Oceanic 5-minute along track trial

[Jeroen Hoppenbrouwers]

http://www.skybrary.aero/bookshelf/books/1201.pdf

The current longitudinal separation minimum applied in North Atlantic (NAT) airspace, for MNPS approved aircraft pairs on the same track, is 15 minutes which may be reduced to 10 minutes using the Mach number technique.

As part of a programme to improve service provision in NAT airspace, on 25 May 2010, a trial of a 5 minute along track longitudinal separation minimum will commence in the Shanwick OCA. Flight data processing limitations will delay Gander ACC participation until late 2010, the exact date for which will be indicated via AIC or NOTAM. The application of such a minimum is intended to aid the provision of optimum vertical profiles for those aircraft suitably equipped and is predicated on the use of ADS-C periodic reports which will provide ATC with increased confidence in aircraft position reports and estimates. Initially, the trial will only involve eastbound aircraft.

[ray]

Thanks Jeroen ... for the info
Sounds like RNP4 system requirements to me.

Raymond

[Zinger]

I'm curious as to how it was done. If Gander couldn't increase eastbound traffic density, how did Shanwick get that density for the test?

[Holger Wende]

I can think of two options:

Delayed (or brought forward) fligh level changes in the Shamwick area could congest aircraft such that a 5 min spacing is achieved on specific tracks and flight levels.

Additionally cancellation of speed restrictions could cause a reduced spacing between 2 or more aircraft (aircraft traffic jam).

Or are such options not practical in real life even if properly monitored through ADS-C?

[Zinger]

Typically one step climb would be requested for optimal performance, and to not allow it or to climb earlier than optimal costs operator money, similarly for descent. Same with cruise mach change. Nowadays while airlines barely make profit is not really a good idea, but possible. In any case, to change the flow to 5 minute gaps is not simple, within 2 hours of flight, even if all those means were used, and the airline pilots enthusiastic and cooperative. The impact in London, Paris, Amsterdam, Frankfurt etc... approach area should be interesting, arrivals typically early morning during heavy departure time.