Originally Posted by
mabg88
Hello,
Is the curvature of the Earth used for this calculations?
mabg
Hi Mabg
Generally earth curvature isn't considered within PANS-OPS unless you are creating an ILS approach with a final approach segment longer than about 5NM. There are tables included in PANS-OPS Volume II which give the height above threshold at various distances, whilst taking account of curvature of the Earth and an RDH of 49 ft:
Additionally, PANS-OPS includes this formula:
Note, the 'D2' in the SI units should be 'D squared' (the same as the Non-SI formula) and these formulae are for a quadratic equation i.e. for a parabola, so will be for a parabola that approximates the curvature of the Earth's surface over 'intermediate distances'.
Hope that helps
Cheers
TeeS