Posts about: "Radar" [Posts: 135 Page: 5 of 7]ΒΆ

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Someone Somewhere
February 07, 2025, 18:15:00 GMT
permalink Post: 11823828
Originally Posted by JohnDixson
But, S-S, if the two flying machines we are discussing were under radar control, the accident would not have occurred.
Radar can absolutely fly two planes directly into each other. You have to put a number on how far apart they should be. If you call it "controller's judgement" then all you've done is change who's responsible, given that aircraft are never going to stick exactly to their assigned altitude and heading, and neither radar nor ADS-B gives exactly accurate positions, speeds, or headings.

This page, section "Separation minima based on ATS surveillance systems" quotes ICAO as saying that even in terminal space with good radar, separation should not go below 1,000ft vertically or 3Nm (2.5Nm if established on the same final approach in sequence within 10Nm of the runway). We're already blithely discussing half those standards as being impossible to meet.

Subjects ADSB (All)  ICAO  Radar  Separation (ALL)

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West Coast
February 07, 2025, 18:22:00 GMT
permalink Post: 11823829
Originally Posted by Someone Somewhere
Radar can absolutely fly two planes directly into each other. You have to put a number on how far apart they should be. If you call it "controller's judgement" then all you've done is change who's responsible, given that aircraft are never going to stick exactly to their assigned altitude and heading, and neither radar nor ADS-B gives exactly accurate positions, speeds, or headings.

This page, section "Separation minima based on ATS surveillance systems" quotes ICAO as saying that even in terminal space with good radar, separation should not go below 1,000ft vertically or 3Nm (2.5Nm if established on the same final approach in sequence within 10Nm of the runway). We're already blithely discussing half those standards as being impossible to meet.

Trying to understand the point you\x92re pushing. Are you of the belief that in terminal airspace (Class B in this case) that some minimum lateral or vertical separation standard must be applied? Apologies if I\x92m off base.




Subjects ADSB (All)  ICAO  Radar  Separation (ALL)  Vertical Separation

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Someone Somewhere
February 07, 2025, 21:37:00 GMT
permalink Post: 11823944
Originally Posted by West Coast
The guiding document in the US is the controller handbook, FAA order 7110.65AA. There, it is clear that visual separation is an approved form of separation in Class B airspace. Not defending the application of it specific to this crash, just pointing it out so the discussion revolves around existing FAA separation standards and not what folks in the thread wish it to be, believe it to be or what it is in their country.
Yes. My point is that if visual is deemed not acceptable, the next step appears to be several Nm. If you are telling the controller to keep them clear, they can't be just missed ; they need to actually be properly radar separated.

This is following on from #960-964, discussing what would happen if the PAT flight(s) refused visual separation. It seems like it would throw a spanner in ATC's arrivals and they would probably get a response similar to that Lufthansa A380: Buzz off somewhere else.

Subjects ATC  FAA  Radar  Separation (ALL)  Visual Separation

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West Coast
February 07, 2025, 22:59:00 GMT
permalink Post: 11824002
Originally Posted by Stagformation
To be specific, para 7.9.4b of the handbook, here:
https://www.faa.gov/documentLibrary/...5-24_READY.pdf

As mentioned upthread, if not visually separated then either 500ft or 1.5mi applies.

Correct if this is all wrong, but in the accident sequence if the helo had responded \x91not visual yet, looking\x92 or words to that effect, then presumably a controller could allow the two to get a bit closer and then advise the conflicting traffic info to the helo again, say at 2.5mi. If helo visual, great \x97maintain visual separation, responsibly passes to helo.

This is what happened, although the very busy controller failed to re-state the position of the CRJ to direct the eyes of the helo crew onto the CRJ in order that they could actually see and avoid it.

However if not visual at say 2.5mi, well it\x92s a bit late, but the controller does still retain responsibility for separation and must apply the 500ft/1.5mi standard. Presumably instant vectors away while simultaneously climb to min vectoring altitude. Or the CRJ has to go around. Can of worms in busy airspace\x97 helos and /or jets being dispersed all over the sky.

Much better to do a rules based system and mutually exclude intersecting IFR app/deps and Helo Visual Routes.
I will not speculate specific to the accident. One more point to add about visual sep then you guys can go back to arguing about the accident. Visual separation isn\x92t just applied aircraft to aircraft. The local controller can observe both aircraft, (even if they don\x92t see each other) and apply visual separation. Such as two aircraft that are diverging but radar separation isn\x92t established.

Subjects ATC  CRJ  IFR  Radar  See and Avoid  Separation (ALL)  Visual Separation

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SINGAPURCANAC
February 08, 2025, 06:22:00 GMT
permalink Post: 11824114
Originally Posted by Stagformation
To be specific, para 7.9.4b of the handbook, here:
https://www.faa.gov/documentLibrary/...5-24_READY.pdf

As mentioned upthread, if not visually separated then either 500ft or 1.5mi applies.

Correct if this is all wrong, but in the accident sequence if the helo had responded \x91not visual yet, looking\x92 or words to that effect, then presumably a controller could allow the two to get a bit closer and then advise the conflicting traffic info to the helo again, say at 2.5mi. If helo visual, great \x97maintain visual separation, responsibly passes to helo.

This is what happened, although the very busy controller failed to re-state the position of the CRJ to direct the eyes of the helo crew onto the CRJ in order that they could actually see and avoid it.

However if not visual at say 2.5mi, well it\x92s a bit late, but the controller does still retain responsibility for separation and must apply the 500ft/1.5mi standard. Presumably instant vectors away while simultaneously climb to min vectoring altitude. Or the CRJ has to go around. Can of worms in busy airspace\x97 helos and /or jets being dispersed all over the sky.

Much better to do a rules based system and mutually exclude intersecting IFR app/deps and Helo Visual Routes.
Could someone explain, how Twr ATCO in that particular enviroment, achieve required separation?
He is not radar qualified- so no headings or radar measurment distances applicable.
Where is prescribed what point is 1,5 Nm away from visual app for rwy 33? ( Note : Atco must achive required separation before that point)
or
At what point should be givem climb instruction for He to be 500' above arriving a/c before compromising 1,5Nm. If rate of climb is 1000 ft/min Helicopet need to climb for 40-50 seconds with the speed 180km/h it is 2 Nm or so - it means that instruction to climb should be given no latter than 4Nm from crossing point.
What is possibikity to spot particular aircraft for visual separation at distances more than 4Nm from crosssing points, duting the night and in bussy traffic enviroment?

Yes , I know it is Burund....

Subjects ATC  ATCO  CRJ  IFR  Radar  See and Avoid  Separation (ALL)  Visual Separation

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Stagformation
February 08, 2025, 11:52:00 GMT
permalink Post: 11824286
Originally Posted by West Coast
Visual separation isn\x92t just applied aircraft to aircraft. The local controller can observe both aircraft, (even if they don\x92t see each other) and apply visual separation. Such as two aircraft that are diverging but radar separation isn\x92t established.
That\x92s absolutely right. If the controller takes a look outside, identifies the correct aircraft and sees that their lights (at night) are diverging then all is ok, separation assured.

In this case though the aircraft lights were rapidly converging, the radar repeater was flashing \x91CA\x92 but the helo has already requested and been given responsibility for collision responsibility. Crazy tragic situation.

Subjects ATC  Radar  Separation (ALL)  Visual Separation

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DaveJ75
February 08, 2025, 14:30:00 GMT
permalink Post: 11824387
Originally Posted by West Coast
Visual separation isn\x92t just applied aircraft to aircraft. The local controller can observe both aircraft, (even if they don\x92t see each other) and apply visual separation. Such as two aircraft that are diverging but radar separation isn\x92t established.
I keep re-reading this and it doesn't get any less amazing! To hell with the radar, I'll just look out of the window!

I would love to see it tried - obviously it would have to be over the desert in aircraft with no pax aboard! How would it work - do you just yell " Bloggs, left a bit " over the RT if all looks a bit close?

Subjects ATC  Radar  Separation (ALL)  Visual Separation

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West Coast
February 08, 2025, 16:17:00 GMT
permalink Post: 11824431
Originally Posted by DaveJ75
I keep re-reading this and it doesn't get any less amazing! To hell with the radar, I'll just look out of the window!

I would love to see it tried - obviously it would have to be over the desert in aircraft with no pax aboard! How would it work - do you just yell " Bloggs, left a bit " over the RT if all looks a bit close?
I will not speak to this accident but I will tell you as a controller I applied visual sep countless times over the years, all successfully.

Subjects ATC  Radar

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West Coast
February 08, 2025, 16:20:00 GMT
permalink Post: 11824433
Originally Posted by SINGAPURCANAC
Could someone explain, how Twr ATCO in that particular enviroment, achieve required separation?
He is not radar qualified- so no headings or radar measurment distances applicable.
Where is prescribed what point is 1,5 Nm away from visual app for rwy 33? ( Note : Atco must achive required separation before that point)
or
At what point should be givem climb instruction for He to be 500' above arriving a/c before compromising 1,5Nm. If rate of climb is 1000 ft/min Helicopet need to climb for 40-50 seconds with the speed 180km/h it is 2 Nm or so - it means that instruction to climb should be given no latter than 4Nm from crossing point.
What is possibikity to spot particular aircraft for visual separation at distances more than 4Nm from crosssing points, duting the night and in bussy traffic enviroment?

Yes , I know it is Burund....
How are you so sure the local controller isn\x92t as you put it \x93radar qualified\x94? I worked towers and issue vectors as needed.

Subjects ATC  ATCO  Radar  Separation (ALL)  Visual Separation

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Stagformation
February 08, 2025, 16:34:00 GMT
permalink Post: 11824442
Originally Posted by DaveJ75
I keep re-reading this and it doesn't get any less amazing! To hell with the radar, I'll just look out of the window!

I would love to see it tried - obviously it would have to be over the desert in aircraft with no pax aboard! How would it work - do you just yell " Bloggs, left a bit " over the RT if all looks a bit close?

It happens all day long at airfields. Controller sees and gives clearances, eg remain dead side, go around, hold short of the active, expedite etc.

Subjects ATC  Radar

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island_airphoto
February 08, 2025, 16:47:00 GMT
permalink Post: 11824451
Here you go: Read All About It.
https://www.avweb.com/flight-safety/tower-brites/
This explains the different phraseology between a tower using a BRITE to help out vs. the phraseology of tower certified and equipped for full radar separation. It also explains LOAs for airspace. Where I learned to fly at KMLB the tower only owned up to about 1800 feet IIRC and approach had above that. In those pre-BRITE days it helped a lot for handling IFR traffic.
( I sometimes flew a Bell 47 helicopter there and the tower managed to organize it such that I never came close to any airplanes)

Subjects IFR  Phraseology (ATC)  Radar  Separation (ALL)

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SINGAPURCANAC
February 08, 2025, 21:34:00 GMT
permalink Post: 11824590
Originally Posted by West Coast
How are you so sure the local controller isn\x92t as you put it \x93radar qualified\x94? I worked towers and issue vectors as needed .

there is no word IDENTIFIED b efore any other instruction.

It is esential basic for radar/ surveilance. How the hell you could give vectors for non identified aircraft?



And the above post of island_photo gives exact link with explanation that is officially valid in USA.
No full radar service if it is not " radar contact"( or identified)

It is so logic and simple to remember and to apply.


Last edited by SINGAPURCANAC; 8th February 2025 at 21:45 .

Subjects ATC  Radar

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Awol57
February 08, 2025, 22:30:00 GMT
permalink Post: 11824606
I would assume the US wouldn't be hugely dissimilar to to the USA in this regards, but a tower controller can
"Correlate an observed radar position symbol with manoeuvres currently
executed by a departing aircraft which acknowledged instructions to that
effect, provided that identification is established within 3 NM of the radar
sensor."

So identified on departure, and the usual transfer of Identification occurs for inbound. So no problems using a radar provided we meet the other requirements (MVA and the like). However the whole point of a tower controller is that we can use less than the radar standard and visually separate aircraft in visual conditions.

Subjects ATC  Radar

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West Coast
February 09, 2025, 01:47:00 GMT
permalink Post: 11824686
Originally Posted by Awol57
I would assume the US wouldn't be hugely dissimilar to to the USA in this regards, but a tower controller can
"Correlate an observed radar position symbol with manoeuvres currently
executed by a departing aircraft which acknowledged instructions to that
effect, provided that identification is established within 3 NM of the radar
sensor."

So identified on departure, and the usual transfer of Identification occurs for inbound. So no problems using a radar provided we meet the other requirements (MVA and the like). However the whole point of a tower controller is that we can use less than the radar standard and visually separate aircraft in visual conditions.





It\x92s been quite awhile since I was on that side of the microphone, but yes our operations are similar.

Subjects ATC  Radar

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West Coast
February 09, 2025, 01:50:00 GMT
permalink Post: 11824687
Originally Posted by SINGAPURCANAC
there is no word IDENTIFIED b efore any other instruction.

It is esential basic for radar/ surveilance. How the hell you could give vectors for non identified aircraft?



And the above post of island_photo gives exact link with explanation that is officially valid in USA.
No full radar service if it is not " radar contact"( or identified)

It is so logic and simple to remember and to apply.
Recall that your post said the controller wasn’t radar qualified, not that the helo was/wasn’t identified. Whether it was or wasn’t, I won’t speak to as I don’t know. What I do know is Local controllers (assuming trained and with appropriate equipment and mapping) can and often do provide vectors, I often did working local. Unsure why you’d make such a claim otherwise.

BTW, in the US, it’s not “identified” but rather radar contact.
Last edited by West Coast; 9th February 2025 at 02:49 . Reason: Spelling

Subjects ATC  Radar

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cbradio
February 09, 2025, 11:33:00 GMT
permalink Post: 11824877
Originally Posted by Awol57
However the whole point of a tower controller is that we can use less than the radar standard and visually separate aircraft in visual conditions.
This.

Subjects ATC  Radar

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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
Originally Posted by ATC Watcher
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..
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
(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
Originally Posted by ATC Watcher
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..
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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YRP
February 09, 2025, 20:32:00 GMT
permalink Post: 11825106
Originally Posted by ATC Watcher
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..
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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