Posts about: "PAT25" [Posts: 116 Page: 5 of 6]¶

Sad to see the NTSB reporting PAT25 was between 278" and 313' in the seconds before the collision instead of 'at or below' 200' OK, PAT25 seems to attract much of the blame for the impact, but that doesn't detract from the unsuitability of Route 4 in the broader sense.

The route doesn't provide safe clearance, is the answer. Even if they didn't collide, I can't imagine the ride being particularly gentle after something that size passes ~50ft overhead. Even the near miss might have resulted in a critical loss of control.

The point is that PAT25 could have been tightly hugging the eastern bank at precisely 200 feet, and yet everyone would still have died if the CRJ had been slightly below its proper approach path (as it might easily have been). Yes, you can say that *this* accident wouldn't have happened if the helo had been at 200 feet, but that gets us precisely nowhere in preventing recurrence.

Systems that rely on human perfection are 100% guaranteed to fail. The only question is how often. The system in place at DCA required helo pilots to assume responsibility for visual (*not vertical*) avoidance of collisions in order to fulfil their ordered missions. Given what we know about human visual performance at night, that would eventually end badly, and sure enough it did. There is a strong element of the pilots having been set up to fail, which is why no-one here is going hard on them.

Altimetry and height keeping would be important matters for investigators if the collision had occurred due to a breakdown in vertical separation, which as a minimum would involve 500 feet (and more often 1000 feet) of planned spacing to account for instrument and height keeping errors. FAA instrument rating standards require pilots to be able to maintain altitude plus or minus 100 feet. This helicopter was being flown VFR at very low height, which means that looking outside takes primacy over monitoring instruments. I'm sure helo pilots could fly along at 175ft plus or minus 25ft if they really tried, but you can be certain they wouldn't be looking out for traffic (as is required when holding responsibility for visual separation).

However, as there was no vertical separation built into this procedure, all of this is at best a distraction. The more important questions are why procedural barriers were not in place to stop the route being used during landings on runway 33, and whether visual separation at night is an adequate barrier to collision when airliners and their human cargo are involved.

N123, join the downwind, your traffic is a 737 on final 2 miles out, turn base behind him, you are #2. I can do that at night unless there are other 737s lined up and then I have to figure out which one.
N123, do you see the closest plane lined up, pass right below and behind him and never mind all the other planes right behind. Ah......NO.
There is night visual and there is night nutty visual. The first example leaves a lot of room for error and time for ATC to see if it is going wrong.

So was PAT25 off track ? Not that it matters a great deal.

No, it does not matter much as he was performing a visual separation ,and remember, he was instructed to pass behind so it may deviate from track. ( although they might have missed this instruction according the CVR )

Did you take QNH into account ? Ads-B gives pressure altitude

Interesting to note that, had PAT25 been at 200 ft and the CRJ just slightly below nominal glideslope, they would have collided too.

And that, had the CRJ been on the glide slope, it would have been way below PAT25 and would not have collided

LC says, “PAT25, do you have the CRJ in sight?”

PAT25 says (for the second time), “Traffic visual, request visual separation”,
which is not true, evidently they were not visual at all because they crashed into the CRJ.

LC responds, “Visual separation approved, [pass behind the] CRJ,”
which clearance was issued on the false premise that PAT25 was visual. But PAT 25 only hears, “Visual separation approved…[pause]…CRJ,” because they briefly stepped on the LC’s transmission themselves. No read back is forthcoming; the LC should be expecting one but he fails to chase it up, because he’s too busy.

If PAT 25 realised he’s stepped on the middle part of the LC’s transmission to himself (which likely could have included an instruction) then he ought to be professional enough to say, “Stepped on, say again,” etc and make absolutely sure he knows what the clearance may have been. That was standard practice a long time ago, but no longer, it seems.

My original point was that in the Mover/Gonky video (post #1228) it was suggested that it’s 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’s only one error involved, but here there were three: an untrue statement, leading to a wrongly issued clearance, and a missing read back.

System broken.

pretty sure I was the circled aircraft that night, AA1855 from CLT. We were just about to be cleared onto the MTV1 when it happened. Did not see it happen but pretty sure we heard JIA5342 being handed off to tower. We were then vectored off the approach and eventually diverted to IAD. Tragic night.

Good points, especially the first, Keep in mind that no readback was required, and that type of instruction doesn't require a readback and according to the AIM is not even a type that "should" be read back, so the controller wouldn't be surprised if he didn't get one. Agree with Capn Bloggs;even if PAT25 didn't get the particular "pass behind" transmission, visual separation, which came up twice, carries the implicit instruction "Don't hit the other aircraft" ( no sarcasm intended), regardless of the method employed.

NTSB Aviation Investigation Preliminary Report - N709PS, PAT25

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.

Hiya WR 6-3 , firstly, please do accept my apologies if I came over a bit harshly re ASIAS. I always read you input as, while the detailed legal nitty-gritty is generally way beyond me, you always provide a refreshing viewpoint which is good to read! The aim of my Post, based on my interpretation of the above quote, was just to emphasise the existence of ASIAS is just as a tool or, rather, a set of tools but which has no real "proactive function" in itself. Yes, it represents a very small part of the Flight Safety chain - but as a resource in the main. As you say, there were loads of examples of what happened at DCA and my post was an explanation as to who, I believe, should have been looking at it. Maybe they did - and just ignored it? No idea!

In the UK, the airport operator is totally responsible for the safety of operations on or above their field out to 4000 ft on approach and departure - about 12 miles. The CAA who regulates aviation here, along with the Dept of Transport, but in conjunction with other stakeholders such as NATS (our en-route ATC organsiation), airlines and airfield operators etc, designs the airspace and sets the generic rules for it's use. As you said, the main rule is "Don't crash anything into anything else!". However, at the airfield, it is the airport operator who needs to ensure that the generic rules work in their environment. If a particular rule is legal but, if applied in their location, is unsafe, they can't apply that rule! That's what the Safety Case should say.

A relevant example? I used to regularly (for work) transit London S > N and N > S along the red dotted line below - at 2400ft as it kept me just out of the London TMA but as high as possible so, if it had all gone quiet on the engine front, I'd have the best chance to get the plane onto the ground with me alive and no-one else hurt. As part of the transit, I had to cross the final approach into London City (green line). So, say heading N, I'd chat to Thames Radar while over South London and would ask for a London City crossing. They'd chat to City ATC to co-ordinate and take me to the Thames before handing me to City Tower. My route over the Approach has aircraft at 1200 ft descending on the ILS and so I would have crossed anything landing at 1200 ft above that. So, while on first glance, it was fine I never, ever got that clearance with an aircraft landing - and for very good reasons. If the aircraft on the ILS had had to do a go-around, life could have become interesting very quickly. I was always held until the landing aircraft was well clear (ie ATC could see it was almost at the airfield) before they cleared me across. Indeed, legally, they could have given me a "You see the landing? Pass behind that"! But, no - always positive clearances. Got my vote ....... + gave me chance to enjoy the views of Greenwich and the City of London and "delayed" me a couple of minutes. OK, a bit unfair as LCY is "sleepy hollow" compared to DCA but, despite that, they were very friendly ..... but very strict!!!!!



So, when you are discussing (I think!!!) whether ATC elected to give PAT25 a "You visual? Pass behind" or whether it was "ordered" from on-high as it was deemed safe to do, ultimately, it is the ATCOs call on the day. Now, before I get flamed, do I blame the ATCO ? No! Well, why not? After all, he gave PAT permission! And yes, it was a "legal" clearance. But was it a wise clearance? When unpacking that little lot you have to look at a raft of Human Factors which influenced that ATCO on that night. He was on his own so, probably, the only way he could cope with all he had on his plate was to try and shift some responsibility onto PAT25 - one less thing for him to juggle. But even then, he needed to be monitoring which he clearly was - but while very busy with other approaches and departures so he just picked up a concern too late as the audio shows - "Are you sure you see the jet?". Another factor - was the strategy to use Route 4 while 33 was active something ATCers at DCA, over time, started in an effort to cut down radio traffic and speed things up? If so, had it been assessed and then monitored for adverse safety? While anecdotally, it seemed people were aware of "close calls", had any analysis taken place looking at the Databases? In the UK certainly, all the Airport Operator responsibility.

To the final "accountability" part re payments to families, the thing we have here is (and, folks, correct me if I've got this wrong) the FAA set the rules and the operate the Rules. Here, the CAA sets the rules and the Airfield Operator operates the rules. That is important - for eg, huge argument here in the UK about just how independent the UK's Military Flight Safety organisation is ..... as it is part of the Military. IMHO, what we have here are valid generic rules, some of which were simply not suitable in this specific location - just like crossing London City with an aircraft on approach - legal ...... but very unwise. As to who carries the can, well, as you said WR 6-3 , the legal beagles will get to the bottom of that ..... but it will take some time. I'll leave that side to you!!! My main question out of all of this is, why were not these issues flagged up by airport management for further investigation given it was something of an open "secret"? And where else (around the world) is this happening?

And, on that cheerful note...........! H 'n' H

Was the controller really on his own?

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

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

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

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.........

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

That is not the one I mean . The radar track video (a screen shot is on post 848 but the video is clearer) show a slight right turn less than a minute or so before the collision . Even if they were just correcting the course to be exactly on track, it makes no sense to turn towards the right to avoid a aircraft on finals on either 01 or worse 33. That is my point . What did they see,? or did they just requested visual separation as a standard call to proceed without restrictions and :" in sight" while still looking for the traffic as some US controllers discussed in another forum .

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

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

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

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

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

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

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

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

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

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

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

Since we\x92re discussing the DCA accident, let\x92s be clear about U.S. terminology as specified by 7110.65.

There is tower-applied visual separation . That is not relevant to the DCA accident.

There is also pilot-applied visual separation . That is what PAT25 requested and the LC approved.

As for the perfectly-safe visual separation, the DCA accident might have been avoided had the LC applied all of the elements of pilot-applied visual separation; i.e.

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