The Future?

[nigelb]

A Satellite System That Could End Circling Above the Airport

http://tinyurl.com/7g9zpfw

Nigel²

[cstorey]

Sounds like nonsense to me . Alaska is one thing, Seattle is another , but neither are exactly the centre of the universe. There are 2 major constraints on traffic density . The first is the minimum spacing required to avoid wake encounters . The second is that there is an irreducible minimum time that a landed aircraft needs to be able to vacate the runway . Although I can remember at the end of my time in aviation receiving " land after" clearances at Heathrow ( usually on top of a minimum 160 knots instruction just to make it more hairy ) these merely served to illustrate just how dense the traffic is on the ground . Use of satellite technology cannot influence either of these factors

[Garry Russell]

That was my first thoughts too

Runway capacity will not be increased by this.

I even looked for a date

[Chris Trott]

NextGen just got its latest funding boost (actually, it's the first real funding of it ever) a couple months ago. The system is extremely promising and the technology is sound and actually has been pretty well tested even outside of Alaska. While it won't increase the actual runway capacity, it'll increase the approach capacity significantly because it'll eliminate the need for aircraft to be lined up 20+ miles out from the runway, instead being able to use predictive computer capability to plot each aircraft directly into its place in line and then communicate that information direct to the cockpit. Basically what it does is give a custom RNAV approach to every single airplane that is approaching a given airport so that they all arrive in the proper place at the proper time, allowing for the utilization of the runways to go up, which is where a lot of time is lost today because you have to build in "bubbles" around every airplane to allow for pilot reaction times and controller inaccuracies in giving vectors.

Full info is on the FAA's website - http://www.faa.gov/nextgen/

As for timeline, they've been targeting 2020 for full implementation at the major US airports and 2030 for nationwide NextGen.

[Garry Russell]

Airports where stacking takes place have the runways in continuous use, so this will make no difference in those cases.

[DaveB]

I've tried hard to get my pea sized brain around this and I'm having difficulty seeing how it will work at busy airports at peak times. A point will surely come when traffic on the ground will restrict what can land and as CS said.. there is always going to be turbulence separation too. The idea of what amounts to 'turning up' from any direction and having the computer slot you in can only work up to a point.. I'd have thought

ATB
DaveB

[Garry Russell]

Exactly Dave ...they land one after another with minimum separation and in fact go arrounds due to late clearing or catching up are quiet common.

At LHR for example there are several stacks on the go.

The approach can be seen as one after another stepping into the distance.

So I can't see what this is supposed to do

Seriously...my first impression was that it maybe an April Fool wind up...it's not, but I thought it was

[airboatr]

I even looked for a date

You can google a date these days, .... so I've been told.

[Garry Russell]

[Chris Trott]

The advantages come with the enroute and with the poor weather situations where utilization isn't optimized. A lot of the stacking in the US isn't due to overcapacity of runways, it's trying to sort out aircraft coming from many different directions onto the limited number of IFR approaches, especially in poor weather. This is where LHR's MLS system comes into its own and where it will work well for the US. Additionally, if you look at Europe and the RNAV arrivals, what they do there is similar to what will be done with the satellite system, but with the additional flexibility of modifying it reliably to have an aircraft arrive over a given point at the exact time required to maintain spacing.