ATC Page: 15 of 31

WHBM
February 03, 2025, 20:31:00 GMT
permalink Post: 11820870

Quote:

Originally Posted by Lonewolf_50

The right turn does not make sense.

If the guess that PAT25 saw the traffic for 01 (further south,who was #2 for landing, with the CRJ being #1) and not the traffic for 33, they were still advised by ATC to pass behind their traffic .

There were a number of aircraft around in the dark, which makes repeated unqualified reference just to "the CRJ" quite liable to error. I still wonder if the "Can you see the CRJ ... pass behind the CRJ" was being interpreted as the aircraft on the ground lining up on 01, the nearest aircraft to them and just on their right. They could see it, and they turned to pass behind it.

Subjects ATC CRJ PAT25 Pass Behind Pass Behind (All)

Links are to this post in the relevant subject page so that this post can be seen in context.

1 recorded likes for this post.

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

ATC Watcher
February 03, 2025, 21:07:00 GMT
permalink Post: 11820895

Quote:

Originally Posted by MPN11

That is a question I posed way back. Does DCA Tower have a slaved radar display?

I do not know , what kind and how it is used. Some US controllers said in another forum they now have one , but what is it , where it is located and what the procedures are I do not know. Normally at large airports you have a radar picture repeater for situation awareness not for providing radar control unless you are in a TWR-APP combined facility of course , but DC is not.
and

Quote:

Does a non-trained/qualified controller have the authority to use that data in extremis?

if you mean in emergency , to prevent a collision ? , yes absolutely because in legal terms you always have the duty of care That is what the judge will come back to in the end. Now that said, where was the display located ? remember the guy was working 2 positions at same time . If there was a radar repeater display somewhere , was it located at the position he was working from ? The NTSB investigation will tell us that
.
If you are a controller you know how we work , Problem identified , = Conflict with PT detected , solution found = delegate separation , delegation accepted = problem solved. Next ... The guy was quite busy with departing and arrival traffic in runway one . Now of course with hindsight ,, what he should, and could perhaps have done is very easy for us to say . Feel very sorry for the guy . I hope he is not made the scapegoat for this mess.

Subjects ATC DCA NTSB Radar Separation (ALL)

Links are to this post in the relevant subject page so that this post can be seen in context.

10 recorded likes for this post.

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

JRBarrett
February 03, 2025, 21:44:00 GMT
permalink Post: 11820928

Quote:

Originally Posted by MPN11

That is a question I posed way back. Does DCA Tower have a slaved radar display? Does a non-trained/qualified controller have the authority to use that data in extremis? Personally, as an ATCO, and presented with imminently co-altitude and virtually head-on conflicting traffic, I would have intervened. But then I was always an interventionist Tower controller!

My earlier questions remain unanswered \x85 does DCA Tower have a slaved radar display ?
And thus could Tower have used that data to direct PAT21 out of the way, regardless of qualification or licensing? Or did Tower have a Radar qualification anyway, but didn\x92t use it?

I can\x92t speak for DCA, but my local Class D airport (KELM) has had a radar repeater in the tower cab since the late 1980s, and all the local controllers use it. I would think DCA almost certainly has one. The radar repeater is not used to give vectors to aircraft, but as an aid to the controller\x92s situational awareness.

Subjects ATC ATCO DCA Radar Situational Awareness

Links are to this post in the relevant subject page so that this post can be seen in context.

No recorded likes for this post (could be before pprune supported 'likes').

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

GroundedDinosaur
February 03, 2025, 21:46:00 GMT
permalink Post: 11820932

Altimeter setting vs Altimeter error amount?

The Helicopter wasn't landing at DCA, but, most likely would have the airports barometric setting in it's altimeter? If it was off by 0.2 inches, that would be about 200 ft?
I assume the altitude reading that the Altimeter in the aircraft displays in the cockpit is identical to the Transponded signal that ATC shows on it's screen? Is there a chance
that the Helicopter would have a different altimeter setting set? A new ATIS came out recently, or a pressure front was moving in?

Subjects ATC DCA

Links are to this post in the relevant subject page so that this post can be seen in context.

No recorded likes for this post (could be before pprune supported 'likes').

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

Jetstream67
February 03, 2025, 22:06:00 GMT
permalink Post: 11820948

Quote:

Originally Posted by GroundedDinosaur

I'm not sure this is the key point here. 100ft vertical separation at 150 Knots +/- equipment error in any safety plan is going to go wrong one day.
Although the route / approach crossed the main plan was surely to never let two aircraft on different courses /stages get even 10 times that close in passing . . which takes us back to the real issue

Subjects ATC DCA Separation (ALL) Vertical Separation

Links are to this post in the relevant subject page so that this post can be seen in context.

No recorded likes for this post (could be before pprune supported 'likes').

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

YRP
February 03, 2025, 22:45:00 GMT
permalink Post: 11820974

Quote:

Originally Posted by Undertow

They'd already said "Tower, we had an RA. Brickyard 4514 is going around" and that was acknowledged. They were then switched to Potomac who confirmed radar contact and asked reason for go around again. I would hope Potomac had seen/heard the "CA". But then after this everyone just carries on as if this is all perfectly normal until we all know what happened the very next day.

Potomac Approach is not in the same building (or at least room) as the Tower controller.

He\x92s asking the reason to find out what the a/c wants: sequence for another approach, divert due weather, hold to work out a technical fault.

Tower could have passed it on the hotline but it is probably normally more efficient to just have the a/c say.

Working about the safety implication of why the RA and what it says about the procedure is not something for the radio.

Subjects ATC Radar Republic Airways Flight 4514 Go-around

Links are to this post in the relevant subject page so that this post can be seen in context.

No recorded likes for this post (could be before pprune supported 'likes').

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

Undertow
February 03, 2025, 23:03:00 GMT
permalink Post: 11820991

Quote:

Originally Posted by YRP

Potomac Approach is not in the same building (or at least room) as the Tower controller.

Working about the safety implication of why the RA and what it says about the procedure is not something for the radio.

Seems it was not something for anywhere not just the radio. That was the problem.

Subjects ATC

Links are to this post in the relevant subject page so that this post can be seen in context.

No recorded likes for this post (could be before pprune supported 'likes').

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

framer
February 03, 2025, 23:19:00 GMT
permalink Post: 11821007

Quote:

Either way, the controller does not have enough information to use a heading \x97 neither to know one is needed nor what it should be .

I have never flown in the United States so am not sure, but if this was Australia the controller couldn\x92t give the helicopter a vector while it is below the minimum vectoring altitude anyway. I would be surprised if the controller in DC was able to legally issue a heading instruction to the Blackhawk while it is at or below 200ft at night. Can one of the American readers correct me if I am wrong?
Thanks

Subjects ATC Blackhawk (H-60)

Links are to this post in the relevant subject page so that this post can be seen in context.

1 recorded likes for this post.

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

DIBO
February 03, 2025, 23:26:00 GMT
permalink Post: 11821010

Quote:

Originally Posted by framer

not an American readers, but was thinking the same couple of days ago, so I found this:

Quote:

Vector aircraft: At or above the MVA or the minimum IFR altitude except as authorized for radar approaches, radar departures, special VFR, VFR operations , or by paragraph 5-6-3 , Vectors Below Minimum Altitude.

https://www.faa.gov/air_traffic/publ...section_6.html

Subjects ATC Blackhawk (H-60) IFR Radar VFR

Links are to this post in the relevant subject page so that this post can be seen in context.

No recorded likes for this post (could be before pprune supported 'likes').

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

SAM 2M
February 04, 2025, 00:28:00 GMT
permalink Post: 11821044

Suggested policies for review in the investigation

Whilst the rules differ between different countries, I am sure the following will be evaluated during the investigation:

- Any policy that permits visual separation from traffic at NIGHT should be reviewed.

- Any policy that permits routes - especially with such minimal planned separation - that cross final approach tracks should be reviewed.

- Any policy that permits 'band-boxing' of UHF and VHF radio communication frequencies should be reviewed, especially as it does not enable the crew of the UHF and VHF aircraft to hear the transmissions of the other crew. This reduces flight crew situational awareness (SA).

Some other items not directly related to this incident, but that could lead to collisions are:

- Land and Hold Short (LAHSO) operations should be reviewed.

- Clearing aircraft to land with traffic ahead but yet to land, should be reviewed. (e.g. "XXXX123 number 4 cleared to land")

- Having Ramp areas uncontrolled by ATC.

- Encouraging crew to 'report visual' (and thus becoming completely responsible for their own separation from that moment) should be reviewed.

787 Capt / SE / TRI / TRE

Subjects ATC Land and Hold Short Separation (ALL) Situational Awareness Visual Separation

Links are to this post in the relevant subject page so that this post can be seen in context.

5 recorded likes for this post.

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

Equivocal
February 04, 2025, 00:44:00 GMT
permalink Post: 11821056

Quote:

Suggested policies for review in the investigation

So, you mean make it like home?

There are many comments in this thread which say procedure X should not be allowed. The procedures that were applied by ATC immediately before the accident are \x91standard\x92 and used the world over. None are intrinsically unsafe but their application (as with all the other rules that need to be followed) needs to be appropriate. Visual separation at night is likely to be fine on a clear night with just two or three aircraft in the sky but, as others have pointed out, it\x92s not in any way appropriate in high traffic density environments. Just because there\x92s a rule that says you can do something doesn\x92t mean it\x92s necessarily a good idea.

Subjects ATC Separation (ALL) Visual Separation

Links are to this post in the relevant subject page so that this post can be seen in context.

2 recorded likes for this post.

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

YRP
February 04, 2025, 04:17:00 GMT
permalink Post: 11821110

Quote:

Originally Posted by framer

Yes you are right of course. My point was just whether he could tell whether he\x92d be turning the helo behind the traffic or into it when it might have passed in front. But as you say it was too low for a vector.

Subjects ATC Blackhawk (H-60)

Links are to this post in the relevant subject page so that this post can be seen in context.

No recorded likes for this post (could be before pprune supported 'likes').

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

21600HRS
February 04, 2025, 08:47:00 GMT
permalink Post: 11821199

Quote:

Originally Posted by galaxy flyer

Using visual separation, the system will generate CAs, they\x92re issued to alert the controller, not to provide guidance. Thats why the controllers ask, \x93do you have the traffic in sight?\x94

There is a problem in the system if you don\x92t react to CA. The visual avoidance should be aborted when the technically calculated separation is lost.

Subjects ATC Separation (ALL) Visual Separation

Links are to this post in the relevant subject page so that this post can be seen in context.

No recorded likes for this post (could be before pprune supported 'likes').

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

FullWings
February 04, 2025, 10:43:00 GMT
permalink Post: 11821285

Quote:

Originally Posted by 21600HRS

There is a problem in the system if you don\x92t react to CA. The visual avoidance should be aborted when the technically calculated separation is lost.

I think the issue is there are no visual separation standards, only IFR ones. Conflict Alerting (ATC) and TCAS (aircraft) have yet another set of parameters they use in different ways. The most common reason visual separation is requested by either party is to reduce separation below 1,000\x92/500\x92, 1.5, 2, 3, 5 miles or whatever is appropriate to the categories of airspace, aircraft and flights.

This means the automated tools (which don\x92t know the aircraft are using visual means to deconflict) will go off based on a predicted or actual loss of the separation criteria that they\x92ve been programmed with. If the helicopter in this instance had passed 1/4m behind and below the CRJ, a CA may still have been generated although the conflict had been resolved visually. The controller actually picks up on the apparent proximity and queries the heli that they are still visual, to which they reply in the affirmative - there is no minimum separation for visual avoidance, just sometimes it\x92s too dang close. Which is an Airprox.

Subjects ATC CRJ IFR Separation (ALL) TCAS (All) Visual Separation

Links are to this post in the relevant subject page so that this post can be seen in context.

4 recorded likes for this post.

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

Someone Somewhere
February 04, 2025, 10:52:00 GMT
permalink Post: 11821295

Quote:

Originally Posted by 21600HRS

There is a problem in the system if you don’t react to CA. The visual avoidance should be aborted when the technically calculated separation is lost.

The issue here, I believe, is that there's different standards for visual separation vs radar separation. A separation that results in a CA from the radar may still be entirely legal and acceptable. It's like trying to work out if two cars at an intersection will crash into each other from their GPS trackers: the data just isn't good enough and you don't know if one car will actually stop at the stop sign at the last second.

Radar orders also need to be given and actions taken sooner than if the crews are doing it of their own initiative. So a radar CA needs to be visible say 15 second pre-collision so ATC can wait for the radio to be clear then order pilots to manoeuvre. Pilots can aim to cross visually at more like 5 seconds.

I'm not saying that this is overall a good idea, but the fundamental reason you fit more planes in with visual separation is that you can put them closer together with (given good visibility) not too dissimilar safety.

[Edit: too late... Fullwings got this.]

Quote:

Originally Posted by 21600HRS

Quote:

]4) TCAS RAs on approach? you mean below 1000 ft ? No , in our scenario here , with the Blackhawk climbing , the logical RA would be a descent RA for the CRJ ,, you want a Descent RA at 300 ft ?

I think there is no problem for RA below 1000ft, it would only be like ”TRAFFIC AHEAD, PULL UP” in Airbus World. Horizontal separation might be smaller and system takes into account whether the traffic is between you and touch down. This DCA case is problematic because you join the final below 500ft, that is not acceptable in any case with an airliner.

TCAS 8 is getting closer and sooner after this horrific accident.

One aircraft gets a PULL UP, the other gets a NO CLIMB. Ideally you would have each aircraft advertise how much altitude it can gain/lose in 5/10/15 seconds and make the decision based on that. It would also fix needing to turn to TA only after engine failure.

Subjects ATC Blackhawk (H-60) CRJ DCA Radar Separation (ALL) TCAS (All) TCAS RA Visual Separation

Links are to this post in the relevant subject page so that this post can be seen in context.

1 recorded likes for this post.

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

dukof
February 04, 2025, 10:57:00 GMT
permalink Post: 11821301

Quote:

Originally Posted by YRP

Quote:

Originally Posted by framer

To the contrary, you're legally obliged to..

Quote:

2-1-6 SAFETY ALERT
Issue a safety alert to an aircraft if you are aware the aircraft is in a position/altitude that, in your judgment, places it in unsafe proximity to terrain, obstructions, or other aircraft. Once the pilot informs you action is being taken to resolve the situation, you may discontinue the issuance of further alerts. Do not assume that because someone else has responsibility for the aircraft that the unsafe situation has been observed and the safety alert issued; inform the appropriate controller.

NOTE-
1. The issuance of a safety alert is a first priority (see paragraph 2-1-2, Duty Priority) once the controller observes and recognizes a situation of unsafe aircraft proximity to terrain, obstacles, or other aircraft. Conditions, such as workload, traffic volume, the quality/limitations of the radar system, and the available lead time to react are factors in determining whether it is reasonable for the controller to observe and recognize such situations. While a controller cannot see immediately the development of every situation where a safety alert must be issued, the controller must remain vigilant for such situations and issue a safety alert when the situation is recognized.
Recognition of situations of unsafe proximity may result from MSAW/E-MSAW, automatic altitude readouts, Conflict/Mode C Intruder Alert, observations on a PAR scope, or pilot reports.
Once the alert is issued, it is solely the pilot's prerogative to determine what course of action, if any, will be taken.

...
b. Aircraft Conflict/Mode C Intruder Alert. Immediately issue/initiate an alert to an aircraft if you are aware of another aircraft at an altitude that you believe places them in unsafe proximity. If feasible, offer the pilot an alternate course of action. When an alternate course of action is given, end the transmission with the word \x93immediately.\x94

PHRASEOLOGY-

TRAFFIC ALERT (call sign) (position of aircraft) ADVISE YOU TURN LEFT/RIGHT (heading),
and/or
CLIMB/DESCEND (specific altitude if appropriate) IMMEDIATELY.

EXAMPLE-
\x93Traffic Alert, Cessna Three Four Juliett, 12'o clock, 1 mile advise you turn left immediately.\x94
or
\x93Traffic Alert, Cessna Three-Four Juliett, 12'o clock, 1 mile advise you turn left and climb immediately.\x94

...

Subjects ATC Blackhawk (H-60) Radar

Links are to this post in the relevant subject page so that this post can be seen in context.

1 recorded likes for this post.

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

Easy Street
February 04, 2025, 11:51:00 GMT
permalink Post: 11821345

Quote:

Originally Posted by mechpowi

Conclusion is that it\x92s unlikely that the NVGs on board signifitically affeted the crew\x92s ability to spot the conflicting traffic.

Sorry, that's nonsense (fixed wing military NVG experience here). It is true to say that NVG can be raised and lowered as required to alternate between aided and unaided search, but it does not mean that lookout is unaffected. Whenever the NVG are lowered, there are two large objects almost completely obscuring unaided vision and drawing focus to the eyepiece displays. Deliberate, conscious action is required to move the head to expand the aided search area beyond the static field of view. It is exceptionally easy to be deceived by lack of depth perception in NVG, and resolving differences between the aided and unaided pictures consumes mental capacity during the transition between modes. A NVG-only or mixed mode search would most certainly have reduced the helo crew's unaided search time, and therefore their probability of picking up the CRJ in peripheral vision to their left.

Among the many risky things I used to do as a military pilot, including diving towards the ground at 45 degrees in pitch darkness and pulling out on a range cue to miss the ground by 500 feet, one thing which always made the chain of command particularly nervous was closed pattern work on NVG. At home base, only experienced pilots were allowed to wear NVG in the pattern with another aircraft, and even then only one other: their similarly experienced formation wingman. And that was at a remote airfield with only a few military lives at stake and a tower controller monitoring both aircraft like a hawk. In Afghanistan, it was a toss-up whether the most dangerous place to fly fixed wing was over the Taliban or in the closed pattern at Kandahar, with helicopters darting around wearing covert lighting (they of course had an understandably different view of the risks). The idea of flying through the traffic pattern at a busy civilian airport using NVG to avoid airliners simply appals me.

Last edited by Easy Street; 4th February 2025 at 12:25 .

Subjects ATC CRJ Night Vision Goggles (NVG)

Links are to this post in the relevant subject page so that this post can be seen in context.

14 recorded likes for this post.

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

island_airphoto
February 04, 2025, 11:56:00 GMT
permalink Post: 11821350

Quote:

Originally Posted by ATC Watcher

Allow me few comments based on a long experience with TCAS evaluation et deployment .

The only solution I personally see is airspace segregation based on equipment . Class A, B and C restricted to aircraft carrying ADS-B out and TCAS equipped , and both Working and on the MEL as no go item s ( not the case today ) Waiting for AOPA and ATA remarks

i thought ADS-B was already required for Class B or under it. It certainly is for DCA. No way are you convincing anyone to put TCAS in a C-150 when they already ponied up for ADS-B.

Subjects ADSB (All) ADSB Out ATC DCA TCAS (All)

Links are to this post in the relevant subject page so that this post can be seen in context.

No recorded likes for this post (could be before pprune supported 'likes').

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

galaxy flyer
February 04, 2025, 13:02:00 GMT
permalink Post: 11821410

Quote:

Originally Posted by 21600HRS

There is a problem in the system if you don\x92t react to CA. The visual avoidance should be aborted when the technically calculated separation is lost.

Its VISUAL separation by the pilots, the controller did react, \x93PAT 25, do you have the traffic in sight?\x94

Subjects ATC Separation (ALL)

Links are to this post in the relevant subject page so that this post can be seen in context.

4 recorded likes for this post.

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

island_airphoto
February 04, 2025, 13:17:00 GMT
permalink Post: 11821423

Quote:

Originally Posted by ATC Watcher

I was taking Military , and here in DC airspace Class B you had one aircraft without ADS-B. out.( not that it would have changed anything ,) but if you want to devise /create a performant CAS using ADS-B it starts there .
Then there is the question of the C150s, you raised , of course no TCAS, we are talking ADS-B out, but even then, do you really want to have them anywhere near the approach path of a major busy airport airspace to start with ?

The military somehow exempted themselves with the results we see now.
I was a frequent visitor to DCA in C-150s and C-172s pre 9-11, it was a nice way to get to the city for dinner from the island I live on. Unless the airlines start buying their own private airports there is no sorting out of airplanes like that, public airports are for everyone with an airplane (9-11 bullcrap excepted). They would do "river tours" back then too, you got a trip up and down the Potomac with some great sightseeing. Back then airplane ramp fees were less than you could end up paying to park a car

Subjects ADSB (All) ADSB Out ATC DCA TCAS (All)

Links are to this post in the relevant subject page so that this post can be seen in context.

2 recorded likes for this post.

Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

Posts about: "ATC" [Posts: 614 Page: 15 of 31]¶