Posts about: "TCAS (All)" [Posts: 152 Page: 5 of 8]¶

Hi Bill , understood, I was a bit too harsh maybe, but I get upset to continuously read what the controller should have done. Remember he was trained like this , to follow procedures that were basically unsafe in order to move the traffic . I can say unsafe because they were removed immediately after the accident , not waiting for the NTSB to recommend it . No everyone is stupid in the FAA , they knew this route was in conflict with 33 Visual arrivals. And did not pass any safety case, but the procedure was kept , most probably due political or military pressures , relying on controllers and pilots to mitigate the risks.

Now on the Conflict alert on the BRITE display . I have no first hand info on the SOPs in DCA on how a TWR controller uses the BRITE and if STCA are even displayed . `, but if they are, seen the charts and the routes , I guess STCA alerts are very common .especially when you delegate separation and you then play with a couple of hundred feet, vertical separation Too many unnecessary alerts equals normalization of deviance, . Look at the Haneda preliminary report , same ..

Finally since you mention TCAS RAs , there is a major difference with STCA , it is not the same as a TCAS RA . With an RA , as a pilot you have to react and follow , it is mandatory , for a controller a STCA is just an alert , just like a TCAS TA , if in your judgement it will pass you will not do anything , and if you have already issued a correcting instruction ( heading, level , etc,,) or here delegate visual separation , the STCA just becomes a nuisance. .

I sincerely hope the DC Controller will not be made the scapegoat of this accident . Not so sure it will not.

Concur. Scapegoating stochastically guarantees a repeat incident/accident of the same kind under "rhyming" circumstances.

Rarely does the "bad apple" theory of accident causation survive the scrutiny of a robust, honest investigation.

I am not a US controller but as I understand it their conflict alert is not a last minute save in the way TCAS is.

TCAS RA says that a collision is imminent (within the accuracy of the system, ie it probably means the system can\x92t prove the planes won\x92t hit).

Conflict alert is to notify the controller well in advance \x97 maybe a few minutes for en-route. It isn\x92t a loss of separation, it is so they can avoid a loss of separation (3 or 5 miles for radar).

I would say that TCAS is designed to issue guidance on a projected loss of separation, not necessarily an imminent collision (although it does that too). A highly simplistic explanation would be that it projects a nested set of egg-shaped volumes around the aircraft, which if it looks like they will be infringed can generate a TA or RA, depending on where the intruder is projected to make its closest approach. These volumes have nothing whatsoever to do with ATC separation standards.

The problem with conflict alerting is that in mixed-use airspace you will get a lot of warnings; I hesitate to say false as they are defined by preset parameters that may or may not be relevant to the potential conflict. Talking to controllers in the UK, they often turn this feature (STCA) off as GA traffic happily avoiding each other by visual and/or electronic means can fill the screen with so many alerts it distracts from the main job, especially if you are not in communication with either aircraft.

I would expect, given the traffic density around DCA, that CAs are so commonplace they have become unremarkable, indeed expected. Twice the controller was told that the traffic was in sight, so in their mind they are applying visual separation (no minima, just don\x92t collide). The takeaway has to be that IFR/VFR separation at night by visual means is inherently risky and so a questionable pursuit.

I agree that the DC controllers should not be scapegoated. At the same time, the concept of professionalism must be addressed. The concept that professionals in a field must alone (without management, without lawyers, without the public) maintain the best practices of the given professional discipline.

In the US, physicians who work for "Health Maintenance Organizations" are asked to practice medicine, at times, in a "basically unsafe" manner...to keep patients moving. On occasion, such practices will bite a patient (and sometimes the physician). As a whole, HMO physicians do not enjoy the best reputation.

From my perspective, there is practically no difference between the plight of an American air traffic controller and an American HMO physician. Both are expected to "squeeze one more in." Both fields are staffed by above-average capable individuals who thrive on challenges. Both are managed in such a manner that they cannot say "no" and also keep their job. In this regard, at least physicians have job portability.

But the take home point is that one cannot admit to knowing a practice is fundamentally unsafe, yet do it anyway. The public, rightfully, should not accept this. I have no solution except more staff and/or more airports (and not some next-gen whizzbang computer system).

Simplex RT works fine. We are all trained how to listen before using the PTT, how to formulate a transmission and how to allow space for an answer - most of the time.

ATC works very well. All efforts are made to avoid any confliction from the flight plan stage to the tactical stage - most of the time.

Pilots develop an awareness of other aircraft around them by listening to the RT, watching TCAS / Wx radar and looking out. This is most useful in understanding complicated situations - most of the time.

Even when the odd situation occurs where time and ideas run out and things are tight, people get away with it - most of the time.

But - not all the time. The Tenerife crash for instance involved a double transmission. One aircraft in extremis stuck on the foggy runway, trying desperately to stop the other rolling, while a tower communication took place and the RT was jammed. The question is, do we want to plan for these rare last second occurrences? I would guess yes - same philosophy as with GPWS and TCAS. We should have a means of communicating where an priority transmission overrides other radio traffic. There will be many who can explain why this can't be done, impossible, too expensive or unworkable. I am not here to explain in this modern and digital World how it should be done but you young bloods should suss out fairly quickly how it could be done. (spoiler - don't forget the open guard box)

Here you go. I feel rage too. And I'm willing to bet that those responsible are not held to account. You can hear the, "we've looked at this and there are definitely changes we can make to increase the safety in this airspace" being warmed up. I looked at the other heliroutes charts for the US around NY & Boston, and I can't see any minimum or maximum altitudes at all. I'm sure someone who knows these areas can point out what I'm missing. But if I'm not missing anything, then it's a sign that the bare minimum is put out there for guidance, and the people who are trying to make the best of it will be hung out to dry.

So the message for everyone is to politely and firmly refuse to do things that are not in your own interest, to make copious reports through safety management systems of events that you see that breach the normal, and to stop trying to work around a broken system where you ultimately will be the scapegoat.

No you can't , not in ICAO land anyway . Definition of " visual" for us is via eyeballs not an electronic display .,We always correct (mostly US)pilots which when passing traffic info reply to us " we have it on TCAS" . This is not a positive visual acquisition .

The last time I flew an aircraft with TCAS (a training aircraft) if we got a TCAS alert the point was to then find the traffic visually.
Did something change about this?

Yes that as the old way , the JAL/JAL encounter and Ueberlingen changed that to : forget visual acquisition just follow the RA, The traffic you see might not be the one giving the RA and even if you do the maneuver you might take will increase the risk , as in the 2 cases I mentioned.

In this scenario, there is zero information in the call to "pass behind" that indicates any imminent danger. All it does is further legitimise the previous two approvals for visual separation.
Now if the controller had said "you look to be tracking very close to the CRJ are you sure you can pass behind?" or similar, then maybe the helo crew would have got excited. A call like that might have even triggered a "holy sh1t" moment about the TCAS "Traffic". But as far as they were concerned, they knew they had the traffic in sight and could do the visual sep thing and even if they had heard "pass behind" they would have said/thought "well, obviously". Except they had the wrong aircraft. ATC had an idea they had the wrong aircraft but didn't get the message across.

As for the reference, same thing. The helo crew could have read-back "pass behind" but it wouldn't have achieved anything.

Yes, the RT added no more traffic information than before and completely failed to get the imminent danger across to the IP on the helicopter. However someone may have got a hint because there was a subsequent conversation between crew members about whether they should move further east. But we don’t know yet if that conversation was actually about traffic deconfliction. It could just be about accurate tracking of the left bank of the Potomac or something else entirely.

You should still attempt to acquire TCAS threats visually. The only change is that even if you believe you have the TCAS displayed target in sight you must follow all RA vertical speed requirements if TCAS generates a RA.

From NTSB interim report on DCA aircraft / helicopter collision.

"Near Midair Collision Events at DCA
Review of information gathered from voluntary safety reporting programs along with FAA data regarding encounters between helicopters and commercial aircraft near DCA from 2011 through 2024 indicated that a vast majority of the reported events occurred on approach to landing. Initial analysis found that at least one TCAS resolution advisory (RA) was triggered per month due to proximity to a helicopter. In over half of these instances, the helicopter may have been above the route altitude restriction. Two-thirds of the events occurred at night.

A review of commercial operations (instrument flight rules departures or arrivals) at DCA between October 2021 and December 2024 indicated a total of 944,179 operations. During that time, there were 15,214 occurrences between commercial airplanes and helicopters in which there was a lateral separation distance of less than 1 nm and vertical separation of less than 400 ft. There were 85 recorded events that involved a lateral separation less than 1,500 ft and vertical separation less than 200 ft."



What is seen - reported; and what is dismissed … diminishes the value of reporting.
A system broken: a broken safety management system at the national level.

Normalization of deviance?

It won't be the last time I'll think it compulsory to say this about this accident - I'm not trying to provoke the inevitable lawsuits into higher intensity (despite status as simple SLF/attorney).

Almost invariably lawyers as well as law students and professors, when asked to comment about what is taught in law school, recite the truism that "law school teaches you how to think like a lawyer." Problem is, even quite modest experience in and with the realities and pressures of representing clients - i.e., practicing law - dulls the thinking part and intensifies the hustler mentalities, of which there are many variations. I'm noting this because law school actually trains you how to spot the issues. It sometimes is the case that the standard things lawyers think about a given set of issues are not the most relevant and meaningful things.

With that hopefully not grossly pedantic context out of the way..... in previous comments on this thread I've noted that the federal defendants would be expected to assert sovereign immunity.... more technically, that although the Federal Tort Claims Act waives sovereign immunity in general terms, the statute also contains various exceptions - in other words, the exceptions where they apply keep sovereign immunity in place. The exception relevant here is the "discretionary function" exception, which (pardon the attempt at over-simplifying it) keeps the immunity in place if the allegedly negligent act (or omission) resulted from a federal entity's policy decision or choice.

I previously viewed the discretionary function exception is likely imposing a pretty strong barrier against liability of the (probable) federal defendants. However.

However. However, as I write this somewhere in an aviation law practice a mid-level or even junior associate is pounding their computer keyboard, amassing BASED ON THE ISSUES NOW REVEALED an analysis of how the discretionary function exception has never, never ever ever, been imposed to bar liability for alleged negligence roughly and/or reasonably comparable to the record of "encounters" now documented by NTSB Prelim Report. And that record goes back several years . . . but presumably discovery in United States District Court under the Federal Rules of Civil Procedure could easily reach back to even more past years.

Of course, it will be said that ignoring these many encounters was indeed a policy choice, and so the exception does apply, a forum post like this notwithstanding. But that's just the point. The ISSUE here is that there never was a conscious policy directive which the alleged negligence stemmed from. Or stated another way, if I were in the aviation practice imagined above, I'd be running associates ragged to amass the above-mentioned analysis which establishes, among other things, that GROSS NEGLIGENCE by the FAA can never be, and is not as a matter of law, a predicate for applying the discretionary function exception. (For lawyers out there, somewhat akin to prima facie tort.)

By the way, for all the discovery sports fans out there, just think how much fun it will be to run discovery to amass the facts of what actions - meaning by the aircraft in which the RAs were annunciated - were taken as a result of all the RAs as noted by NTSB's Prelim Report.

i believe it’s run by the MITRE Corp for the FAA. When I ran a corporate flight department, our FOQA data went in monthly, anonymously. I’ve gone into the ASIAS website for “meat” for safety briefings, etc. There’s a good pile of data including FOQA, unstable approaches, TCAS, CFIT near misses. Now who and how is the data used, I cannot say.

One example, after the KBED G IV accident, the NTSB went to the NBAA asking for help in better use of FOQA data increase compliance with flight control checks. Remember, this the G IV crew who tried to take-off with locked controls. ASIAS has tens of thousands of flight control checks and compliance data. Focused on that, measure it, problem mostly solved.

GE Digital’s FOQA programs also have a tremendous data bank. For example, KTEB has an easily the highest rate of TCAS encounters for corporate operators. How it compares to KDCA, I again cannot say. The airlines have the KDCA data for their operations. They know how many and where TCAS events occur. More evidence of normalization, I suppose.

I don't recall seeing this specific Blancolirio segment previously - and thank you AirScotia for putting it up here.

SLF/attorney as I am, I've looked up some information about ASIAS. Not to bury the lede, the legal issues about whether or not the entities within the federal government which are likely to become defendants in the inevitable litigation will be able to defend successfully on the basis of sovereign immunity will draw, and perhaps draw heavily, on information about ASIAS. This just is my view as (for lack of a better label) an observer, and I'm not part of any legal group or practice currently involved with the matters arising from the accident.

1) Juan overstated one point which could become significant in what I think is the impending legal wrangle over sovereign immunity. The Executive Board of the ASIAS isn't comprised of all the stakeholders shown in one of the slides in the video. The Exec. Board "has representation" from all or substantially all of the stakeholder groups. (Source: portal.asias.aero) Didn't find (or invest more time in looking for) the actual roster of members of that board.

2) skybrary.aero has an interesting page about ASIAS. It notes the involvement of Eurocontrol, ICAO, and Flight Safety Foundation and includes further information about the ASIAS purpose and functions.

3) Most of the slides Juan included in the video appear to have been taken from (or at least those slides appear identical to slides in) a 2007 deck on the Voluntary Information Sharing System Working Group. I won't include the individual's name (just being cautious) but the deck is attributed to the Director, FAA Aviation Safety Analytical Services Division AVP-200. (The slides are marked (in fine print - no irony intended) as "ASIAS Proprietary". Yes, and 67 people were killed in a midair collision in the airspace of our Nation's Capital, so, I'll keep my "fair use" arguments ready if necessary.)

The slides in this deck include a chronological look-back at the genesis and iterations of efforts leading up to ASIAS, from 1995-96 through 2007.

The slide displayed in the video which grabbed my attention was the one indicating that ASIAS is governed by formal principles. Why this is so interesting (imho) is that the legal issue of whether sovereign immunity does or does not apply to FAA and (though it is more complicated) to the Army depends on whether the "discretionary function exception" applies. (That is, a federal statute removes sovereign immunity for negligence in general, but it also includes exceptions where sovereign immunity remains in place as a defense . . . or an affirmative defense, but this isn't law school or actual representation). I'm not drilling into the potential arguments and counters at this time. That being said, I'm quite inclined to think that it will be difficult to prevail on an argument defending the way FAA continued to run DCA because that way was based on policy choices or judgments instead of defined rules - in other words, that FAA exercised discretion in a matter of judgment about policy issues. To reduce this to some absurdity, "show me the policy decision memo that was written about a choice between tolerating the risk, now revealed as obvious - and didn't Board Chair Homendy say it was "intolerable" - of midair collisions, instead of applying all the safety principles embedded in the very existence of ASIAS itself." I'm not waiting for such a memo to surface, but if it exists, surely it will be found in discovery.

4) Not least, Juan walks through some specific reports of previous aircraft-helicopter encounters at DCA. At about 8:50, no. 1458911, he relates an incident with chilling parallels to the fateful night of January 29. I mean, if our court and legal system in the United States still has any meaningful relationship to "the interests of justice" . . . this will be (imho) powerful and effective evidence. And it's not from a distant past - just 2015. If my notes are accurate, the incidents just after this one (a Captain who calls DCA the most dangerous airport he's familiar with or words to that effect), and the previous incident also (a TCAS RA, complied with, but then a GPWS from the tower was triggered, incident 1558721 at about 8:15) - when was a specific policy judgment made to shrug off incidents such as these, and what were the alternatives then considered? Or was it "system drift, this is the way we've always done things, National is close to the Hill you know" .... these explanations do not constitute policy, in my view, but rather negligence that can and should be held to adjudicated responsibility and accountability in the United States District Court.

One last point is that Juan's calling attention to the swift and unequivocal actions taken by the Secretary of Transportation is something everyone involved with aviation safety and operations ought to concur with. Not even a month in the role yet - and this tragic calamity occurs. Salute!, Mr. Secretary!

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.........

Disappointed to hear that. Searching for or expecting genuine emotion in the political theater of a congressional hearing is like searching for virtue in a brothel.

I also watched the hearing and learned little new from the parade of platitudes and witness obfuscation. I thought far too much time was spent on ADS-B (an acronym which Maria Cantwell is incapable of uttering correctly). No discussion on use of visual separation. There were a few new points:

1. Cause of spurious DCA TCAS alerts. ME links in related thread.
2. When NTSB examined other Blackhawks of 12th AB fleet, found significant number which did not transmit ADS-B even when ADS-B switched on. One helo (accident helo?) was found to have not transmitted ADS-B for past 700+ days.