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manoliss
2nd Nov 2010, 13:29
Hello everyone

I am a French air traffic controller (nobody's perfect:O) and a newcomer on PPrune. I am currently working on the deployment of LPV approachs in France.
I am looking for details about the procedures followed in case you lose GPS signal during final approach especially in the States where LPV are already in use with WAAS. I know they are not published and developed by every airline.
Are they the same in case of ILS failure?

Thank you for your help

aterpster
2nd Nov 2010, 14:23
If an ILS fails the missed approach may be predicated on VOR. So, no big deal.

LPV is no different than any other RNAV instrument approach procedure (IAP) when it comes to a GPS failure. Guidance is gone (unless the aircraft is a high-end bird with IRUs). If radar services are available they are the backup. In a non-radar area the pilot has no choice but to dead reckon along the missed approach course (or courses) to the best of his ability. At some point VOR reception should occur (well, at least for now).

Pre-SBAS RNAV IAPs have been in wide use in the U.S. for 12 years, or so, with no loss of GPS yet, at least none that has been made public.

RNP AR is the exception, at least where RNP of less than 1.0 is used for the missed approach. In that case, the aircraft must have at least 1 IRU because the containment areas are too narrow for dead reckoning (or even radar vectors) in the event of a loss of GPS.

manoliss
2nd Nov 2010, 14:53
That's a clear answer. I thought there were procedures diverging from the missed approach. But it seems to be a myth.
Thank you