Posts about: "Visual Separation" [Posts: 250 Page: 11 of 13]¶

I really value your contributions, as you bring an analytical and legalistic mind to bear, and help others understand some of the issues. However... from my (simplistic) viewpoint, the helo pilot explicitly requested visual separation. That's explicitly requesting the right? responsibilty? to keep themselves separated from other traffic. This they failed to do. Surely that is negligence.

There were other holes in the cheese, so the pilot was working in a compromised environment.

I'm just an SLF, so no domain expertise at all.

Let's say that the reasoning you have described is not only valid but also the dominant theme of an anticipated trial. Is it not difficult to contemplate a trial in which the central theory of liability is invoking a dread phrase, one with both the words "pilot" and "error", or at least the "negligence" version of that phrase. This would be a horrible case to see unfold. Of course the lawyers representing the families and other loved ones of the accident victims will press hard to make exactly such an unfolding happen - and their clients, the families and other loved ones, will be pressing just as hard as the families of the MAX accident victims are doing in the criminal case in federal court in Texas, if not harder.

This is not a reason either to dismiss, or to claim decisivenesss of, any particular legal reasoning here. It is instead recognition that reasoning which points to the request for visual separation and then the failure to maintain it as the basic cause of the accident will produce a very unpleasant legal case. Think of the Army units assigned to this sort of duty, how they are trained to treat "continuity of governement" and transport of highly important (presumably) officials as a kind of higher calling - at least that's the impression given by several statements or articles. And one set of their fellow servicemembers are put in the position of being blamed, and not present even to try to explain what happened. And that's in addition to usual strident reluctance to assign responsibility to aviators in situations where things go wrong.

Over the past several days, it has become clearer that the airspace environment was indeed so compromised that, as SLF/attorney without technical expertise or even knowledge about airspace design, management and operation, it would be best to stop trying to refine an understanding of the causes and effects and instead leave the puzzle-solving aside until the NTSB report is completed and released. That said, the way Sen. Cruz pressed witnesses last week suggests that waiting for the report will be a difficult task.

I appreciate any and every acknowledgement of efforts to make positive contributions to this forum - thank you for your post!

As other posts have admitted I am biased against assigning responsibility in situations such as this one to any aviator. There additionally may be a somewhat unique factor in this case too (involving some personal history about Army aviation maintenance training circa 1975, enlistment as an alternative to dead-end mindless jobs, and studying German in high school and for a couple of semesters in college so that if I ever went to Germany in the Army . . . ).

Hi layman54 , I think it's much more subtle than that. As you say, other bits of the system may put the pilots into danger but you then need to fully understand why the Pilot(s) didn't save the day. You sort of start off with the premise that the crew of PAT25 took off that evening and certainly didn't want to fly into the CRJ - so, why did they?

To say so-and-so got it wrong is often obvious ........ but why did they get it wrong? That's often very complex and can involve a lot more people and a raft of other factors and that's where the really valuable lessons are to be found. That's the real reason behind any "bias" - it's so we don't simply stop at that first person (or persons) who got something wrong, but look at what led to them doing what they did and what other factors contributed to the end result . That is the real way Safety is improved. You can then look at appropriate mitigation to try and prevent that same scenario from setting up another crew to fail in the same way at a later date.

As others have said, height and track is a red herring TBH as the deal with ATC was for PAT25 to "see and avoid" so they could have quite safely passed behind the CRJ at the same altitude or even above it - but not too close due to things like wake effects. If you can't manage "see and avoid" safely, you need to build in much, much bigger safety margins - such as holding PAT until the CRJ had landed. Many, including me, have asked how on earth the PAT25 crew (or, indeed, anyone) could reliably be expected to pick out the CRJ in that scenario especially at that range. For vertical/horizontal separation, relying on a few 10's of feet up/down or left/right is simply worthless given errors with altimeters and piloting accuracy in such a high-workload situation where it's "eye's out" navigating and looking for traffic all at a couple of hundred feet above land/water which is quite unforgiving if you get too low (I know ex helo crew who are no longer here because they inadvertently hit the sea) - not to mention any issues with NVGs (no idea, never used them!). What the NTSB implied was that, by suggesting that such a set-up as Route 4 passing under the approach to 33 was intrinsically safe through vertical/lateral separation, was madness. The route was pulled almost immediately pretty much on that basis.

So, for example, based on the difficulty in picking out the correct aircraft from the inbound stream, one of the many questions I've been asking myself is "Why were the PAT25 crew so willing to say they had the CRJ in sight (twice they said that) in that environment?". Had that become "normalised" on the Sqdn, or were the risks of miss-IDing a/c not being adequately highlighted in Local Orders, particularly given the geometry of that specific set-up? There may be several reasons - that's for the NTSB to dig out. I used to do a lot of visual separation stuff Commercially and I was nervous as hell - and that was in wayyyyyyyy simpler scenarios in way better conditions usually involving just one other aircraft. ATC were the same - they were very pointed in making sure I'd really seen the a/c in question. Any doubts in my mind or the ATCs mind and it was either an orbit till traffic was well clear or, if busier, it was "Contact Approach ....... lets chat again when they hand you back to me on the ILS.". OK, the ILS bit is not applicable to PAT25 but you get my drift!

There is no one reason why this accident happened - there will be quite a list with each one contributing to the final outcome. Any one of those things, had they been different decisions by those involved on the night, or, for example, by those who designed and approved Route 4 way back when, would have saved the day. So correct not just the 1st issue you find, find out and correct ALL the issues! That's what we really need to do to stop similar things happening again, not just at DCA, but anywhere.

Anyway, hope the above helps with the context of the word "bias". It was not that long ago it was "Hang the crew! Erm, oh no! Someone else has done it now! Hang them too!" Rinse & repeat! Thankfully, we are much better at digging out all the issues these days. But we have to constantly remind ourselves to "Look for everything, not just the 1st thing you find!". Cheers, H 'n' H

This raises the question of what fraction of helicopter crews in that situation asked for visual separation. And how often did ATC grant it? According to posts above sometimes helicopters were held at Hains Point so apparently visual separation wasn't universal.

Yep, that question .......... and loads more.

One thing I mentioned earlier is that airlines also have a responsibility for conducting safe operations; safe for their crews, their pax and by-standers. For eg, airlines often have additional rules for certain airfields (eg some require specialist training before crews can operate in there due to say, terrain issues on the approach). As has anecdotally been reported on here, if there have been an above "average" (and someone will need to figure out exactly what that means) number of issues with this particular approach in terms of TA's, irrespective of the outcomes, then the airline has a Duty of Care to have a system which identifies such issues, assesses them and then, if necessary, to put additional mitigation in place - such as, say, banning the use of 33. AA may have looked at this and, if so, their Safety Case should explain why they concluded it was safe. Sadly, even that doesn't guarantee the right decision was reached ...... but at least they'll have formally assessed it. Trouble is, landing on 33 seems to have cut taxi time = fuel = $'s.......

Anyway, just some thoughts! You know, I can be a right cynic at times but, having a background in Safety Engineering in a previous life, that's par for the course!!! Cheers, H 'n' H

I refer to the case of Lufthansa identifying night visual separation as a safety issue and deciding not to allow it, then one of their aircraft having to divert from SFO because of this decision. AA banning DCA 33 might have had the same kind of result.

Anyway, after 72 pages it seems fairly clear that separating IFR from VFR at night by visual means inside the circuit pattern of a major airport is not a great plan. This could happen anywhere in the US and it would be an interesting exercise for the NTSB/FAA to see how many separation losses there were at other airports, as they have the software to do that. It is easy to fixate on this accident and the immediate environment when similar setups exist all over the place. It\x92s not just about helicopters and the military - civil and fixed wing on that kind of clearance could be just as risk-bearing.

Who knows, you may be right. I think AA rocking up at DCA and stating that, as "policy", they'd never ever use the sidestep to 33 due to their own safety assessment flagging it up, esp if based on TCAS evidence, would have led to interesting discussions at senior levels. As you say, how that would have ended is anyone's guess. Bit academic anyway as there was no AA ban and the AA flight accepted it when offered it and the next AA asked for it on initial contact ..... not realising what had just happened! That's why I had a $ sign in my earlier post! The cynic that I am........

Apart from the IMC non-issue, the cause-and-effect chain of events and omissions in this accident is still under investigation. But I'll try to give some answer to your post - although I doubt my mind will latch onto anything new compared to the volume of this thread to date.

There are unknowns at this point about what information the Army PAT25 crew had in front of them about the altitude at which they were operating. There also are unknowns about the Army crew's visual scan (which, as a non-aviator, sounds to me like a complex subset of facts; I do work on maintaining strong visual scan plying limited access highways and even local streets and roads in my car but the instrument panel of my vehicle is, shall we say, somewhat limited in comparison). Add in the relatively fixed attributes of the physical environment, the background lights of the city and surrounding areas, the river, and so forth. Plus, NVGs, plus experience using same by the particular crew.

Then with all those factual matters still subject to fairly significant unknowns (at least as I am able to follow the developments), your question(s) turn to the acts or omissions of ATC. I am fairly strongly inclined to "stay in my lane" - meaning, there is a lot more about how ATC functions are performed that I don't know, compared to what I might actually have picked up from forum threads and other sources. It stands to reason that the visual separation set-up is subject to formal written rules and procedures, but I don't know to what extent these presumed rules and procedures reach down to very specific operational details. Beyond that, the signal-to-noise ratio of what more I might say would not be too especially good.

I'm reminded of the old saw that some one or another fairly well-versed individual has already forgotten more about a given subject than some smart-aleck will ever be able to master about such subject. I don't want to trip over that . . . altitude restriction.

One other perhaps non-trivial item I can add is that the attorney whose office has filed the preliminary claim (as required pursuant to the federal statute) is very accomplished in this field. I've met him at professional (Aviation Law) conferences. I have enough respect for other members of the bar who have amassed vastly larger public records of accomplishment - even those records which prompt lawyer-bashers to decry the profession and all who practice in it - not to try to pass off forum talk as the equivalent, or even merely reflective of, the serious legal thinking going on in that attorney's conference room. And many other law firm conference rooms. The issues in this matter aren't going to be simple, neat, or pleasant. Perhaps the air has been deflated out of the emotional shock-balloon the midair collision visited upon many folks; it is still my view that this was a catastrophe, wrenching in many respects the NAS all the way back to the skies over New York City in 1960 and the midair which ultimately gave rise to the formation of PATCO. And the strike, which led to, with respect to controller staffing . . . . .

The IP radioed "traffic in sight" which clearly showed that they had the wrong plane, if any in sight and lost both situational awareness. If have no idea why the helicopter had not its ADSB turned on. Training for real sneaking at night through DCA is idiotic as we know now with 20/20 hindsight. Visual separation with several planes in the area is challenging in daylight, let alone at night. You easy miss one.

What do you mean by " they were not aware of the traffic coming into 33 "? They were specifically informed about the incoming traffic circling into 33.
And they acknowledged it, although in a very short reply (understandable to keep R/T's as short as possible).

But replying with " traffic circling 33 in sight " just might have improved their own SA, helping to build the mental picture that mentioned traffic was going to move slightly to their left and was at some point going to cross their route from left to right. And if they didn't have that mental picture of what "circling 33" meant for their routing, then a lot was wrong long before the impact. Edit: UH60 CVR transcript of the same (notice the difference in transcript 'circling' <-> 'for') and yes of course, we all know, beaten to death, etc. that they 'locked' onto the wrong traffic for their visual separation in this very challenging and complex visual situation (not to mention at night with NVG's !!!).


And what strikes me over and over again, is this mutual 'pavlovian' "request visual separation"-"approved" thing, as if proclaiming these words, absolves all involved from any rules/restriction that might hinder the smooth flow of things (which it does - kind of).
Even at the last chance of averting disaster by the controller (by clearly indicating the target), the pavlovian reaction was there again (totally meaningless as it was already requested and approved 96 second earlier)... ... even while not catching the drift of the controller's last R/T (but hey, we said the magic words, so lets keep on moving)

I\x92ve been listening to the NTSB hearings while doing other things last couple of days. All I can say is the FAA testimony is wild .

Normalisation of deviance doesn\x92t even come close.

- Airspace design. The heli route stepping down to 200ft max lead some army pilots to believe it gave clearance from DCA traffic. Spoiler. It did not.
- Controller workload \x93Just make it work\x94 was a common attitude at DCA
- FAA not actively tracking TCAS RA \x93incidents\x94 as it could skew data.. maybe it was correctly applied visual separation etc. Need to look at the background etc. Yeah. But it generated an RA 🤬
- FAA refusing requests for traffic \x93hot spots\x94 on low level VFR charts as \x93hot spots\x94 are on ground charts only.
- PAT25 wanted visual separation from the CRJ. ATC was required to inform the CRJ crew another aircraft was applying visual separation to them. They didn\x92t.

Honestly from a European perspective. It\x92s quite bone chilling.

I feel this was a systemic failure. Airspace design and Risk Normalisation.

And my heartfelt condolences for the pilots, of both aircraft, and everyone else involved including the ATCOs. Not that there weren\x92t issues\x85 but in the Swiss cheese model, the FAA bought the cheese, drilled holes in it, and invited everyone to take a look inside.

Slightly surprised by some NTSB comments as well\x85 they were presented that the heli was straight ahead on the CRJ TCAS simulation presentation. But in actual fact the CRJ was circling in a left turn for runway 33. It was stable at 500ft but in a left turn to line up with the runway\x85 wings level at 300ft. It was challenged by the airline/ALPA but I would hope the NTSB would have picked up on that.

Low point of the whole hearing was Jennifer Homendy halting proceedings and moving witnesses to different seats, as one of the FAA managers elbowed a colleague while she was giving testimony - at which point she went quiet. Infernce being she was being reminded to stop talking.

Because, due to the proximity of Route 4 to runway 1 traffic, 12th AB pilots much more frequently received traffic calls for runway 1 traffic coupled with visual separation, traffic for which there would never be a collision threat. And if there was 33 landing traffic, ATC would just issue a hold. I\x92m still reading through the interviews, but have yet to find an example of a 12th AB pilot that, while on Route 4 with visual separation for 33 landing traffic, actually had to track the aircraft and maneuver to avoid.

In this interview at pages 97 and 112 the pilot says he has operated south on Route 4, and with traffic circling to 33, both accepted \x91hold at Haines Point\x92 and also accepted \x91visual, pass behind\x92 clearances literally dozens of times. Admittedly he wasn\x92t 12th AB. (This is a PSA line check captain who was formerly military UH-1N helicopter pilot operating in the area with USAF at Andrews AFB). Very interesting interview.

https://data.ntsb.gov/Docket/Documen...dacted-Rel.pdf

How would the helicopter pilot know they had the CORRECT traffic in sight? It almost seems like the were looking at another aircraft. Can visual separation be successfully applied in such a busy night sky?

That is ultimately the call of the crew. ATC only gives the option, it's the PICs responsibility to assess whether it is feasible and safe. I don't personally know any ATCo who would be comfortable offering that in this particular scenario, but that's coming from the European perspective where we have nothing even close to the proximity of military/civilian mixed traffic. I only did a little approach familiarization and no tower work, but just talking to colleagues who did, I don't think I'd be comfortable to offer visual separation in that environment. But then again threat normalization is a pretty effective thing.

Just went ,very selectively of course, through the thousand of pages of to the dockets and they give a clearer picture , to me at least . of the huge normalization of deviance that took place from both the DCA control staff and the RAT pilots.. I went mainly thought the interviews and the TCAS dockets.
What I learned:
Interestingly the Local controller involved was also a CPL pilot
Pressure to use 33 for landing during high departure rates was there to avoid the queue blocking the taxi ways for arriving aircraft : ( my comment : when you get to that situation traffic should be reduced by departure slots , that what we do in Europe with the Network manager CTOTs..)
No reaction to Conflict alert because visual acquisition was prioritized , i.e if you saw the helicopter passing behind you disregarded the CA. and this was almost always the case so CA with helicopters became disregarded
Advanced training was poor or non existent ( e.g Threat/Error management training).
On the PAT pilots interviews the most flagrant normalization of deviance is requesting visual separation with an aircraft you do not see ( yet) I realize that was declared by pilots other that the one operating that flight , but gives a good indication of the local " best practices " in that area.
Finally on the TCAS issue, one of the screenshots shows other traffic, and we can see that there were 2 TAs one in front -2 and one behind +6 , that could ( emphasis on could) have been one of the reason the CRJ crew missed the urgency of the -2 , but also probably were more focusing on the PAPI so both looking outside instead of at the display .

And to reply to a question earlier by DIBO on the discussion about ADS-B out not avail on the RAT, and its relevance for TCAS, well it would have influenced the degree of accuracy of the Tau calculation ( with Alt returns every 25 ft instead of 100 feet) and could ( again emphasis on could) have changed the alert logic/timing of the TA. Non installation of ADS-B and flying 70 ft too high are probably one of the points the lawyers are going to get into to prove negligence from the military to get more money for their clients , possibly shadowing the real causes. ; which for me are still the design of the procedure and routes, and the failure of the Regulator to act on the alerts. . Love to hear Willow-Run 6-3 comment on this .
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Absolutely, but the other side of the normalisation of unsafe practices coin is Local Controllers conveniently believing that pilots have instantly picked up distant traffic visually and granting their request!

I appreciate the invitation to comment. With first acknowledging there are several technical factors involved here as to which I have limited understanding (and also that I've commented several times on legal issues likely to be presented by the accident regardless), the legal picture probably is best understood if it is described in two contexts. The fact that the most clearly responsible entities - the Army and the FAA - are both parts of the federal government means that sovereign immunity must be taken into account. (Sikorski, mentioned as a potential defendant by one of the attorneys involved in the case already, has no significant legal risk here, in my view. The reason is its protection by a judicial doctrine known as the "military contractor defense." The specifications given to Sikorski for its design and manufacture were reasonably precise and it met them. See Boyle v. United Technologies Corp. (1989), if more depth and detail is desired.)

As for the airline, to fault the pilots when they were on short finals and expected to concentrate on flying - as others have expressed here numerous times - seems very ill-founded. Whether the airline company could be alleged to have responsibility for not having spoken up more effectively to cause the airspace design and procedure to be redone also strikes me as far too oblivious to the actual operation of the NAS, and the FAA and Congressional processes, to have any validity as an approach to liability. The airline and even Sikorski could still be named as defendants but, to reiterate, this would be just for leverage and not because there is any real pathway to liability for either one.

That having been set as background, the first context ignores the existence of sovereign immunity issues and looks just at what happened and who was responsible. As a rubric for this, "normalization of deviance" seems very accurate. This includes the fact that over time, ignoring Conflict Alerts came to be routine. It includes the practice of confirming "traffic in sight" or related proper terminology, for visual separation even though no traffic had been sighted yet - because it had become routine that the traffic would come into view and be properly identified as the traffic ATC had called out. The testimony about "just make it work", as I heard it, similarly was very concerning; iirc an overall very credible FAA witness acknowledged that the "just make it work" attitude also resulted in decreased safety margins. As did the medical helicopter operator who also had Army helicopter service background. Add in the lack of advanced training, and though I have not practiced law as legal counsel for accident victims' families, the liability theories here appear strong.

Then factor in the use of 3-3 to allievate congestion from high departure rates, rather than slowing or reducing departure slots. Part of the pressure to use 3-3 (as I understood the testimony) was that the Potomac Tracon wanted to increase in-trail separation but DCA instead increased use of 3-3. This was consistent with the attitude, "just make it work".

As to ADS-B on the helicopters, my understanding is that given the roles and missions of the helicopter operations, ADS-B is not equippage the military and its civilian control (in the sense of oversight) could have approved consistent with those roles and missions generally, and especially the continuing-of-government function.

Putting all the causal factors together into a "theory of the case" is perhaps better left to advocates for the accident victims' families (just as defense theories better left to defense counsel in this matter). But since you've impliedly asked, I would not - in this first context - parse out three of the four factors you noted, the lack of ADS-B being the one left out. That leaves the helicopter operating approximately 70 feet too high, the airspace design and procedures including the helicopter routes, and the inaction following the several safety alerts in databases and other reporting functions prior to the occurence of the accident. And including the forced enlistment of DCA for handling more traffic than the widely accepted airspace utilization and safe operation rules and procedures would allow - but they "just made it work." In other words, all of these three factors combine into the most likely theory of liability.

There is a second context, however. Federal government defendants are protected, despite the broad removal (waiver) of sovereign immunity by federal statute, from liability if the alleged negligence resulted from the exercise of discretion. If the actions or omissions being challenged resulted from decisions in which the federal entity weighed economic, social, political and other factors against each other in a form of "policy" decision-making, sovereign immunity remains in place. You can see where this is leading, of course. At what point does the over-use of DCA move out of the protection of "discretionary functions and decision-making" and into the realm of ... just plain negiligence which needs to be addressed in a court action. And likewise, at what point does the Army's set of decisions about how the routes are flown, and how visual separation and traffic sightings are handled, move out of the protection given by discretionary decisions and into the realm of significant negligence not deserving of such protection? Same question for FAA - surely the presence of safety concerns in databases and reporting systems - as unorganized as they may be and as lacking in systematic review as they may be - are matters within the FAA's discretionary functions and decision-making . . . until they're not. (And not equipping PAT helicopters or other D.C.-based Very Important air transport operations by helicopter with ADS-B would have no chance of being ruled not resulting from a discretionary function and decision - it's not even arguable imo.)

I almost included with this (already lengthy) post the "syllabus" of the U.S. Supreme Court's decision in the United States v. Varig Airlines case, which I think is the most pertinent aviation case in which the discretionary function rule is fundamentally involved....but this isn't a legal forum. Still, the U.S. S. Ct. opinion (467 U.S. 797 1984) gives me uncertainty about how any court of competent jurisdiction will draw the line between what would in a case against a not-federal defendant definitely appear to be negligence, and the actions and omissions of the federal defendants here. (My personal view is that the federal defendants acted with such severe negligence that the discretionary function protection has been lost - but that is a gut reaction to the "this accident never should have happened" idea and not legal analysis.)

Finally and last for a reason, I am not commenting about the motives of legal counsel who are representing or advising clients involved in this matter. I have not practiced law a single day, or a single billable hour, or otherwise, on behalf of the families or representatives of aviation accident victims, or the defendants in such matters. As a result, in participation as a guest on this forum I think it's much wiser to let the members of the bar who do have clients and who do practice in this area let their conduct in their professional capacities speak for itself.

It's simple; the altitude restriction was never intended to be the sole method of separation. At most, it was an additional layer of protection. The controller wouldn't have cleared the Blackhawk to continue if they hadn't said they had the traffic in sight. But they did say that, whether it was true or not. ATC is a service provided to pilots, not an authority. Pilot-applied visual separation essentially overrides any procedure used by ATC. When you say "Traffic in sight," you are saying "I don't need your help maintaining separation, I have it under control and I take full responsibility."

The IFR aircraft wouldn't be required to have the traffic in sight.

And yet as we saw, this approach failed. So something has to be wrong with it.

Yet was not the controller required to inform the CRJ of the helicopter, which (as the inquiry noted) he failed to do? Thus a possible cross-check was lost.