It would be fascinating to drill down on that old 6.9 degree clearance buffer and find out how the hell did it ever see the light of day?
What greater mind of middle ages thought that whilst one was drilling their way through a turbulent cloud mass that one could measure decimal points on the ADF.
What was so alien about the concept of a round number that had whoever locked into the mindset that it had to be 6.9 not 7.0 or better yet 10.
This alone is enough to take the entire legal workings from this department and throw the lot over ones shoulder and come up with your own rule based system.