I don't suppose this MIA information is avaliable or published
somewhere is it? It would be useful for flight planning.

--Dan



Sam Spade wrote:
Dan wrote:

There are some places on IFR enroute charts where the OROCA (Off-route
obstruction clearance altitude) is actually lower than MEAs on an
airway in the same quadrant. The higher MEA is NOT due to obstacles in
adjacent quadrants.

If I'm on the airway, usually they don't let folks go down to the MOCA,
however if I file direct off-airways, how likely am I to be able to get
the ORCA? The goal is trying to stay below oxygen altitudes in
mountainous terrain while remaining IFR.

--Dan

When you go off-route the center will use is minimum instrument altitude
(MIA) chart. ATC will not use ORCAs; those are a concept that never
went anywhere other than to provide you with some information for
emergency or lost comm use.

Also, you can run into issues if you try to go direct through one of
those many chunks of Class G airspace in the western part of the country.