Gps Landing Systems

[ATCO17]

Has anyone had any experience of GPS Landing Systems? I know they're used at some airfields in the US and several other countries. Wondered what the CAA/NATS issues would be to their introduction in the UK.

[360BakTrak]

I believe the CAA are conducting small scale trials at a few airfields so who knows.............:confused:

[ATCO17]

Don't suppose you know where? Been asked to investigate an alternative approach system for my airfield. ILS is no good 'cos of airspace restrictions. Can conduct PAR and SRA, but many foreign aircrew don't seem too familiar with those approaches.

[055166k]

Give us a few more details if able, maybe some ideas will appear.
Have you approached the CAA for advice? They are unbelievably helpful.
What are the airspace restrictions that are causing a problem?

Would have thought most aircrew less familiar with GPS approaches than SRA, which is a recognised procedure with published approach plates; check out www.ais.org.uk

Don't know the level and detail required for a response as you only registered yesterday! Hope you aren't trying to make up a D-I-Y GPS approach....other than that ....ask away. Lots of examples of GPS approach plates available.
Kind Regards.

[ATCO17]

Still knocking a few ideas about at the moment. Did look at the Transponder Landing System. Seems like a cracking piece of kit but expensive. The military are all going across to JPALS in several years' time, which is a GPS based system, but looking for something sooner. Have a dog legged approach to the non-instrument runway here due to LHR, so ILS is unsuitable. Most inbounds are gucci biz-jets so most of them are GPS equipped. Don't worry, there'll be plenty of work going into planning of procedures, acqusition and sustainment etc.

[Scott Voigt]

ATCO 17... If you have good enough GPS coverage for your airfield then GPS is the way to go to get GOOD instrument coverage into your airport for folks who are GPS equipped. It is dirt cheap for the airfield too other than to have the appropriate instrument markings on the runway as well as having the appropriate field lighting.

A GPS approach will give you normal non precision minimums into the airport and you can make it pretty much however you want to go around other airports or obstacles, or you can go with the standard T arrangement as we use here. If you go with WAAS then you can get the GPS approach down to almost cat 1 ILS minimums 250/.5 mile and it will give you both course guidance and vertical guidance. It is quite nice. The only kicker to all of this is that you must have an approach rated GPS in the aircraft, but again for the airfield that is NO cost and only to that of the pilot. In the US we are getting more and more aircraft so equipped, in fact most of the new aircraft coming off the assemly lines are coming with IFR WAAS GPS's as standard equipment in an IFR package.

AOPA has this to say on their web site...

http://www.aopa.org/whatsnew/air_traffic/waas.html

If you have any further questions please feel free to ask. As to the TLS, NATCA has looked at it for the last few years and has been less than impressed with it. You can contact NATCA for how they feel about it...

regards

Scott

[Bith69]

What about RNAV (RNP) approaches? They'll all the rage down under.

[03Rnow30R]

Have a look at the Dubai plates. EK have been doing GPS approaches for over a year here in Dubai. They are quite handy when all the other toys go bang. Simple to use and you can almost treat them like a straight in ILS. Some pilots do prefer to slow down a little earlier on the approach though, but it doesn't pose any problems. Hope that helps.:O

[Scott Voigt]

Bith;

RNP is fine if you can afford the toys to play with. It is not at all cheap, where as GPS is pretty affordable for most GA ops..

regards

Scott

[Downwind.Maddl-Land]

ATCO 17 - I may be able to assist. Check your Personal Mesages.

[604guy]

Been doing GPS approaches in Canada for a decade now. With 2 more WAAS transmitters coming online in 2007 much of the southern half of the country will have limits to 250 ft. Without WAAS you can still get limits as low as 300 ft depending on local terrain/conditions. GPS will allow for some pretty good all weather access to airports where it would be economically unreasonable to consider expensive terrestrial hardware.

[ATCO17]

Thanks for the info everybody. As I said, still early days. Don't know if we yet have any WAAS or LAAS coverage in the UK as yet. Think I read somewhere that there are plans afoot to establish the European version for Heathrow in the near future. I know that Honeywell are a supplier of the ground stations, but having trouble contacting them on their website.

[chevvron]

I could say the answer for your airfield would be MLS, which would provide precision track guidance for curved or offset approaches, the problem being few systems in europe are operational enough for an evaluation (most bizjets carry 'multi-mode receivers' capable of receiving MLS signals though).
My airfield did install and evaluate TLS, which would be able to replicate your 'dogleg' appraoch; it wouldn't have worked out too expensive and the US Dof D were willing to 'chip-in' if it was installed.
Drawbacks were as it needs a unique transpoder code, it will only handle one aircraft at a time; you will then need the first aircraft to either go to standby or input a new code in the receiver before it will give info to the second. Another drawback was the transmitted signal was very weak compared to ILS on the same frequency. Also the CAA said it could take 'up to' 5 years to evaluate it before they would approve it!
At the moment, I think you'll find GPS is a non-starter, (but watch this space) until there is good enough LAAS coverage due to the fact the signals are very weak, and tend to attenuate as you get lower due to satellites getting closer to the horizon as the aircraft descends; all other systems mean the aircraft is approaching the transmitter thus the signal should get stronger the lower you are.

[bookworm]

Has anyone had any experience of GPS Landing Systems?

Are you talking about precision or non-precision approaches here?

[chevvron]

Bookworm he specifically mentions ILS and PAR so I would have thought that was obvious.

[bookworm]

Bookworm he specifically mentions ILS and PAR so I would have thought that was obvious.

ATCO17 wrote:

Can conduct PAR and SRA...

??

Last time I looked, SRA was non-precision.