Jim Carter wrote:


-----Original Message-----
From: Sam Spade ]
Posted At: Monday, August 07, 2006 8:27 AM
Posted To: rec.aviation.ifr
Conversation: CAT IIIC minimums
Subject: CAT IIIC minimums

Jim Carter wrote:


So contrary to what others have suggested, the NA does not mean "not
authorized"; rather, it means "not applicable".

Where do you get that idea? From an incorrectly printed Jepp chart
perhaps?

Check FAR 97.3, and I quote:

(n) "NA" means not authorized.


Please notice the quote I pasted from the TERPS manual. Also, please
read the notes on the pages I originally referenced. They state that
there is no applicable RVR (visibility) requirement for CAT IIIc. They
also state that CAT IIIc is operation with visibility unsuitable for
taxi.

How could an approach be authorized yet have the visibility requirements
part of it be not authorized? When you take that NACO plate into
consideration in light of the TERPS manual, not applicable is a
reasonable conclusion.

But, NA has a regulatory definition for Part 97 standard instrument
approach procedures. There is no provision for conjecture when NA is
issued under Part 97.

CAT IIIc is not authorized for any operator at the present time. The
concept is that it *may* be authorized at some future time, provided
something such as enhanced vision systems become good enough to taxi
without any visibility.

The FAA, being the way it is, had to have a building block of minima
that went "all the way" so to speak, when they implemented the Category
III program in the 1970s.

They like having goals, even unachievable goals. ;-)