RNAV non-precision 3 (refer to 2)

28.10.2004

Answer or Commentary:

This seems to be Terps creeping into the camp. Terps has always dealt with turn areas as a constant turning radius for containment while Pans-Ops adopted the more complex wind spiral approach.
As an aside it is interesting to note how Mr Puskarica of New Zealand showed that a lesser protection area is achieved using a wind spiral (Archived discussions GPS missed approach 2)

As I said in the explanation previously it is very tempting to just join the areas on the outside of the turnwith a constant radius arc. However to be consistent with other parts of Pans-Ops one should use a wind spiral when turning over the FAWP. As far as I can see this is a judgement call on your part as a procedure specialist.

b)/2) Quite possibly you are correct and aircraft will not use a 25 deg. Bank for such a small turn but where do you draw the line? What is the definition of a small turn (all jokes in good taste will be posted)?

If definite data about bank angles verses course change in flight management systems was available perhaps this area of procedure design could be quantified and taken up with the ICAO obstacle clearance panel.

I.W.