Posts about: "Separation (ALL)" [Posts: 442 Page: 1 of 23]ΒΆ

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Cloud Cutter
January 30, 2025, 04:39:00 GMT
permalink Post: 11816865
This could well be an example of why visual separation at night is not a good idea.

Subjects Separation (ALL)  Visual Separation

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BFSGrad
January 30, 2025, 05:23:00 GMT
permalink Post: 11816892
Originally Posted by Capi_Cafre'
A late change to 33 had the potential to put the jet low and in conflict with the helicopter corridor.
Don\x92t think it was a late change. Listening to LiveATC, local controller (LC) calls the CRJ at 1200 ft, inbound 33, over the Wilson Bridge as a traffic advisory to PAT25. Don\x92t hear reply but it sounds like LC then says \x93visual separation approved.

LC then approves AAL1630 for immediate takeoff runway 1 with advisory of CRJ on 2-mile left base for 33.

LC queries PAT25 \x93do you have the CRJ in sight\x94? No reply heard but LC then directs PAT25 to pass behind the CRJ.

PAT25 may have been watching next in sequence, AAL3130, landing runway 1, instead of CRJ.

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

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Ignition Override
January 30, 2025, 06:11:00 GMT
permalink Post: 11816907
Unhappy
My extra prayer, other than for the victims' families, and possibly for a truly despondent ATC controller , is that No children were on the CRJ.

All of my flights into DCA (1985-2017) --mostly DC-9, MD-88, 717 --were on the profiles over the Potomac River, to land on Rwy 19, or for Rwy 01, flying the ILS or a charted visual while going north over the river.
We Never were required to use "see-and-avoid" to maintain safe separation from helicopters or any fixed-wing aircraft iirc.

Was the ATC controller so Busy watching Other aircraft on his radar that he could not clear the helicopter to fly a southeast (ie 150 *) heading--- to keep it well east of the final approach for Rwy 33, until the CRJ was clearly west of the heli, on final approach?
Or a similar separation?
Last edited by Ignition Override; 30th January 2025 at 06:25 .

Subjects ATC  CRJ  DCA  Radar  Separation (ALL)

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Someone Somewhere
January 30, 2025, 07:27:00 GMT
permalink Post: 11816947
Originally Posted by WideScreen
Not sure how an approach like this one can be flown with an ILS, even a GPS based approach I have my doubts to be able to fly that precise, etc.
I was talking about visual separation; I should have been clearer.

I think, the better option would be to not rely on "bright lights" but suitably illuminated big surfaces, IE an airplane should illuminate its own surfaces. For this particular case, that might not have made a big difference, given the near head-on approach for a long time.

This accident was certainly "setup" in the procedures defined in this area, heavily relying on Humans not making (altitude (settings)) mistakes and Humans detection opportunities, for which we all know, the human is not really that well-designed for from scratch.

For this case, the helicopter corridor was designed to be below the approach path, though when the human makes even a small mistake and/or the weather makes the approach path a bit lower, things can go haywire quite easily.
Might have helped the CRJ see the helicopter (except a military helicopter probably won't be illuminated anyway). But if the helicopter crew has CRJ landing lights pointing at them, are they going to see anything? It seems like another poor-quality band-aid on top of the fundamental problem of trusting see-and-avoid and voice comms.

RVSM is 1000ft at higher altitudes; even if things had gone 100% to plan, this would have only provided, what, <300ft vertical separation? Is wake turbulence a threat to helicopters?


Subjects CRJ  Separation (ALL)  Vertical Separation  Visual Separation

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cbradio
January 30, 2025, 07:33:00 GMT
permalink Post: 11816953
Originally Posted by LessThanSte
​​​​​​
Did ATC switch attention to something else, and miss the opportunity to intervene when it became apparent that both aircraft were getting close. Etc.

Seems baffling that this could happen in such a tight controlled environment...

​​
If a helicopter is "passing behind" a jet they have previously sighted, they are going to get close. That's the point of visual separation.

doing like that at night, with so many aircraft and ground clutter, I'm not so sure about

Subjects ATC  Separation (ALL)  Visual Separation

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LOWI
January 30, 2025, 07:39:00 GMT
permalink Post: 11816957
Originally Posted by C2H5OH
Now close this darn airport which is there for convenience of the political class and their servants only. Fix parallel approches in SFO, reduce movements at JFK by 30%, etc p.p., the list is long. Or have a deja-vu in a couple of months.
Absolutely agree! Lufthansa refused the night visual separation a couple of years ago at SFO for this very reason! They were punished by US ATC because of this! We must never take these stupid risks with passengers onboard!

But what will be the response to this crash? Increase the 1500 hour rule most likely.... Europe has guys with 200 hours flying 737s and A320s between countries where English is the 2nd language!

Subjects ATC  Separation (ALL)  Visual Separation

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fdr
January 30, 2025, 07:54:00 GMT
permalink Post: 11816967
Originally Posted by Someone Somewhere
I was talking about visual separation; I should have been clearer.

Might have helped the CRJ see the helicopter (except a military helicopter probably won't be illuminated anyway). But if the helicopter crew has CRJ landing lights pointing at them, are they going to see anything? It seems like another poor-quality band-aid on top of the fundamental problem of trusting see-and-avoid and voice comms.
The video shows the lights of the helicopter quite clearly, approaching the CRJ from about 2 o'clock to the CRJ.

Subjects CRJ  Separation (ALL)  Visual Separation

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WideScreen
January 30, 2025, 08:37:00 GMT
permalink Post: 11816997
Originally Posted by Someone Somewhere
From this angle, yes. With ground clutter and looking at the helicopter from the other side...
With the CRJ crew probably having their attention focused to aim for runway 33, while performing the circle to approach. With a "clear to land" obtained, they even might be less aware, there might be something out there on a collision course with them.

Not to say, the helicopter declared a "CRJ in sight", which also implies from that moment on, the separation became their responsibility.

When flying myself, I am very hesitating to "accommodate" to ATC's information about other aircraft around me, since I then take over the separation responsibility, even when losing sight of the other aircraft(s).

Subjects CRJ  Separation (ALL)

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mobov98423
January 30, 2025, 08:41:00 GMT
permalink Post: 11817000
Originally Posted by WideScreen
With the CRJ crew probably having their attention focused to aim for runway 33, while performing the circle to approach. With a "clear to land" obtained, they even might be less aware, there might be something out there on a collision course with them.

Not to say, the helicopter declared a "CRJ in sight", which also implies from that moment on, the separation became their responsibility.

When flying myself, I am very hesitating to "accommodate" to ATC's information about other aircraft around me, since I then take over the separation responsibility, even when losing sight of the other aircraft(s).
yeah,atc had nothing to do with this ;(

Subjects CRJ  Separation (ALL)

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Alpine Flyer
January 30, 2025, 09:10:00 GMT
permalink Post: 11817027
Originally Posted by Chock Puller
Helicopter Low Level Routes are standardized through out the DC area.

Military Operations are 24/7/365 due to National Security issues.

https://www.loc.gov/resource/g3851p....,0.268,0.125,0



According to the procedure map Route 4 (which seems to be the one they were closest to) is supposed to be flown at or below 200ft north of Wilson Bridge. The Radar plots that surfaced so far show the helicopter above 300ft. Even if they misset their altimeter they probably have a radar altimeter and a 75% difference in height should be apparent to a crew familiar with low-level flying.

I have never flown there but if there's regular helicopter traffic 150ft below an ILS or circling approach airline crews familiar with the airport might tend to disregard TCAS proximate traffic, etc. as normal backdrop chatter.

Even when flying behind similar aircraft on an ILS in daylight and good visibility it takes quite some time to see that preceding traffic is slowing down as it only starts to "grow" at an alarming rate when quite close. I have witnessed that twice, once caused by self and another time caused by mismatched speed instructions from ATC. I have resolved to never accept visual separation to preceding traffic at night and while the European aversion to visual approaches might be excessive, high density night ops based on visual separation don't seem to be a good idea even without that crash.


Subjects ATC  Circle to Land (Deviate to RWY 33)  Radar  Route 4  Separation (ALL)  TCAS (All)  Visual Separation

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MissChief
January 30, 2025, 10:23:00 GMT
permalink Post: 11817093
Visual Separation is a recipe for a collision. The US ATC use it far too often, setting a trap for many an unwary crew. At night, in complex and crowded airspace, Visual Separation should not be used. I nearly came a cropper in daytime at MCO, when my gung-ho CM1 accepted it just as we entered cloud while joining final approach at 8 miles. So the blame can lie on both/all sides.

Remains to be seen here.

Subjects ATC  Separation (ALL)  Visual Separation

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Stringy
January 30, 2025, 10:42:00 GMT
permalink Post: 11817113
Originally Posted by 172_driver
I used to enjoy the free use of airspace in the US, but I always told myself and others; It's not for anyone who under performs.
That's an indirect way of saying that the system is flawed and is relying too much on humans to stop it from failing.
Originally Posted by EDLB
So a midair in the most tightly restricted and controlled airspace in the world. How many official agents were watching this in real time without taking action?
The problem is an over reliance on visual separation in congested and complicated airspace. An aircraft claims it has the traffic in sight, therefore taking responsibility for separation, and ATC moves on to their next task. The fact that this is allowed with commercial aviation over DC (or any major US city) when there's potentially hundreds of lives at stake in the air, never mind the lives on the ground, is staggering.

Subjects ATC  Separation (ALL)  Traffic in Sight  Visual Separation

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Capt Fathom
January 30, 2025, 10:56:00 GMT
permalink Post: 11817122
Originally Posted by Stringy
The problem is an over reliance on visual separation in congested and complicated airspace. An aircraft claims it has the traffic in sight, therefore taking responsibility for separation, and ATC moves on to their next task.
I remember the Lufthansa A380? that refused a night visual approach into SFO and subsequently diverted to Oakland.

Subjects ATC  Separation (ALL)  Traffic in Sight  Visual Separation

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nicolai
January 30, 2025, 11:10:00 GMT
permalink Post: 11817126
Neither Lufty nor Iberia will accept a visual night approach (as far as I recall).

But that wouldn't have saved them here, since they'd still have been hit by someone else trying visual separation at night in this case.

The Lufty A380 that went to Oakland looked a lot like they were being sent there by ATC to punish them, since it can't have been news to the SFO controllers that Lufty won't do that approach - when they come there every night at about the same time. The ATC kept him waiting and the Lufty Captain was pretty arsey to the ATC and then they sent him to Purgatory (OAK).

Subjects ATC  Separation (ALL)  Visual Separation

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ATC Watcher
January 30, 2025, 11:23:00 GMT
permalink Post: 11817135
Originally Posted by nicolai

But that wouldn't have saved them here, since they'd still have been hit by someone else trying visual separation at night in this case.
).

That is part of the safety lectures' I gave ; in VFR ,using the see and avoid concept, the danger is not the one you see but the one you do not see and : : You can fly as safe as you want , the danger will come from someone else which does not ". .
Airliners cockpits are not designed for see and avoid.. not on daylight , so much worse at night where distance of lights is almost impossible to determine

@ 172 Driver : I used to enjoy the free use of airspace in the US
yes me too but above Nevada , not under the Glideslope close to a runway of a major airport at night ..


Subjects See and Avoid  Separation (ALL)  VFR  Visual Separation

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Upside Down
January 30, 2025, 11:29:00 GMT
permalink Post: 11817139
Originally Posted by MichaelKPIT
I don\x92t know how accurate this is but the CNN analyst is saying that horizontally they\x92d have been ok. The helicopter path is beneath the published approach and should not have been a problem, but it looks like the helicopter was too high\x85
The Route 4 restrictions are in the Terminal Chart somebody else posted further up the thread: \x93Rt4: Fort Washington over Potomac River to Wilson Bridge. Then via East bank of Potomac River to Anacostia River. Intercept Route 1 at Anacostia River. Altitudes: At or below 600 feet MSL to Wilson Bridge. Begin descent from 600 feet MSL to arrive at 300 feet MSL over Wilson Bridge. Then at or below 200 feet MSL North of Wilson Bridge.\x94

The chart itself shows the <not above 200 MSL> symbol for the segment where the collision took place. That combined with the \x93via East bank\x85\x94 provides (some) procedural separation with traffic on final.. not much but some if the Route 4 traffic follows the east bank\x85 and stays below 200\x92\x85.

Subjects CNN  Route 4  Separation (ALL)

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Locked door
January 30, 2025, 11:39:00 GMT
permalink Post: 11817145
The whole USA aviation sector needs root and branch reform, there have been so many near misses in recent years that this accident was inevitable, it was just a question of when.

The majority of people inside the system don\x92t realise how bad it is because it\x92s all they\x92ve ever known. We have American contributors here who routinely tell us it\x92s ok to switch to TA only to avoid \x93nuisance\x94 RA\x92s, who will not follow an RA as they have the traffic in sight, who will accept visual separation at night (day is bad enough) or very late visual switches, who think LAHSO is a good idea. USA ATC think it\x92s acceptable to \x93slam dunk\x94 a heavy jet, get shirty when foreign operators refuse a questionable clearance, literally forget about an aircraft once it has accepted visual separation. The system allows uncontrolled VFR traffic within 500ft of commercial operations which is madness.

I operated the 747-400 around the planet for over a decade, the USA was one of the most threat laden environments we went to. Lovely people, just insane procedures. In that time I experienced a TCAS RA on vectors to JFK, was sent around and put in the hold as punishment on short final in Miami for refusing LAHSO, had multiple super high workload approaches to SFO combined with the crazy policy of pairing aircraft on approach. I witnessed a Singapore aircraft being refused a diversion to Boston from JFK fifteen minutes after they stated what time they would be leaving the hold and where they would be going resulting in a fuel mayday and an unplanned diversion to a regional airport. I lost count of the times I was chastised for refusing a visual approach and visual separation in congested airspace or a very late visual switch.

On most of the planet the human is the last line of defence in a multi layered safety environment. In the USA the human is often the only line of defence, while the environment they are in is super high workload significantly reducing their capacity to trap safety issues.

Unless there is a marked attitude shift in all parties involved in aviation in the USA this will happen again, potentially quite soon.

Stay safe out there

LD

Subjects ATC  Close Calls  Land and Hold Short  Separation (ALL)  TCAS (All)  TCAS RA  Traffic in Sight  VFR  Visual Separation

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biscuit74
January 30, 2025, 12:30:00 GMT
permalink Post: 11817187
Originally Posted by Semreh
We should look at how to engineer things better to avoid this happening: this does not mean 'more training', 'brighter lights', or putting additional human-operated steps in already complex procedures.
Strictly, 'human engineering' or in other words poor understanding of how humans operate and what our limitations are.

A 'human resource' failure rather than 'engineering' per se - though I fully agree with your comments otherwise. Remove the risk entirely - the best prevention, rather than try to minimise the probability of failure by adding more steps or 'aids'.

Low level helicopter Route 4 makes sense for the ease of helicopter positioning point of view and minimising noise etc impacts - following a river. But not right under an approacj path and especially not at night, using visual separation !

Subjects Route 4  Separation (ALL)  Visual Separation

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Jojobray
January 30, 2025, 13:16:00 GMT
permalink Post: 11817227
Poignant truth
Originally Posted by Locked door
The whole USA aviation sector needs root and branch reform, there have been so many near misses in recent years that this accident was inevitable, it was just a question of when.

The majority of people inside the system don\x92t realise how bad it is because it\x92s all they\x92ve ever known. We have American contributors here who routinely tell us it\x92s ok to switch to TA only to avoid \x93nuisance\x94 RA\x92s, who will not follow an RA as they have the traffic in sight, who will accept visual separation at night (day is bad enough) or very late visual switches, who think LAHSO is a good idea. USA ATC think it\x92s acceptable to \x93slam dunk\x94 a heavy jet, get shirty when foreign operators refuse a questionable clearance, literally forget about an aircraft once it has accepted visual separation. The system allows uncontrolled VFR traffic within 500ft of commercial operations which is madness.

I operated the 747-400 around the planet for over a decade, the USA was one of the most threat laden environments we went to. Lovely people, just insane procedures. In that time I experienced a TCAS RA on vectors to JFK, was sent around and put in the hold as punishment on short final in Miami for refusing LAHSO, had multiple super high workload approaches to SFO combined with the crazy policy of pairing aircraft on approach. I witnessed a Singapore aircraft being refused a diversion to Boston from JFK fifteen minutes after they stated what time they would be leaving the hold and where they would be going resulting in a fuel mayday and an unplanned diversion to a regional airport. I lost count of the times I was chastised for refusing a visual approach and visual separation in congested airspace or a very late visual switch.

On most of the planet the human is the last line of defence in a multi layered safety environment. In the USA the human is often the only line of defence, while the environment they are in is super high workload significantly reducing their capacity to trap safety issues.

Unless there is a marked attitude shift in all parties involved in aviation in the USA this will happen again, potentially quite soon.

Stay safe out there

LD
Sadly this is probably the most honest and accurate description of flying into the USA I\x92ve read in many years.

Subjects ATC  Close Calls  Land and Hold Short  Separation (ALL)  TCAS (All)  TCAS RA  Traffic in Sight  VFR  Visual Separation

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JRBarrett
January 30, 2025, 13:20:00 GMT
permalink Post: 11817229
Originally Posted by Someone Somewhere
I was talking about visual separation; I should have been clearer.



Might have helped the CRJ see the helicopter (except a military helicopter probably won't be illuminated anyway)
Military aircraft are required to have standard external lighting when operating in civil airspace. In the zoomed video clip of the collision, you can see the helicopter had a strobe light. But with the relative positions, it probably would have been difficult for the CRJ crew to have seen the Blackhawk - especially since they were probably looking forward to concentrate on the runway.

Subjects Blackhawk (H-60)  CRJ  Separation (ALL)  Visual Separation

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