Getting the MOCA

Everett M. Greene wrote:
Sam Spade writes:
[snip]

However, if both a MEA and a MOCA are prescribed for a particular route
or route segment, a person may operate an aircraft below the MEA down
to, but not below, the MOCA, when within 22 nautical miles of the VOR
concerned (based on the pilot's reasonable estimate of that distance).


Idle curiosity: From whence came the magic 22 nm. number?
The VOR turns into a pumpkin at 22.1 nm?

It is 25 s.m., which is 22 n.m.

I can only speculate that in the early days of VOR it became quickly
apparent that relief from the MEA when nearing a VOR on an airway with a
lower MOCA would provide better descent transitions onto IAPs, etc.

The feds probably had a meeting and asked the electronic experts to come
up with a distance that would work everywhere.

That's how things like that usually come about.