Pass Behind Page: 4 of 6

Commando Cody
February 05, 2025, 20:24:00 GMT
permalink Post: 11822518

Quote:

Originally Posted by BrogulT

And thank you for sharing your experience. I asked this earlier but haven't gotten a direct reply: If you know, what would have happened if the controller had asked PAT25 to "hold" at the holding point near Hains Point? Is that the function of those holding points and is there some set procedure or pattern?

DCA had multiple inbounds. With an acknowledged instruction to pass behind traffic that was reported in sight, holding isn't necessary and can set up problems of its own.

Subjects ATC DCA PAT25 Pass Behind Pass Behind (All)

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dbcooper8
February 05, 2025, 23:51:00 GMT
permalink Post: 11822641

Questions

Condolences to all impacted.
Questions:
Why was PAT 25 search light in the stowed position and not motored to a more forward position?
Why are PAT helicopters not M models with FD's so PAT 25 could have been coupled on route 4 while at 200' giving the PF more time to look for traffic?
Was there pressure to use NVG along route 4 to meet the hourly requirements for currency?
Why did PAT 25 not slow down or hold at Hains in order to pass behind the CRJ as per their clearance?
Why was it ops normal after a near miss the previous day and then only one crew chief instead of two for PAT 25?
Why was the controller task saturated?
Why over the years, as the airport got busier, someone didn't suggest, for night operations, only one aircraft on route 4 or only one aircraft on the approach to 33 at a time and prohibit simultaneous operations?

IMO while the CRJ was turning final to rwy 33 PAT 25 may have experienced the CRJ landing lights in the cockpit and may have chosen up and right rather than left and down. Note worthy, PAT 25 RAD ALT gauge scale changes dramatically at 200'.

Maybe an upgrade to Dulles with a high speed train connection...

Subjects ATC CRJ Close Calls Night Vision Goggles (NVG) Pass Behind Pass Behind (All) Route 4

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galaxy flyer
February 06, 2025, 01:54:00 GMT
permalink Post: 11822687

Quote:

Originally Posted by dbcooper8

By the time the lights were shining in PAT 25\x92s cockpit, it was way too late\x97collision was inevitable and unavoidable.

Not the latest model? Guess what, combat units get the latest models. These missions are transport, not combat roles. Budgets and priorities rule. There are VH-60s in the battalion, they\x92re probably not scheduled for check rides or training flights.

One RA does not rewrite the schedule, likely not even unusual in DCA. The previous crew may not have passed the event on. I\x92ve had numerous RAs, never a report. The NTSB has stopped asking for reports for events involving VFR traffic.

While nice to have, there\x92s no place for a second crew chief to have a forward view. And the CC may or may not be \x93in the loop\x94. They\x92re crew chiefs, not pilots. We had them on C-5 and they mostly slept in flight as they too much to do on the ground.

Subjects ATC CRJ Close Calls DCA NTSB Night Vision Goggles (NVG) Pass Behind Pass Behind (All) Route 4 TCAS RA VFR

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51bravo
February 06, 2025, 10:57:00 GMT
permalink Post: 11822897

Quote:

Originally Posted by Commando Cody

Tower pointed out the CRJ twice and PAT25 affirmed they had traffic in sight and twice requested visual separation, which was approved. Controller did everything right.

Question: In the last seconds:

Controller instructed very firmly: "PAT25, pass behind the CRJ"

There was no such readback, instead:
PAT25: "PAT25 has CRJ in sight, request visual separation"
Controller: "vis sep approved"

Does the "request visual separation" undo the "pass behind"?
(just trying to refresh my phraseology understanding, its long time passed, my PPL is not current a long time since)

Subjects ATC CRJ PAT25 Pass Behind Pass Behind (All) Pass Behind (PAT25) Phraseology (ATC) Separation (ALL) Traffic in Sight Visual Separation

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SATCOS WHIPPING BOY
February 06, 2025, 18:20:00 GMT
permalink Post: 11823141

Quote:

Originally Posted by Stagformation

Very unlikely the helo crew could actually identify the right traffic 7nm away in half a second. My guess is they instantly say, \x91traffic in sight, request visual separation\x92, because they know that any other response (inferring traffic not in sight) obliges ATC to apply minimum 500ft/1.5mi separation in class B airspace and then a whole can of worms ensues. No other option available to the controller as far as I can see.

Ref para 3.2.3. e. 2 here https://www.faa.gov/air_traffic/publ...l%20separation .

A can of worms or a mid-air collison. I'll take the can of worms please. I can't see any aircrew being worried to give a truthful response just to aid ATC, not when it is their lives at stake. If this does happen then that is a whole new set of lessons that need to be learned.

I have watched these comments in two threads with interest. Helo routes under busy approach lanes was (and I believe, still is) the norm at Boscombe Down when I arrived there in th eearly 90s. When the civvy incumbants left and the military took over we had to learn from scratch and one of the first things was to sort out the procedure for helicopters routing from Middle Wallop, along the railway line towards Boscombe Down before making a sharp right to go under the approach path to 23 before heading of north west into the Salisbury Plain play areas. As far as I remember this was a no-RT route and was a akin to a child crossing the road (look left, look right and when safe, cross). It was not unusal to have a jet on PAR and then a little blip appear about 2 miles finals crossing at 90 degrees. I seem to think this had been going on like this for years. After that it was mandated that a call to ATC must be made, and if traffic was busy, the helos held clear of the appraoch path. I cannot remember the exact details but think there was a150ft cap as well and a conspicuity squawk. Back then Boscombe was incredibly busy.

IMHO the crew on the helo were alerted to traffic, a misident occurs and they press on, maybe relaxing their altitude accuracy as they are not aware of any other threats besides the one they can see in the distance, which they will clearly pass behind as requested. They would have no clue as to aircraft type.

A very sad incident indeed and my heart goes out to all involved.

Subjects ATC Pass Behind Pass Behind (All) Separation (ALL) Traffic in Sight

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ATC Watcher
February 09, 2025, 17:01:00 GMT
permalink Post: 11825026

Just to put the things back into perspective : whether the controller had a radar display in front of him or not ,, whether there should have been a separate controller in the Heli frequency ,both would not have changed anything in this case since he delegated separation to the helicopter , The visual identification by the helicopter was confirmed ( twice) , instruction to pass behind was confirmed = controller no longer responsible , standard procedure in DC since the guys worked there , and he had a lot of other traffic to attend to.

To discuss what he could or should have done is just playing " Captain hindsight "

The procedure was wrong , the safety case botched , and as I understand, the " book " allowing all this was followed by both the controller and the helicopter pilot .
Let's discuss the procedures and visual separation delegation at night in busy airports instead on focusing on what the controller should have done , implying indirectly some form of responsibility in this accident..

Subjects ATC Pass Behind Pass Behind (All) Radar Separation (ALL) Visual Separation

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deltafox44
February 09, 2025, 18:15:00 GMT
permalink Post: 11825063

Quote:

Originally Posted by ATC Watcher

Not implying any form of responsibility to anyone, the "book" says that in the case of a visual separation, if the 2 traffics converge, the controller should advise the other pilot. Perhaps the same controller on both frequencies was too busy to do so, and a second controller would have helped.

cf FAA Order JO 7110.65AA 7.2.1.a.2 Pilot-applied visual separation

Quote:

(d) If the aircraft are on converging courses, inform the other aircraft of the traffic and that visual separation is being applied.
(e)Advise the pilots if the radar targets appear likely to merge.

Last edited by deltafox44; 9th February 2025 at 19:04 . Reason: adding source

Subjects ATC FAA Pass Behind Pass Behind (All) Radar Separation (ALL) Visual Separation

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island_airphoto
February 09, 2025, 19:15:00 GMT
permalink Post: 11825080

Quote:

Originally Posted by ATC Watcher

There is a general lesson and a specific lesson:
The specific one only applies to DCA, so unless you fly there for your job or want to fill out 1001 forms to get your own airplane in there, no worries, no one else does crazy stuff like that with helos.
The general one for me so far is how easy it is to see the wrong traffic at night and the next "do you see X" I get at night I am going to be triple-redundant sure and then some before saying I do.

Subjects ATC DCA Pass Behind Pass Behind (All) Radar Separation (ALL) Visual Separation

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malabo
February 09, 2025, 19:54:00 GMT
permalink Post: 11825090

Quote:

The general one for me so far is how easy it is to see the wrong traffic at night

We don\x92t know if they were looking at the wrong traffic or not, yet. We do know they hit the traffic they said they would pass behind. Might just be a military Blackhawk thing. A thousand lowtime Robbie pilots flying single-pilot are told to pass behind landing traffic routinely and somehow manage to do it. On this thread you\x92ve read that Blackhawks need two crew chiefs in the back to help look out for traffic, and that the pilots are obliged to wear NVG on this route even though they can\x92t see **** with them on in the urban cultural lighting.

Done this myself for 50 years, night, single-pilot, high-density airports, single and multiengine, never had an issue identifying the aircraft tower pointed out to me.

Keep looking.

Subjects Blackhawk (H-60) Night Vision Goggles (NVG) Pass Behind Pass Behind (All)

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YRP
February 09, 2025, 20:32:00 GMT
permalink Post: 11825106

Quote:

Originally Posted by ATC Watcher

Absolutely agree.

A second controller -might- have had more time to observe the conflict. They -might- have twigged and second guessed the helo's separation. But they very well might not have. The spacing might have been close enough to the every day occurances that the controller might not have been able to tell.

Having the helicopters on a separate frequency from the fixed wing would certainly not have helped anyone's situational awareness.

Subjects ATC Pass Behind Pass Behind (All) Radar Separation (ALL) Situational Awareness Visual Separation

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21600HRS
February 10, 2025, 08:22:00 GMT
permalink Post: 11825313

The Black Hawk crew had lost totally their situational awareness. If you are instructed to pass behind a traffic which is landing on rwy 33 how can you be on final rwy 33 before the traffic has passed you? Perhaps they noticed that they were approaching the final of rwy 33 and started a right hand climbing turn, but too late.
CRJ was possible behind the windsield frames in the first sight but anyway it was not conflicting traffic while it was on the base for rwy 33. Final turn at below 500ft doesn’t make it any easier for the helicopter to realize/react to the changing situation.

One thing came to my mind: was the PAT 25 avoiding the traffic by flying ahead of the CRJ instead behind it in first place? ”Pass behind” was told only 18 seconds before the impact.

Last edited by 21600HRS; 10th February 2025 at 12:44 .

Subjects Blackhawk (H-60) CRJ Pass Behind Pass Behind (All) Situational Awareness

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deltafox44
February 14, 2025, 19:54:00 GMT
permalink Post: 11828159

Just heard NTSB briefing. It seems that the scapegoat will not be any of the humans involved, nor even the procedures, but the altimeter system of the black hawk (a 100 ft discrepancy) and the radio (they did not hear "circling" and "pass behind")

Subjects Blackhawk (H-60) NTSB Pass Behind Pass Behind (All)

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parabatix
February 14, 2025, 20:29:00 GMT
permalink Post: 11828183

deltafox44
Not at all. The briefing indicated there may be a possibility that the altimeter in the BlackHawk displayed an inaccurate altitude reading and that the discrepency was in the order of approx 100' given the height at which the collision is known to have occurred.
Briefing the RT comms, NTSB stated that a portion of the ATC instruction to the BlackHawk to 'pass behind the CRJ' was received in the Blackhawk (according to the CVR), truncated due to the BlackHawk keying the mic at the same time. Apparently, the words 'pass behind the' were missing from the BlackHawk CVR.

Last edited by parabatix; 14th February 2025 at 20:35 . Reason: 'in rely to'

Subjects ATC Blackhawk (H-60) CRJ NTSB Pass Behind Pass Behind (All)

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DIBO
February 14, 2025, 21:03:00 GMT
permalink Post: 11828208

Quote:

Originally Posted by deltafox44

(my bold in quote) well.... that doesn't surprise me.
For a couple of days now, was thinking about posting something on an "extra noise" I keep hearing in the R/T comms, when TWR gives the ' pass behind ' instruction. Was wondering whether TWR's Tx wasn't stepped over by someone.
My first impression was that the extra noise came from an radio call from a turbine helicopter (given the typical background noise often heard in radio calls from turbine helicopters). And was wondering if it wasn't PAT25 that started replying to TWR's first ' in sight? ' call, effectively blocking part of TWR's second call, the ' pass behind ' part of the instruction.

In attached mp3 (in .zip per forum attachment requirements) around 00:05 I hear this 'extra noise'.

Edit:
well, this seems to confirm my initial impression:

Quote:

Originally Posted by parabatix

Briefing the RT comms, NTSB stated that a portion of the ATC instruction to the BlackHawk to 'pass behind the CRJ' was received in the Blackhawk (according to the CVR), truncated due to the BlackHawk keying the mic at the same time. Apparently, the words 'pass behind the' were missing from the BlackHawk CVR.

Attached Files

KDCA1-Twr-Midair - PAT25 pass behind.zip (89.1 KB, 20 views)

Last edited by DIBO; 14th February 2025 at 21:07 . Reason: last posts with NTSB info seem to confirm my suspicion

Subjects ATC Blackhawk (H-60) CRJ NTSB PAT25 Pass Behind Pass Behind (All)

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Lonewolf_50
February 14, 2025, 21:10:00 GMT
permalink Post: 11828211

Quote:

Originally Posted by gevans35

Are they suggesting that 100' vertical separation would have been okay?

No, hence the tower telling the Blackhawk to pass behind.

Quote:

Originally Posted by EXDAC

Landing flap, 9 deg pitch up, and full up elevator! That is what I heard NTSB report at today's briefing.
No one in the assembled press made any comment and so likely no one understood that was not normal or what it most likely indicated.

Seems to me like a reaction to seeing the Blackhawk right before impact and a reflex/reaction with intent to avoid.

The subtext for me is that the Blackhawk crew never saw them...but there's more for the NTSB to sort out, as the lady was VERY CLEAR about.

Subjects Blackhawk (H-60) NTSB Pass Behind Pass Behind (All) Separation (ALL) Vertical Separation

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Wide Mouth Frog
February 14, 2025, 21:30:00 GMT
permalink Post: 11828220

Quote:

Originally Posted by parabatix

I'm not sure they did say that about the altimeter, they said that there was bad pressure altitude data recorded on the FDR. That's not the same as saying the altimeter display was wrong, although it does mean that it's going to be hard to infer what was actually displayed on the Baro Alts. I would have thought a military crew would be pretty solid on altimeter cross checks though so I think that's all a bit of a red herring. The Potomac is (give or take the tide) at sea level so I think we can be pretty confident that the RadAlt figure of 278ft is good for an altitude too.

Subjects ATC Blackhawk (H-60) CRJ NTSB Pass Behind Pass Behind (All)

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deltafox44
February 14, 2025, 22:44:00 GMT
permalink Post: 11828270

Quote:

Originally Posted by Lonewolf_50

No, hence the tower telling the Blackhawk to pass behind.
Seems to me like a reaction to seeing the Blackhawk right before impact and a reflex/reaction with intent to avoid.

The subtext for me is that the Blackhawk crew never saw them...but there's more for the NTSB to sort out, as the lady was VERY CLEAR about.

NTSB did not say (and nobody asked

) if there had been any discussion in the black hawk cockpit about the CRJ (where it was, whether the PF did see it or not) when PM requested visual separation

Last edited by deltafox44; 14th February 2025 at 23:19 .

Subjects Blackhawk (H-60) CRJ NTSB Pass Behind Pass Behind (All) Separation (ALL) Visual Separation

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Lead Balloon
February 15, 2025, 04:03:00 GMT
permalink Post: 11828354

It appears from the NTSB's most recent press conference that the instruction "pass behind the CRJ" was not heard in the helo's CVR and, therefore by inference, not heard by the crew. Am I correct in assuming that there is no requirement to readback an instruction like that in the USA? ATC appeared not to expect one.

Subjects ATC CRJ Pass Behind Pass Behind (All)

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Commando Cody
February 15, 2025, 05:36:00 GMT
permalink Post: 11828365

Quote:

Originally Posted by Lead Balloon

The Aeronautical Information Manual lists a number of instructions that should be read back, but there are none that must be read back (unless the controller specifically requests). "Pass behind..." is not even one of the "should" be read back instructions, so ATC wouldn't be bothered by not getting a read back. Frankly, if there was a requirement to fully read back all things like "Pass behind..." the frequency would be constantly full. In any case, whether PAT25 heard the "Pass behind" or not, it had already said that it was providing its own visual separation, so not hearing an instruction to pass behind does not take away the requirement to maintain separation.

Last edited by Commando Cody; 15th February 2025 at 07:45 . Reason: precision

Subjects ATC CRJ PAT25 Pass Behind Pass Behind (All) Separation (ALL) Visual Separation

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Easy Street
February 15, 2025, 10:24:00 GMT
permalink Post: 11828489

Quote:

Originally Posted by ATC Watcher

absolutely . the altimeter talk is just a distraction or at best contributing factor, Not the cause .. which brings us back to the safety assessment of the procedure , which the NTSB did not mention at all,, but I am sure , or at least I hope they will go into in their final report.

+1 to everything you and Wide Mouth Frog said.

I sincerely hope the NTSB can avoid being distracted by the distractions of altimetry and the missing ATC words on the Blackhawk CVR.

Upthread, Luca Lion calculated the 3 degree PAPI approach path as crossing the eastern riverbank at 270ft. If that's correct, then the CRJ's 313ft radar height 2 seconds before collision puts it at least 43ft above the approach path, so the Blackhawk's radio height deviation of 78ft would have contributed only about 35ft to the erosion of any intended "procedural separation" (*) between the aircraft. Or, to put it another way, the same outcome would have resulted if the Blackhawk had been at 235ft radio and the CRJ on the glide. Height keeping of plus or minus 35ft can only be achieved by instrument flying, which is obviously not compatible with visual separation (or indeed VFR) so cannot be reasonably cited as part of a safety case for the procedure. And of course a landing aircraft could easily be below the glide. Altimetry and height keeping are not the cause of this accident.

Missing the word "circling" wouldn't have influenced the helo crew getting visual with the CRJ at the time of the trasnmission. At best, it would have given them an extra nudge that "runway 33" (which was audible) meant the CRJ would be taking an easterly flight path. Missing "pass behind" with only a few seconds to collision was irrelevant if, as seems likely, the helo crew did not see the CRJ at that point.

(*) The quotes around "procedural separation" are intended to convey a tone of disgust and sarcasm.

Last edited by Easy Street; 15th February 2025 at 10:47 .

Subjects ATC Blackhawk (H-60) CRJ Final Report NTSB Pass Behind Pass Behind (All) Radar Separation (ALL) VFR Visual Separation

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