CRJ Page: 17 of 19

aox
August 10, 2025, 06:10:00 GMT
permalink Post: 11936017

Quote:

Originally Posted by andihce

There have been a number of references above to the woefully inadequate vertical separation provided between helicopter Route 4 and the approach to Runway 33. Given altimeter errors (expected and maybe not so expected) in the helicopter, a helicopter flying high (and possibly offset sideways towards the end of Runway 33) and an aircraft maybe low on approach, there really wasn\x92t any guaranteed separation.

I strikes me that, from my layman\x92s point of view, that this is the primary and gaping hole (among numerous others) in the Swiss cheese here.

At the same time, I get the sense that no controller was ever going to allow a helicopter to pass directly under an approaching aircraft and challenge that limited clearance.

My question is, should this have been (or was it?) formalized as an ATC procedure? Because if this had been proceduralized, I find it hard to believe that just nighttime VFR separation would have been found acceptable in that environment. Rather I would think that lateral separation should have been actively managed by ATC.

For one thing, with the CRJ (or whatever aircraft) pilots making a late switch to 33, turning to line up with the runway, etc., they may not have had the bandwidth to scan for a possibly conflicting helicopter, if they could even have seen it from their cockpit. (IIRC from the inquiry, the NTSB will be investigating that last point.)

I don\x92t know how difficult it may have been for the helicopter to see the CRJ, but the simple fact is that they did not.

I wouldn't bother explaining it to laymen as a hole in cheese. In layman's terms it's the same as having two busy roads cross, and no traffic lights.

And to stick with motoring analogies, some of us are used to considering that at a junction another vehicle can be partly obscured by a pillar for one eye, and in the blind spot of our other eye, so we might move our head sideways to help check better. Some aircraft have more windscreen pillars (this helicopter has four) so the aircraft in a constant relative position - which is the one that is the collision risk - may stay behind a pillar unless we move our head.

Subjects ATC CRJ NTSB Route 4 Separation (ALL) VFR Vertical Separation

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ignorantAndroid
August 10, 2025, 06:48:00 GMT
permalink Post: 11936029

Quote:

Originally Posted by andihce

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."

Quote:

Originally Posted by andihce

For one thing, with the CRJ (or whatever aircraft) pilots making a late switch to 33, turning to line up with the runway, etc., they may not have had the bandwidth to scan for a possibly conflicting helicopter, if they could even have seen it from their cockpit. (IIRC from the inquiry, the NTSB will be investigating that last point.)

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

Subjects ATC Blackhawk (H-60) CRJ IFR NTSB Route 4 Separation (ALL) Traffic in Sight VFR Vertical Separation Visual Separation

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andihce
August 10, 2025, 07:10:00 GMT
permalink Post: 11936034

Quote:

Originally Posted by aox

I understand the point about constant relative position, but this "collision criterion" is generally stated for two objects maintaining constant relative velocity (constant course and speed) and heading.

The CRJ was executing a left turn for some distance up until the point of collision, while the helicopter was flying a fairly straight course. Under the actual conditions, the azimuth of the CRJ as viewed from the helicopter should have shifted significantly as the collision point was approached.

Subjects CRJ

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andihce
August 10, 2025, 07:27:00 GMT
permalink Post: 11936037

Quote:

Originally Posted by ignorantAndroid

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

Quote:

Originally Posted by ignorantAndroid

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

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.

Last edited by andihce; 10th August 2025 at 07:28 . Reason: Fixed quoting

Subjects ATC Blackhawk (H-60) CRJ IFR Separation (ALL) Traffic in Sight Visual Separation

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Sailvi767
August 10, 2025, 12:55:00 GMT
permalink Post: 11936208

Quote:

Originally Posted by andihce

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.

The CRJ crew was aware of the traffic. They received a Traffic alert from TCAS 18 seconds prior to impact.

Subjects ATC CRJ TCAS (All)

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Capn Bloggs
August 10, 2025, 13:27:00 GMT
permalink Post: 11936216

Quote:

Originally Posted by Sailvi767

The CRJ crew was aware of the traffic. They received a Traffic alert from TCAS 18 seconds prior to impact.

Depends how you define "aware". Clearly, they weren't "aware" enough to realise they were about to run into it until the last second. I must admit that, if I got a TA at less than 500ft on final at a controlled airport, I would have a good think about it before doing anything. It's night, they'd have to look at the TCAS return to see where it actually was, work out what it was doing, then start looking out. And guess what, just before they collided, the CRJ crew started pulling up, so they probably did all that and it took that long to react.

If your comment was intended to be a criticism, which I interpret it was, I think you're being unrealistic and unfair.

Subjects CRJ TCAS (All)

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BFSGrad
August 10, 2025, 22:26:00 GMT
permalink Post: 11936398

Quote:

Originally Posted by Stagformation

My understanding of Class B airspace is that all aircraft proceed only on the basis of an ATC clearance.

For most of its flight, PAT25 was operating outside Class B but in contact with PCT. At Cabin John with PAT25 operating right at the Class B floor of 1500 ft, the DCA LC approved PAT25’s request to proceed Route 1, Route 4, to DAA. That was PAT25’s clearance into Class B.

Two interesting events noted on the recordings:

At about 20:00L, PCT calls helicopter traffic to PAT25. I count at least 12 statements between the two pilots regarding the called traffic in addition to radio transmissions to PCT regarding the traffic. Contrast this to the CRJ called traffic which generates zero discussion between the PAT25 flight crew.

At about 20:37L, there’s a traffic interaction between MUSL13 and BLJK1 (two helicopters) that generates a conflict alert. The DCA LC provides multiple traffic alerts to both aircraft, including direction, range, and altitude of the conflicting aircraft, even after visual separation is approved for BLJK1. Contrast this with the accident sequence where PAT25 is provided with a single traffic alert and the CRJ gets bupkis.

Subjects ATC CRJ DCA PAT25 Route 4 Separation (ALL) Visual Separation

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WillowRun 6-3
August 10, 2025, 22:35:00 GMT
permalink Post: 11936401

Quote:

Originally Posted by Sailvi767

The CRJ crew was aware of the traffic. They received a Traffic alert from TCAS 18 seconds prior to impact.

Trying to understand how the individuals and organizations responsible for the operation of the DCA airspace and associated helicopter routes expected it all to operate safely. Also not exactly trying to anticipate lines of inquiry to be conducted by the Dep't of Transportation Inspector General, although I think Sailvi767's comment points to a key area that will be examined.

My understanding is that TCAS RA's are inhibited below some specified altitude, in order to reduce or minimize nuisance alerts. Is it a correct statement to say that when the CRJ received the TCAS TA's referenced by Sailvi767's comment, it already was below the altitude at which RA's were inhibited?

If that is correct, then doesn't it follow that the CRJ crew - intently focused on the approach to and landing on 33 - were following procedure that has long been acknowledged for DCA Rnwy 33 - the LC will keep helicopter traffic from becoming conflicting traffic? It is (I think, but only as a non-pilot and non-ATCO) obviously true that in this instance, there were a number of inputs (and lackof inputs) by ATC, and likewise several acts and omissions by PAT25 which led to the procedure failing badly, with the tragic result. In other words, the clearest root cause is the fact that the acknowledged procedure over a period of years was that the LC (and sometimes a helicopter position in the tower) would keep the helicopters from becoming conflicting traffic - and through normalizationi of deviance, when this procedure eventually failed, it failed all the way.

In a previous post I mentioned that one of the attorneys representing the families of accident vicitims has said that claims against the airline would be investigated and possibly included in the forthcoming lawsuits. I suppose it is not talking like a stark raving lunatic to point to the many reports filed about overly close encounters in the airspace, especially in light of information found and then released by NTSB soon after January 29 which detailed many close encounters (as a non-frivolous basis to assert claims against the airline). But wait. They are going to argue that, during the last few hundred feet on final approach to Runway 33 at night, after having been more or less directed by ATC to switch from Runway 1, running through all the steps outlined (by Capn Bloggs) to look for the possibly conflicting traffic took priority over flying the approach - especially in light of the long-acknowledged procedure at DCA? I'm admittedly shouting from down in the cheap seats but this attack by plaintiffs on the CRJ pilots, as an means to advance claims against the airline, strikes me as a legal obscenity.

Subjects ATC CRJ DCA NTSB PAT25 TCAS (All) TCAS RA

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ATC Watcher
August 10, 2025, 22:36:00 GMT
permalink Post: 11936403

Bit of confusion here . TCAS is not a separation tool , it is a last minute anti collision system . You are not obliged to monitor the screen, definitively not at 300ft on finals Not sure the CRJ crew noticed it . . Fact is the CRJ crew was not passed the traffic info . the reason why has been covered in the NTSB docket ( interview of the controller)
In class B , controllers will provide separation between IFR and VFR however they can delegate separation to an aircrfat visually following a strict procedure and phraseology .and issuing an ATC Instruction : " maintain visual separation "

Subjects ATC CRJ IFR NTSB NTSB Docket Phraseology (ATC) Separation (ALL) TCAS (All) VFR Visual Separation

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ATC Watcher
August 10, 2025, 22:45:00 GMT
permalink Post: 11936409

WR 6-3 : our posts crossed each other :
when you say :

Quote:

My understanding is that TCAS RA's are inhibited below some specified altitude, in order to reduce or minimize nuisance alerts.

Correct .

Quote:

Is it a correct statement to say that when the CRJ received the TCAS TA's referenced by Sailvi767's comment, it already was below the altitude at which RA's were inhibited?

Yes , but the CRJ did not receive one TA but 2 , one ( the PAT ) 200ft below , and the other 600 above , most probably the aircraft on finals for runway 1 . , it is quite normal to receive TAs on that kind of tight sequence scenario,. Finally a TA is not an RA. Pilots do not have to react on a TA. In fact some airlines Training programs specify that no horizontal maneuvers are to be made based solely on information shown on the TCAS traffic display. (TAs)

Last edited by ATC Watcher; 10th August 2025 at 23:14 . Reason: addition

Subjects CRJ TCAS (All) TCAS RA

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galaxy flyer
August 11, 2025, 00:26:00 GMT
permalink Post: 11936450

The minimum RA altitude is 900\x92 AGL, I think based on RADALT. They CRJ was below the RA envelope.

Subjects CRJ

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Sailvi767
August 11, 2025, 02:22:00 GMT
permalink Post: 11936469

Quote:

Originally Posted by galaxy flyer

The minimum RA altitude is 900\x92 AGL, I think based on RADALT. They CRJ was below the RA envelope.

Correct, they received an alert only to the traffic. RA would have been inhibited. The traffic then tracked in on the TCAS display to the collision. Some are posting that their company policy prohibits taking action. Watching an aircraft track in on a collision course and doing nothing takes a lot of courage. At my airline and most others what the policy means is that you should not deviate until you get a RA to avoid other issues or conflicts. When you know you are below the altitude a TA will function on final a go around is always acceptable for anything the PIC deems a potential safety hazard. Your airspace is protected. The policy deals with most other situations where you might create another hazard.

Subjects CRJ TCAS (All)

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ATC Watcher
August 11, 2025, 08:34:00 GMT
permalink Post: 11936560

@ Sailvi767 : Are you suggesting that somehow the CRJ crew bears some responsibility in not acting on a TA and therefore bears some responsibility in this accident ? At least this is what I am making of your posting .
If I am correct can you stop this discussion Remember journalists and possibly families members of those 2 pilots are watching too.
To close that bit just read the CRJ CVR transcript (*)
47:29 : eGPWS : 500 hundred
47:35 : I got 2 whites and 2 red
47:37 : cool ( my note : so they were looking at the PAPI )
47::40 : "Traffic traffic " ( my note : TA audio)
47:47 : TWR :" PAT 25 pass behind the CRJ "
47:55 : eGPWS : ...hundred ..
47:58 " Oh Sh!!!!!
47:59 : sound of impact .

Subjects CRJ Pass Behind Pass Behind (All) Pass Behind (PAT25)

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WillowRun 6-3
August 11, 2025, 11:33:00 GMT
permalink Post: 11936645

Quote:

Originally Posted by Capn Bloggs

Sailvi767, you're doing nothing more that Monday-morning quarterbacking. To say "yes, we're below 900ft so it won't give us a RA so let's get out of here" is totally unrealistic in these circumstances. Statements like " Watching an aircraft track in on a collision course and doing nothing takes a lot of courage." are just nonsense, in that, of course it would take a lot of courage and no-one in their right mind would do that in a normal situation, cruising along higher up. But these guys were 500ft off the water, at night, manoeuvring to a late-change final approach.

This. First of all.

Then second, Monday-morning quarterbacking, second-guessing, is one of media-saturated contemporary life's unfortunate and unpleasant irritants, and here is especially unwarranted. As one of this forum's usual suspects for legal aspects and issues, I will go further and say that even a thousand hours of Monday morning signal-calling will never, in this accident, show negligence of the two lost - senselessly lost - professional pilots.

The 1969 film "Z", directed by Costa-Gavras, depicts "a thinly fictionalized account of events surrounding the assassination of [a] democratic" European politician (from Wikipedia). The action centers on the work of a dedicated magistrate conducting the investigation. One hopes the DoT Inspector General staff will present such a dedicated person to examine how, for example, the helicopter route structure could have been thought to have been constructed safely. The film strikes this observer (I have no professional or otherwise occupational role in this accident) as relevant, inasmuch as "Z" was a slogan meaning, "He lives." A professional pilots forum could do worse for an overall attitude toward the CRJ pilots. . . . .Though with hope for a far more honorable epilogue to this investigation than occurs in the film.

Subjects CRJ

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Sailvi767
August 11, 2025, 17:19:00 GMT
permalink Post: 11936840

Quote:

Originally Posted by ATC Watcher

As I posted on here before I had that exact same scenario happen to me on runway 33 in DCA. Traffic closing on a collision course on TCAS. Tower reported the traffic had us in sight. When the traffic closed to \xbd mile with no vector change apparent We went around from 400 feet. We never saw the traffic. Tower chewed my butt saying the traffic had us in sight. I didn\x92t care.

Subjects ATC CRJ DCA Pass Behind Pass Behind (All) Pass Behind (PAT25) TCAS (All) Traffic in Sight

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Stagformation
August 12, 2025, 11:11:00 GMT
permalink Post: 11937189

Quote:

Originally Posted by ignorantAndroid

Obviously there's no way for a controller to know whether a pilot truly has the correct aircraft in sight.

Absolutely, but he does have the benefit of his own experience and common sense. Yes I accept that his experience may well have deviated to the \x91new normal\x92 at DCA over time, but common sense would still cast serious doubt on a report of visual on traffic that\x92s seven miles away at night, even using NVGs. The evidence suggests the LC did subsequently have his doubts, because he asked PAT again if he had the CRJ visual, since he wasn\x92t manoeuvring to maintain separation. Really a proactive revised clearance would have been more appropriate.

Last edited by Stagformation; 12th August 2025 at 19:11 .

Subjects ATC CRJ DCA Night Vision Goggles (NVG) Separation (ALL)

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Senior Controller
August 12, 2025, 11:45:00 GMT
permalink Post: 11937206

Quote:

Originally Posted by Stagformation

.... a proactive revised clearance would have been more appropriate,.

But he kind of did issue it : 20:47:42.0 TWR- (LC): " PAT two five pass behind the C-R-J " . [[i]sounds of rapid beeping consistent with conflict alert audible in background while tower is transmitting]
17 seconds before the collision , sadly he did not receive a clear readback on that instruction .

Subjects CRJ Pass Behind Pass Behind (All)

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Stagformation
August 12, 2025, 13:02:00 GMT
permalink Post: 11937250

Quote:

Originally Posted by Senior Controller

Yes he did, you\x92re right\x97 but it wasn\x92t proactive enough. Clearly the LC was conflicted, his eyes telling him PAT might not be visual, but the pilot saying he was. What an awful situation to be in. One which really needed a decisive move, not the easiest one, eg order a direct turn for PAT and/or a go around for the CRJ.

Subjects ATC CRJ Pass Behind Pass Behind (All)

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Musician
August 14, 2025, 08:04:00 GMT
permalink Post: 11938210

Quote:

Originally Posted by andihce

That would perhaps be a standard definition of "normalization of deviance". But I think there is a possible extension of that definition, which allows for the procedure to be flawed or open to interpretation, and considers "deviance" as departure from safe operation , even while the procedure is technically observed. It could also be the case that the procedure was initially valid, but became marginal as a result of changes in its area of application since its inception.

The procedure calls for the heli pilot to report "traffic in sight", which they did. The unsafe part is that likely they hadn't actually seen the traffic.

Quote:

In the present case (without knowing exactly what procedures were in effect), I could argue that permitting visual separation at night in this particular environment was a key procedural flaw. But it was accepted as there had been no accidents as a result, even as perhaps traffic density, etc. increased risk over time.

Visual separation at night is less of a problem if you follow the procedure as intended and don't report "traffic in sight" until you have correctly identified which traffic you're supposed to see.
We don't know if the heli crew thought they had seen that traffic (but picked the wrong one) or not, though the CVR conveys the impression they didn't, because they didn't talk about it (like they did about other traffic earlier in the flight).

It's also difficult to judge distance if all you see is a light, in your night vision goggles.
And it's especially difficult if you fail to predict the other aircraft's maneouver. The CRJ rolled out on final only 7 seconds before the collision. Until then, from a purely visual standpoint, everything would've looked fine. It required the heli crew to be aware of where the runway 33 extended centerline was (and where they were) to avoid being where the CRJ was going.

Subjects CRJ Separation (ALL) Traffic in Sight Visual Separation

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BFSGrad
August 14, 2025, 16:25:00 GMT
permalink Post: 11938451

Quote:

Originally Posted by Musician

Did DCA actually schedule conflicting flights without visual separation procedures?

Only the PSA CRJ was scheduled. The PAT flight was an ad hoc VFR Class B transition.

Note that the apparently informal procedure of holding helicopters at Hains Pt or golf balls was an effective method of deconflicting Route 4 and 15/33 traffic. However it appears that the use of this \x93procedure\x94 was left to the discretion of the individual controller.

Subjects ATC CRJ DCA Route 4 Separation (ALL) VFR Visual Separation

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Posts about: "CRJ" [Posts: 363 Page: 17 of 19]¶