It depends on Malaysia / Air Asia's Etops rules. If for instance their Etops rules are the same as in Oz ( and there is no reason to assume they are) then unless there is an overriding compelling reason for the Captain to ignore the rules, then the Captain is obliged to land at Learmonth assuming that it is categorised as an Alternate or Adequate airport or the equivalents under Malyasian rules.
If the flight is not being conducted under Etops rules ( and assuming Malaysian rules are the same as Oz) then all the Captain is required to do is to have a good reason why he has flown past a suitable airport to a more distant suitable airport ( having a better chance at having the engine fixed or passenger comfort might not qualify).
If he didn't shut the engine down ( and there is no reason to assume he didn't ,) then he is not in an engine out situation and therefore has no special rules that are applicable.
Last edited by JamieMaree; 25th Jun 2017 at 11:27.