First I must declare that I am not a pilot and have no intention of telling pilots how to drive an aircraft so please consider my post with that in mind.
This incident seems to have generated a plethora of views and opinions and that immediately raised a query in my mind. What seems to have caused so much discussion is the question of landing "ASAP". From a QA point of view the use of "ASAP" in a procedure, if indeed it was used, has created an ambiguity that could have disastrous consequences.
If the aircraft constructor and the certifying authority mean "land immediately" that is what the procedures should say. If that it what they mean by "ASAP", they have unintentionally created a situation where the pilot in command may make decisions based incomplete information provided by observable indications and symptoms.
Whilst procedures cannot address every specific event, the constructor has to make his manuals address situations based on his risk assessments of the danger arising from a failure to structure, equipment and services in any particular area.
Let me pose an example. An uncontained engine failure in a heavy twin. The uncontained element being outboard of the engine causing severe damage to the underside and internal structure of the wing. No fuel, hydraulic or electrical failures evident to the pilot or crew. There would be no indication to the pilot that the wing might be in danger of imminent failure. So, in this situation, "land immediately" would be more apt than "ASAP", and that is what the manual should state.
Certainly, the pilot has to make decisions based upon the procedures provided and the situation in which he finds himself, that is his responsibility and is almost infinitely variable, but he does need clear and concise guidance for predictable situations.
Just to round things off, in the UK ambiguities in airworthiness manuals are subject to Mandatory Occurrence Reporting procedures in accordance with CAP 382 as mandated by the Air Navigation Order. As pilots, you folk are in the best position to identify such ambiguities, but a cautionary note, pilots are not necessarily the best people to resolve them.
Finally, I congratulate the subject pilot on a safe conclusion to his incident.