G'day Bob and team !

Can you please through some light on solution of Q7 of CIR revision set Four .

You are tracking inbound to Ballarat from South for Ballarat RWY 36 RNAV Z prosecuted in VH-OZY . You intend to carry out the 3degree approach gradient as published on chart . the point at which you may commence descent from 4000 ft is :

C ) After passing BLZA and established on 288 M track to BLZSI.
D) 2.9 NM from BLZSF , the FF for approach .

Answer in solution key is C but I am also not able to understand why D is wrong and as in explanation it is mentioned that Min altitude from IAF is 2900 ft but it seems 2800ft to me ( please let me know if there is something wrong in my way of interpretation) .

As always , thank you so much for your time and help .

Regards
Sahil

The shaded areas below 2800ft are not part of the approach profile. They simply indicate the areas where terrain clearance cannot be assured. It was never intended that you fly level at 2800ft. If you inspect the distance/height table at the top, you will see that if you are going to do the 3° approach profile, you should remain not below 4000ft once you pass the initial approach fix and commence tracking 358° towards the final approach fix. From 4000ft, the 3° approach commences at 2.9nm from the final approach fix (7.9nm from the missed approach fix at the runway threshold). This gives you a chance to establish a stable approach to the runway.

It's not illegal to fly level at 2800ft on top of the shaded areas, but that's not the 3° approach profile the question required. It is also not the accepted method of flying the approach.

Thank you so much for detailed explanation Bob.

But I am still not convinced with answer D as we are starting the decent only at 2.9 NM from BLZS , the FF for approach ( D).

Can you please let me know how C is correct as we can't descent after BLZSA if we follow the approach plate .