Good question. As the MTCA, in terms of obstacle clearance, is calculated more conservatively than the MEA, then it will be safe. The MCTA may on occasion actually be higher then the MEA (or MSA for the that matter!) because it is calculated differently.
With consideration for the initial approach altitude constraint and MSA, I don't see how descending down the MTCA would be problematic in the least on an RNAV GPS/GNSS/RNP arrival.
Last edited by Sciolistes; 24th October 2011 at 16:23.