Time based final approach spacing
Joined: Jan 2008
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From: The foot of Mt. Belzoni.
"2nm radar separation is being worked on within SESAR'
Interesting statement.
I was taught that en-route and approach radar radar separation minima were different due to the technical limitations of the equipment employed in those functions.
Area radar....50cm, or 23 cm radars, refreshing at 10rpm, required a separation 'minima' of 5nm. (10nm in azimuth outside of certain ranges from the radar source).
Approach radar....10cm equipment refreshing at about 15rpm, gave a separation 'minima' of 3nm.
What new equipment are SESAR mandating/installing which will allow this proposed reduction in radar separation minima, and therefore safety?
Interesting statement.
I was taught that en-route and approach radar radar separation minima were different due to the technical limitations of the equipment employed in those functions.
Area radar....50cm, or 23 cm radars, refreshing at 10rpm, required a separation 'minima' of 5nm. (10nm in azimuth outside of certain ranges from the radar source).
Approach radar....10cm equipment refreshing at about 15rpm, gave a separation 'minima' of 3nm.
What new equipment are SESAR mandating/installing which will allow this proposed reduction in radar separation minima, and therefore safety?
Joined: Oct 2004
Posts: 531
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From: Southern England
Multi-Static Primary Surveillance Radar, previously discussed on this forum, and Multi Lateration of the Mode S signal both have the potential to reduce separation standards primarily because they remove the restriction of a refresh rate based on how fast you can turn a heavy lump of metal.
Joined: Dec 1999
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From: LHR/EGLL
2nm MRS should be getting to V2 maturity in SEASR, not sure of the progress as I'm not directly involved. V2 is the feasbility stage, so effectively to develop a mature concept only.
I know that the project had identified technical and operational issues, among which, I assume, is the currency (update rate) of the surveillance picture. I assume also that the solution to this is muti-static and/or multi-lat. There's a lot of RF energy out there reflecting off aircraft.
edit: cross posted with eglnyt
I know that the project had identified technical and operational issues, among which, I assume, is the currency (update rate) of the surveillance picture. I assume also that the solution to this is muti-static and/or multi-lat. There's a lot of RF energy out there reflecting off aircraft.
edit: cross posted with eglnyt
Joined: Mar 2008
Posts: 148
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From: London
Hundreds of flight delays hit Heathrow
Hundreds of flight delays hit Heathrow
Hundreds of flights were delayed at Heathrow two days after a new system went live to 'cut delays caused by strong winds'.
The delays affected 287 flights taking off from Heathrow on Sunday and 288 flights arriving at the London airport, according the flight data website Flight Aware.
The new system, Time Based Separation (TBS), went live on Friday and was described as a 'world first'.
In a press release by NATS, it said: "A new way of separating arriving aircraft at Heathrow Airport by time instead of distance in order to cut delays caused by strong winds has gone live as part of a phased introduction this year.
"Traditionally, air traffic controllers separate flights by set distances dependent on the aircraft type and the size of the spiralling air turbulence - or wake vortex - they create as they fly.
"Time Based Separation (TBS) takes live wind data from the aircraft to dynamically calculate the optimal safe spacing between each aircraft in order to maintain the landing rate. Its introduction is expected to halve current headwind delays at the airport and significantly reduce the need for airlines to cancel flights."
A spokesman for Heathrow Airport said: "There were delays at Heathrow yesterday due to very high winds.
"We had no cancellations (out of the approximately 1300 scheduled flights) so although we are running at 98% capacity the airport coped well with the weather disruption.
"Of course we are sorry for those passengers who were delayed yesterday."
A spokesman for NATS said: "The tool is obviously new so it will take some time for us to be getting the absolute most out of it.
"We are currently in a period of Limited Operational Service to refine our processes and ensure everything is working as expected. We then plan to go fully live on 1 May, although further refinements will probably be made over the course of the year."
Monday, March 30, 2015
Hundreds of flights were delayed at Heathrow two days after a new system went live to 'cut delays caused by strong winds'.
The delays affected 287 flights taking off from Heathrow on Sunday and 288 flights arriving at the London airport, according the flight data website Flight Aware.
The new system, Time Based Separation (TBS), went live on Friday and was described as a 'world first'.
In a press release by NATS, it said: "A new way of separating arriving aircraft at Heathrow Airport by time instead of distance in order to cut delays caused by strong winds has gone live as part of a phased introduction this year.
"Traditionally, air traffic controllers separate flights by set distances dependent on the aircraft type and the size of the spiralling air turbulence - or wake vortex - they create as they fly.
"Time Based Separation (TBS) takes live wind data from the aircraft to dynamically calculate the optimal safe spacing between each aircraft in order to maintain the landing rate. Its introduction is expected to halve current headwind delays at the airport and significantly reduce the need for airlines to cancel flights."
A spokesman for Heathrow Airport said: "There were delays at Heathrow yesterday due to very high winds.
"We had no cancellations (out of the approximately 1300 scheduled flights) so although we are running at 98% capacity the airport coped well with the weather disruption.
"Of course we are sorry for those passengers who were delayed yesterday."
A spokesman for NATS said: "The tool is obviously new so it will take some time for us to be getting the absolute most out of it.
"We are currently in a period of Limited Operational Service to refine our processes and ensure everything is working as expected. We then plan to go fully live on 1 May, although further refinements will probably be made over the course of the year."
Monday, March 30, 2015
Joined: Jan 2008
Posts: 17,699
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From: Reading, UK
Interesting presentation this morning from NATS and Lockheed Martin. No real surprises, but some useful background on the trial and the experiences since it started on the 24th (at 15:05, to be precise, with the first aircraft handled being BAW14GM, an A319 from Linate).
The weekend, needless to say, saw the benefits start to kick in with the high winds, with separation distances being reduced in some cases by over 30%, eg a 5nm pair being spaced at 3.4nm in the 50-60kt winds and around a 6-7 landings per hour improvement compared to distance-based separation in the same conditions.
A recording of the presentation can be downloaded from here: Time Based Separation (registration required).
The weekend, needless to say, saw the benefits start to kick in with the high winds, with separation distances being reduced in some cases by over 30%, eg a 5nm pair being spaced at 3.4nm in the 50-60kt winds and around a 6-7 landings per hour improvement compared to distance-based separation in the same conditions.
A recording of the presentation can be downloaded from here: Time Based Separation (registration required).
Joined: Jan 2008
Posts: 17,699
Likes: 2,042
From: Reading, UK
Also now up on YouTube, for anyone who prefers to watch anonymously: https://www.youtube.com/watch?v=SD7zia4eF5o
Joined: Feb 2006
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From: Rapunzel's tower
Very informative....when will flow rates for strong winds be lifted I wonder? Evidence so far seems to suggest it should be soon 
I'm also very interested in when it could be applied to a single runway (mixed mode) operation. I can see that both distance-based-markers and time-based-markers (in the fullness of time!) would be of use to both the airport where I work and the approach unit. (In our case WTS is not such an issue in peak times as the mixed mode spacing is seldom less than WTS, however, it would provide a useful tool for consistency of spacing for approach control.)
I'm also very interested in when it could be applied to a single runway (mixed mode) operation. I can see that both distance-based-markers and time-based-markers (in the fullness of time!) would be of use to both the airport where I work and the approach unit. (In our case WTS is not such an issue in peak times as the mixed mode spacing is seldom less than WTS, however, it would provide a useful tool for consistency of spacing for approach control.)
Joined: Jul 2008
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From: Seaty Sea
Here's some NATS publicity about a first look at Time-Based Gaps for a single runway airport.
Building a shared picture for Tower and Approach | NATS Blog
Building a shared picture for Tower and Approach | NATS Blog
Thread Starter
Joined: Oct 2000
Posts: 8,266
Likes: 1
From: Berkshire, UK
<<Getting the most from a single runway needs great cooperation between the controllers in the tower and those working in approach to interweave arrivals and departures.>>
I think I have just come up with a winning idea... Why not have the approach and radar units at the airfields so that the controllers could have validations for TWR and APC? Wouldn't this give everyone a better understanding of the other side of the job? Expect somebody has already thought of that...
I think I have just come up with a winning idea... Why not have the approach and radar units at the airfields so that the controllers could have validations for TWR and APC? Wouldn't this give everyone a better understanding of the other side of the job? Expect somebody has already thought of that...
Joined: May 2000
Posts: 712
Likes: 17
From: SE England
Yep HD they're already a step ahead of you:-
Expect to see all of Heathrow done by one person in an industrial estate in Romania soon
- Radar in tower (one controller)
- Remote tower ops
- CPDLC replacing radio
Expect to see all of Heathrow done by one person in an industrial estate in Romania soon
Thread Starter
Joined: Oct 2000
Posts: 8,266
Likes: 1
From: Berkshire, UK
I love it! A bloke from one of the universities came to Heathrow donkey's years ago and said he was looking into automating the set-up, apparently at the behest of CAA. I told him he'd be better employed finding a better way to sort out the EG list. Didn't go down too well with some be-suited people!
Joined: Jan 2008
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From: The foot of Mt. Belzoni.
HD and Dan,
brilliant.
This has moved on a bit since I last looked.
Also, why not put the area control centres near to the airports too?...Then, airport and en-route staff could visit each other's places of work to see what happens. It might create a spirit of 'team-building'. Also, 'Pilots'.......Who are the 'End-users'.....Er, sorry....'Customers', of the services provided, could easily visit all sides of ATC to see what's going on?
brilliant.
This has moved on a bit since I last looked.
Also, why not put the area control centres near to the airports too?...Then, airport and en-route staff could visit each other's places of work to see what happens. It might create a spirit of 'team-building'. Also, 'Pilots'.......Who are the 'End-users'.....Er, sorry....'Customers', of the services provided, could easily visit all sides of ATC to see what's going on?
Last edited by ZOOKER; 8th April 2015 at 21:37.
