ETOPs/EDTO training around the world is based on ICAO annex 6 part II and compliance guidelines by EASA AMC 20-6 and (the far clearer)FAA AC120-42B.
The confusion around diversion airport selection is largely caused by the ICAO and EASA EDTO documents. This document is misleading when interpreted without context. They appear to suggest En-route alternates to be used are pre-determined by the dispatcher and that flight crews are expected to use the ones on the filed flight plan in the event of an engine failure. The glaring point easily missed is that it is written purely in the context of providing a legal minimum standard for dispatching a flight.
In practice dispatchers tend to reduce the number of nominated ERAs to the minimum required in order to reduce flight plan clutter. Often the NOTAM and weather package do not include non-nominated ERAs.
Many asian airlines training departments actually train their pilots based on this misconception. Compounding this is an institutional deferral to their 'OC' for diversion decisions.
In this case the crew may not have had the information at hand to properly evaluate Learmonth, especially under the physiological circumstances. It may well have been safer from a human factors perspective to follow the simpler option of returning to Perth.
Last edited by HPSOV L; 1st Jul 2017 at 16:54.