Anyone wishing to find the list of backup network naiads, look on the CASA website and find reference to a NPRM1105AS for aircraft equipage. Annex G gives a list of the navaids which will be kept after the mandate date of Feb 2016.
This list was put together by ASTRA. Look this up too; it is a consultative body made up of various members of the aviation fraternity, including QANTAS, Virgin, AOPA, RAAA etc. This body reports to the APG which is basically a coffee club of the CEO's of AsA, CASA, DoIT and Defence. APG recommends to the Ministers of Defence and Transport.
The list was formulated in 2005 and has been accepted by all these bodies. The reasoning behind the list: it is a backup in case of GPS failure and is supposed to provide guidance to the nearest suitable aerodrome - note most suitable and not preferred aerodrome. Currently there are approximately 410 non precision aids (NDB, VOR, DME). There are about 220 on the backup list. The declared position of both CASA and Airservices is that there will be a reduction to the backup network after the mandate kicks in in Feb 2016. This is easily determined by looking at published 5 and 10 year plans on the various websites.
AsA has been decommissioning aids since the 1990's on a site by site determined basis. There are a large number of aids which were commissioned in the 60's and 70's which have either outlived their original purpose or have become difficult to maintain - spares, structures, electronics, suppliers, any number of reasons. This will continue to occur. There are sites under scrutiny now as anyone who has attended a recent RAPAC can attest.
The bare facts are that it costs around 600K to replace an NDB and around 1.2mill to replace a VOR. A DME not so much because the antenna and electronic setups are simpler. The big players in aviation are not prepared to pay for this replacement in the long run when they are equipping to run GNSS nav system. ASTRA was told in 2005 that to replace the ground based nav system outside of the backup network would cost between 140 and 200 million dollars. You can do the sums for the current cost.
Last edited by Robbovic; 2nd Jun 2012 at 06:08.