"John Hairell"
CASA 212s are used by both the USAF and Army. The Army has used them
for specialized ELINT/SIGINT and special ops. The Twin Otter may be a
three-letter agency bird. They are also still using C-47s for drop
work.

The Twin Otter was used for a couple of medical Antarctic rescue
missions in the dead of winter. The crews were from Edmonton Alberta. One
of the few aircraft capable of flying under these harsh conditions. Simple,
with less chance of freeze up etc.
Ed