Originally Posted by
InSoMnIaC
Some here must be quite happy to fly into terrain as long as they can quote the relevant AMC when asked at the pearly gates.
I came from the same team, but is this not below the waistline?
- If there is no obstacle, then there is no nothing to hit.
- If there is one, or essential terrain, it would be properly taken in an account in the OCA/H value, calculated down to the low limits of the temperature bracket for a "lowest denominator pilot" i.e. uncompensated flight.
With the two in mind
Should you raise the (D/M)DA for an uncompensated, flattened profile, you move the point of decision further from the THR and that
- invalidates your RVR minima values
- makes it harder or less likely to achieve the required visual reference in inclement weather (and uncovers vulnerability to get-homeitis)
- achieves no geometrical purpose in the terms of terrain clearance, since the underlying OCA has been calculated with a non-corrected altimeter in mind.
Simpler is safer, assuming the math has been done. The AMC achieves both goals.
At the same time,
172_driver shows a nice case where simple=safer has them do it the old way, while
Sepp above explains the how to get it approved.
What are the loose ends?