Originally Posted by
RW20
TCAS FAN
You mention that the VOR DME life is coming to the end,this surely has an impact on approach aids especially with 20 which doesn't have RNav approach procedures,given that if the ILS is U/S what aid is available,and indeed 02 would have just Rnav approaches.
Stewy
The impact on RWY 20 IAP will be minimal for CAT C aircraft (E190/195, E145, A319/320, B737) when the plug is pulled on the VOR/DME.
Rather than bore you with the technical criteria for instrument approach procedure design, because of the offset location of the VOR/DME relative to the RWY 20 final approach track it is not possible to meet design criteria for an approach to the runway. Instead the current procedure is an approach to the airport, ie a cloud break procedure which (weather permitting) will permit visual manoeuvring onto the final approach track. Consequently the approach minima is relatively high (OCA 890 FT AMSL).
Until an RNAV approach is provided the only option for a CAT C aircraft, in order to get the lowest minima is an NDB/LOC IAP using the "EAS" NDB. This gives an OCA 510 FT AMSL, still more than double the current ILS minima (OCA 237 FT).
An RNAV approach will not (with current UK restrictions on use) match the ILS minima, however there could be an improvement on the current NDB/LOC minima.
An NDB/LOC IAP is available for RWY 02 if the RNAV IAP is not available,