Scenario: You're flying along at altitude, lose comms, and maintain the highest of the altitudes and fly the appropriate course. You arive at your IAF, and there is no hold as part of the approach. What is the appropriate method of descending?

 

Well, assuming that you are at or later than your flight planned ETA, I would say just descend on the IAP once you have course guidance. If you aren't at your ETA to the IAF yet, hold on the airway that you approached the fix at until you're at your ETA, then continue onward.

 

MEA's may not allow a seamless altitude transition from enroute to an approach segment...you might be too high to get down. In that case you may hold at the IAF on the inbound radial, right turns while you descend to an altitude that allows you to proceed with the approach (unless otherwise published).

 

From our trusty AIM

6-4-1. Two-way Radio Communications Failure

........(c) Leave clearance limit.
(1) When the clearance limit is a fix from which an approach begins, commence descent or descent and approach as close as possible to the expect further clearance time if one has been received, or if one has not been received, as close as possible to the Estimated Time of Arrival (ETA) as calculated from the filed or amended (with ATC) Estimated Time En Route (ETE).
(2) If the clearance limit is not a fix from which an approach begins, leave the clearance limit at the expect further clearance time if one has been received, or if none has been received, upon arrival over the clearance limit, and proceed to a fix from which an approach begins and commence descent or descent and approach as close as possible to the estimated time of arrival as calculated from the filed or amended (with ATC) estimated time en route.