Posts about: "TCAS (All)" [Posts: 152 Page: 6 of 8]¶

Unfortunately, and I hate to say this, I have reached a conclusion beyond those reached by other posters to this forum, to wit:
The US Army, in order to meet its mission requirements, really does not want civilian pilots (commercial or otherwise) to know where its helicopters are. My evidence for this is: The eagerness of the US Army pilots to assume responsibility for seeing and avoiding commercial aircraft; The DCA tower procedures that do not allow civilian fixed wing pilots to hear the conversations between the tower and the helicopters; The Army practice of turning off ADS-B out while on missions and training flights that follow mission profiles (as explained by the USA general in the hearing); The Army's refusal to produce the memo regarding its use of ADS-B to Senator Cruz.
Should the policies adopted by the US Army be regarded as the fundamental cause of this accident?

I'm applying SLF/attorney license here (hey, there's poetic license, so why not?) of repeating - with some editing - a post I placed on the R&N thread about testing at DCA.

1) Regarding ADSB-Out being turned off, what is the reason there was such emphasis placed on this at the recent Congressional hearing (and just scoring media points per usual in Committee hearings doesn't qualify as a "reason" in this context). Is the reason that there are objections to running the kinds of tests in question (per the R&N thread) in or near DCA airspace? Is it valid to say there is no connection to the chain of causes-and-effects which led to the midair collision on Janaury 29 (but if there is, what is that connection, specifically)? Is the reason some connection with the occurence of TA's and RA's on TCAS as documented by NTSB? (although other posts on the R&N thread indicate that ADSB-out isn't connected to TCAS advisories . . . that is, if I understood those other posts). Or something else? I'm dismissing the mere fact that FR24 doesn't provide information to enthusiasts as the reason for such emphasis in the hearing.

2) If the Army operates certain "missions" with ADSB-Out turned off, and it conducts these operations based on national security concerns, my initial thought about this practice is, . . . . . . . hey, isn't there a discretionary function involved in deciding what avionics (or electronics system if this isn't within the technical definition and scope of "avionics") to operate based on national security concerns? So the Senator declaring that there is "no justification" seems to deliberately overlook the existence in the Federal Tort Claims Act of the exception. (I realize there has not been, to my knowledge at least, any lawsuits filed yet. But they're certainly going to happen.)

Of course, this all said, the indictment of the structure and operation of the portion of the NAS in which DCA is situated might (as suggested previosly) itself be adjudged inconsistent and non-compliant with basic standards of aviation safety. The only not-crazy-sounding justification for that state of affairs would seem to be "but we have to move traffic in volume." As a legal wrangle over whether that obvious judgment of a "policy" nature is or is not a proper basis for keeping federal immunity in place in a particular matter . . . I am quite skeptical such a legal wrangle would ever make it as far as an actual courtroom proceeding. But will Congress not try to manuever itself into the issue for all the usual reasons - some people want actually to address the problem constructively, some just want to please their donors, and some just follow the crowd, or so it always appears.

3) Something about discovery in civil litigation was underscored by the exchange in the video clip: there's an Army memo, dated Aug. 9, 2024 as referenced by Sen. Cruz, about operating in the NAS with ADSB-Out turned off. And the Army so far declines to turn it over to the Committee. (Applying the rough equivalent of a pre-snap read by a QB, the manner in which the Army witness replied to Sen. Cruz's questions gave the impression that the Army and DoD will strongly resist the memo in question becoming public.)

[Okay, I'll refrain from speculating how much fun it would be to decide which officer or officers would be presented as the Person(s) Most Knowledgeable about the matters discussed in this memo (on the Army side, receiving the Rule 30(b)(6) deposition notice), or similarly, how much fun would be had by counsel describing the "subject matter(s)" which must be specifically iterated in a Rule 30(b)(6) deposition notice (on the plaintiffs' side).]

4. I'm very determinedly hoping this won't be read or even misinterpreted as an offensive point. In the YT video produced by "Mover" in which he interviewed a former Army helicopter aviator (post 1228), it was possible to draw the impression that Army helicopter pilots operating in the airspace in which DCA is situated have a certain attitude toward FAA ATC. That is, the Army operates - one could get the impression - in its own "airspace system" and deals with FAA ATC only as much and only as quickly as necessary. Listening to the pertient Jan. 29 ATC R/T, and knowing the visual difficulties presented by the basic facts of nighttime in that specific area of the DCA airspace, plus NVGs, an observer could get the impression that the Army aviator handling the R/T was doing so in a perfunctory manner on Jan. 29.

To explain further, upthread (in post 1261) in the context of a Mover/Gonky YT video (post 1228) someone much more knowledgeable than myself observed that the way in which the Army pilot interviewed in the video described communications with FAA ATCOs in DCA airspace was as if Army chopper pilots view FAA ATCOs somewhat as a nuisance. Far be it from me to fault any pilot over any practice or custom in anything, including comms with ATCOs. But faulting any pilot is not the point. The point is that in that YT video, as related that other poster, --
"it was suggested that it\x92s perfectly OK to second guess what ATC might have said to you, reply to that, and then if no correction is forthcoming you can comply with your guess. As others have pointed out implicitly, that works if there\x92s only one error involved, but here there were three: an untrue statement, leading to a wrongly issued clearance, and a missing read back."

It is known that ADSB-Out is not active on the Army and other certain missions in the relevant airspace. Is there also a pattern or practice of operating with a mindset that FAA ATC is a necessary nuisance, to be indulged but not focused upon as closely as other airspace users? If any reader asserts this question accuses the Army pilots or any one of them in the helicopter on January 29 of negligence - that would be incorrect. The way in which the airspace had been designed, managed and operated handed those pilots a pre-determined normalization of complacency - so it appears, does it not?. They operated their flight within the system they had been given, which does not constitute negligence. The designers, managers, and operators of that system . . . well, it will be for the courts to sort out whether the exception to the removal of federal immunity to tort claims applies to those systemic level actions, or not. If it were not for the existence of the discretionary function exception, I personally believe the race to the courthouse would already have been a feeding frenzy worthy of the most biting negative stereotypes about lawyers.

Speaking of immunities, wasn't it generally believed that the airspace within the NAS, and especially airspace in which major airports in the United States are situated, was immune to midair collisions, in general and not only collisions sudden, without actionable warning, and with at most two or three seconds' knowledge of impending death and disaster? Mere SLF/attorney as I am, I had believed that. It follows, but only under that mindset, that what occurred was obviously negligence, and even gross negligence. The point is, expect the lawsuits to be, in a word, consistent with the ugliness one feels seeing the wreckage pulled from the Potomac, or reading about the backgrounds of 67 people. Or both.

I tend to agree with ATC Watchers take on this.
Some people are making out that if the Helicopter had ADSB-out switched on/ activated, then this would never have happened.
Someone correct me if I am wrong but if the Blackhawk has ADSB-out switched on then nothing changes for the CRJ on that night. The TCAS behaves the same, there is no display of the Blackhawk on the CRJ\x92s Nav display\x85..nothing changes. The CRJ crew are still conducting an approach that requires a lot of fast mental processing close to the ground, at night onto a short runway while ensuring checklists/configuration etc is correct. ie they have a high workload. During this high workload phase, \x91the system\x92 has seen fit to allow a single Human ( the helicopter Captain) to be responsible for the separation of the two aircraft visually, at night, in a busy environment while conducting a check, on NVG\x92s.
Is it likey that a single Human, with the sole responsibility, will make a mistake? It\x92s not just likely, it\x92s inevitable, regardless of how sharp and well trained they are, if you run the program long enough their vision, or their SA will fail them and we get what we got here.
The system should never have devolved to the point where one person accepted the responsibility for visual sep 6nm away, at night, in a busy traffic environment while dealing with their own high workload.
The Blackhawk crew had a high workload, the CRJ crew had a high workload, the ATC had a high workload, there was no fat left in the system. Humans make mistakes and any good system will be tolerant of those mistakes.
The system was not tolerant of a mistake, ergo, the system is at fault.

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........

About those discussions at senior levels . . . If your reference to such discussions was meant to include not only within a given airline, but also some or all of the cadres of senior officials in the industry, U.S. government, international colleagues, and think tanks - those are the same discussions which are supposed to be going on now, in light of the NTSB's pro-active responses to the accident. Although it is a limited sample, in the accidents in which Board processes have been involved in the time I have been trying to keep up via PPRuNe and other information sources, I can't recall a similar "urgent recommendation" addressed to FAA as NTSB issued in this matter. Safety Alerts to Operators (SAFO's) yes, such as after Air Canada "There's no one on 2-8-Right but you" 759 in San Francisco in 2017. But not the same as what has issued from NTSB now. Perhaps I missed some salient details but the review which FAA became instructed and/or motivated to conduct would have a total NAS scope.

Or maybe such a review will, regrettably, require an Act of Congress (it should not require this, but, you know, K Street, campaign donors, the seniority system, and the generally stellar academic and career experience required prior to election to the Congress . . . . too bad elected represenatives are not required to build hours first).

I landed many times on 33 in a 727. It was not even considered difficult with a reasonable headwind which is why you would take 33 in the first place. Today with the children of the magenta line flying I suspect it might be considered a bit more challenging even though more modern aircraft with autothrust and excellent mapping it should make it even easier.
There is one point not mentioned in the thread. The two people with probably the best overall situational awareness of what was developing would have been the RJ crew. They received a traffic alert 18 seconds before the collision and the TCAS should have displayed the threat all the way to impact. I never allowed a threat inside a half a mile on a collision course even if they claimed they had me in sight unless I could visually see the threat. I got scolded by tower at DCA for going around once when we could not see VFR traffic tower said had us in sight. I didn\x92t care even though it was daylight. With a threat bearing down on TCAS you need to take action to mitigate the threat. Hoping they really have you in sight is not a good strategy.

(emphasis added)

After waiting a few days to find out whether replies would be posted by other knowledgeable aviators besides Sailvi767, and despite status as just SLF/attorney, I've got to ask: Is it a reasonable inference to draw from the quoted post, especially the part underlined, that the RJ crew perhaps was not completely without responsibility for the collision? I do not lightly (this has been batted about previously) even so much as imply responsibility for accidents on the part of pilots. Yet the quoted post seems to suggest that in this specific instance for the specific reasons stated, the RJ crew might have had a share of the responsibiity.

I admit I had thought of the RJ crew as having been not aware of any information suggesting or indicating immiment danger (despite having written an academic paper about Uberlingen a few years ago). And, the facts which potentially lead to assigning a share of responsibility to the RJ crew also would then change the contours and progression of the litigation, quite dramatically, and not only in terms of impact on familly members. Bringing in the airline as a defendant would direct the complaint drafter's mind to questions of the most effective style, organization and content to make the case for punitive damages. Forum readers following the legal aspects of the accident on the thread may recall that punitive damages are not recoverable in a tort claim brought against the United States Federal Government The airline company or companies here have no such protection.

Hiya WR 6-3 , the fact the RJ crew had a TA (IIR) has been mentioned/discussed a few times in this Thread - it's easy to forget!!! There is a problem with this tho.....

To briefly reiterate what has been said before, in such a complex airspace environment TA's (which is a step down from an RA, which requires mandatory action on the part of a crew, but RA's are inhibited by TCAS at that low level) can happen fairly frequently due to the proximity of adjacent aircraft which are not necessarily a threat - such as when helo traffic is close but is due to be avoiding you. You could get a TA and yet the helo will pass, say, just behind/below you - and all is well. If you recall, the number of TA's noted in the various Safety Databases has also been discussed and points to issues with 33 and R4 being fairly frequent - the warning bells re the 33/R4 airspace configuration had been ringing in the months/years leading up to this sad event - even if it had always ended OK ......... until this time.

The problem really comes when you regularly get such warnings; they become almost "normal". Normally, if you execute a go-around (not mandatory) against such traffic which ATC has specifically organised to miss you, ATC would rightly ask why plus, if you can't see it, you could go-around into it. Here the RJ crew were involved in the execution of the side-step on to 33 and were fully concentrating on rolling out on quite a short Final and would be expecting ATC to keep traffic away from them. So they would likely have noted the TA (I only use "likely" as I can't recall any facts on that) but now you have a highly split focus; flying the last bit of the approach where you have to monitor the PF/aircraft on the approach, ensure you remain stable to touchdown, keep a check that the a/c on 01 was not moving...... etc, etc and trying to see TA traffic - at low-level against a sea of lights. High workload, a belief/trust that ATC has you covered, and a rubbish environment to pick up the helo which is also not an uncommon event at DCA.................... Not a good hand of cards to hold at all.................. That's a polite way to put it!

So, this was definitely not a case of "Well, they had the traffic info so they should have avoided it!" - it's wayyyyyy more subtle and complex than that. That last bit of the cheese, if not having an actual hole in it, was so thin as to effectively be useless......... On your "legal culpability" point (where I have absolutely no quals!!!) I did mention, during discussions of the reports on the Safety Databases, that airlines and airports have a duty of care and so they could (should?) have been conducting Safety Audits which may have highlighted this Risk. Maybe they did and people picked the Risk up but continued to assess it as being "safe". Who knows..........................

That\x92s perhaps a VFR response and appropriate here, but you cannot deviate from a clearance on just TA. TCAS training since its adoption has been to not maneuver for a TA, only for an RA.

Hiya WR 6-3 , always worth discussing so no worries.

The baseline is that a TA on it's own is not enough and can even lead to issues if reacted to without knowing exactly where that contact is and what it is doing. You should, if you have the time (hence my comment re workload for the RJ crew at that point), try and get visual on the traffic but, tbh, it's very difficult to do, especially at low level at night against backlighting. You don't even really have time to "debate" a "shall we react (against SOP) to (yet another?) TCAS alert at DCA?" with all else that is going on at that point of a flight. SOP/Training says "fly on"! You need compelling evidence to go against that. I fact, IIR, the NTSB noted that the CRJ had full "up" elevator at the time of impact - that implies the crew finally saw the helo and reacted ..... but with no time to change their flight path.

If you want to "do" the airline - I feel a much better case could be made based on the fact the evidence of issues for that approach at DCA was sat in the Safety Databases for anyone who went looking, that maybe even crews had raised the issue themselves through internal reporting in the Airline, and/or there was no process in place within the Airline to review operations into DCA - or any other airport. This is promoted by the FAA who state that "The [airline] SMS promotes a defined structure and a \x93learning culture\x94 within an aviation organization that continually seeks and analyzes information, then turns that information into action that eliminates or mitigates safety risks, before they become unwanted events.". The full ref is here. And that also applies equally to the Metropolitan Washington Airports Authority who I believe operate DCA as an independent organisation. How the MWAA fit in to US Government - I'm not sure!

Anyway, hope this helps. Cheers, H 'n' H

As earlier mentioned, TAs (Tower and TCAS) may among other incidents and excursions find their way into databases including ASIAS. Once the NTSB dug into the databases, it came up with a long history of losses of separation at a frequency that makes one wonder that such an accident hadn't happened earlier. I suspect that this is not solely a DCA problem.

But who should be watching the data for trends - individual regionals, individual majors, local military, local ATC, individual airport authorities, FAA, NTSB?

I never received that training. You can as a pilot use your emergency authority to deviate from any clearance. Responding to a RA is mandatory. Responding to a traffic alert is up to the pilot flying. Yes they don’t want pilots routinely violating clearances for initial Traffic alerts. They want you to respond to the RA if it occurs. Many pilots do take action within their clearance to prevent a TA from becoming a RA. A simple change in rate of decent or climb can often accomplish that. Below 1000 feet knowing that RA’s are inhibited you are saying you would do nothing with a threat displayed on a collision course? What will your thought process be after the collision? Hey, that TCAS was right!
Keep in mind they were on a visual approach and that you can go around from any approach for any situation you deem unsafe. We will agree to disagree that a threat at the same altitude and constant bearing decreasing range displayed on the TCAS inside 3000 feet does not warrant crew action.

"Originally Posted by FullMetalJackass
If I get a traffic alert in my personal aircraft (I don't get RAs, just traffic warnings), I'm taking action to increase the altitude difference between me and the conflicting traffic. ."

Yes, we are trained to use TAs to find traffic, and RAs to avoid, but I think 767 is right about things being different when you know that you wont get an RA.

The NTSB specifically stated they will reconstruct the TCAS data onboard the RJ. It is possible even though they got a traffic alert that the TCAS target dropped off the display. This can happen for several reasons. I am however fairly sure they can reconstruct all of that. At some point there will be a full accounting.

Quick take after looking at ADS-B data and listening to some LiveATC:

DCA LC helicopter and fixed wing positions were combined (Bueller? Bueller?)

PAT23 was a Gold Top (Mike) UH-60

PAT23 was issued two holds along Route 5: (1st) 3 mi W of DCA, and (2nd) at \x93Glebe\x94

LC then cleared PAT23 from \x93Glebe\x94 along Route 5 to the Pentagon

LC made multiple requests to PAT23 to report landing assured. It seemed to take an unusually long time for PAT23 to get to the JPN landing pad. Unclear why PAT23 (and apparently other helicopters) fly counter-clockwise; i.e., continue to follow 395 S of Pentagon (past south parking), then turn N to follow 110 (past the Metro entrance) to the JPN landing pad. Why not use the charted transition route along 27/Washington Blvd?

LC seemed unclear of PAT23\x92s position. At one point directed PAT23 to fly westbound while PAT23 appeared to be landing.

Both DAL1671 and RPA5825 go-arounds were LC directed. No pilot reports of TCAS RA heard. After checking in with departure/approach, PCT didn\x92t request reason for go-around and pilots made no comment about go-around.

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.

Does anyone have a link to the TCAS simulation. That is of interest to me since I had a go around off runway 33 based on TCAS.

Is it MIT-LL TCAS-ACAS SIMULATION STUDY in this list?
#17

The TCAS display according to the video in the investigation docket did show the traffic all the way to impact. It was the last chance to avert this accident.

TCAS gave a TA just prior to that, why should TCAS have lost track?
That's why I don't understand all the fuzz about ADS-B in the UH60. TCAS in the CRJ worked as designed, including RA inhibit down low.
the CRJ crew getting a visual on the UH60 some seconds earlier could have saved them as well, one of many items on the 'could have saved them' list.


I've wondered a couple of times, what if.... the CRJ crew had failed to spot the UH60 all together. Now a left-banking evasive manoeuver was started, and only the left wing was substantially shredded by the rotor.
If they would has kept wings level, maybe both wings would have narrowly escaped major damage, only MLG and belly at risk of the main rotor.
But it all doesn't matter, really. 'Fate is the hunter' and they got caught.