Originally Posted by
Cubdriver
An airline pilot may wish to comment on this because they fly only IFR and would know more about real world practices; but I think if you are cleared to intercept a particular DME arc by a controller then you may do so, and you do not have to fly to one of the two llustrated IAFs on the arc if you have the clearance.
Unless otherwise
vectored to a position from which the approach may be made without flying the arc, the way I understand it, you
must start the approach *AT* a published IAF—and for DME Arcs, that includes a specified "where" (radial) as well as a specified "how far" (DME).
(Consider being out in the mountains, IFR, but non-radar, and you get "Airline 1234, cleared for
an approach to the Blank airport—call us at such-and-such when you're on the ground." You're going to stay on an airway or other terminal route and fly a full procedure--not just veer off and go intercept an arc at other than a published fix.)
A RMI makes a DME arc as easy as shooting fish in a barrel; even without, they're not overly difficult.