On some non-precision approach plates, there is a VDA/TCH mark. My understanding of it is information-only. If you pass its starting fix at the charted altitude and maintain the given descent angle, the airplane will flying over the runway thresh hold at TCH.
However, I noticed one NOTAM mentions this information is not authorized, e.g. E16 RNAV (GPS) RWY 32 (on Nov 2019).
!FDC 9/9659 E16 IAP SAN MARTIN, San Martin, CA. RNAV (GPS) RWY 32, ORIG-C... GELVY TO RW32: 3.37/45 NA. 1903201729-2103201728EST - (From FAA website on 2019/11/22)
Given "GELVY TO RW32: 3.37/45" is still one spatial path for the non-precision approach, and the LNAV approach is still available. There are no airport elevation and re-defined fix height. So my questions align with,
1) Why am I not authorized to fly "GELVY TO RW32: 3.37/45", if my airplane is capable to maintain descent angle and have runway environment in sight right above MDA.
2) Are there any additional procedures to follow even for flying VDA/TCH at an airport when are authorized?