Reviving an old thread.
The 2 Mar 2017 revision to AIP has removed Para 1.11 which started this off:
DAP-Reference
1.11 -AIP ENR 1.5 para 5.3.3 advises that "Where the forecast area QNH is used, the minima used must be increased by 50FT".
All ASA instrument approach procedures include this adjustment where a regular TAF service is not available(AIP GEN 3.5 para 16). No adjustment is necessary to meet the requirement of AIP for those aerodromes.
When an aerodrome receives a regular TAF service and the TAF is not available the AlP paragraph is applicable.
There is a subtle change bar with a
D.
I asked ASA about this and they advised that CASA had requested that charts in the DAP (and hence Jeppesen) Effective 2 MAR 2017 don't include an extra 50ft in accordance with AIP ENR 1.5 par 5.3.4.
However ...the charts in question at any port that does not receive a TAF have not been revised to remove the 50ft
So in accordance the aforementioned AIP Enroute ref we have to add 50ft to the published minima even though the data already includes it!
I was advised that "cyclical maintenance" would reduce the minima ...so expect another raft of revisions. Until then we are much safer being that much higher above the hard bits
Just catching up with Worlds Best Practice I guess.