcasts on multiple frequencies (2 or more) and voice communications on one frequency are heard on the other. In this case, ATC would broadcast on 119.1 MHZ and 134.55 MHZ and 5342 would hear instructions for aircraft on 134.55 MHZ, and PAT25 would hear instructions for aircraft on 119.1 MHZ.

Yes, visual separation is typically used close to an aerodrome where the ATC is applying visual separation to reduce the standard from 3NM to something less, 2NM, 1NM, or even less, depending on the circumstance which includes weather (included visibility), day / night, workload to monitor the separation, plus other considerations such as equipment.

I just wonder how many of the January Route 4 Helicopter plots crossing RWY 33 Approach (post 1346) were the result of ATC issuing a control instruction to change the track to closer to the shoreline or further over water.

Use of Route 4 during RWY 33 Approaches or RWY 15 Departures is possible providing a clearance limit is imposed prior to assigning relevant traffic, positive control instruction(s) and in the case of 5342, advising them of the relative position of PAT25 and that PAT25 would be maintaining separation from them.

Example for Route 4 southbound would be a clearance limit of Hains Point. Helicopter would be released past this point when there is no conflict (nil traffic) or assigned separation to avoid (pass behind). If there is a in-line stream of arriving traffic then Route 4 may not be available.

Sydney KSA has something similar for one of their helicopter routes - BONDI 5 (yep, named after the beach), delays may occur when RWY 07 is in use for DEP, or RWY 25 is in use for ARR. Further, the route is not available when RWY 16 PRM approaches are being conducted. Sydney KSA helicopter routes are in text form - TRACK TO..., TRACK VIA..., EAST OF..., and the INBOUND routes to Sydney KSA have a clearance limit in the clearance. A map display is very useful however it should be based on route descriptions. Perhaps the committee of 17 knows the history of the helicopter routes in and around DCA.