Is the term "as soon as practical" for shutting down the engine explained somewhere in written form i.e. Bell 412 Training or Operation manual ? Do we have any authority to quote ?

The Pilot action when given that instruction depends purely upon the situation the Pilot finds himself confronting.

The more you need that engine's power to safely fly the aircraft....the longer you take to comply if at all until safely on the ground.

The Caution Light color is "Amber" or "Yellow".....not RED. That alone should suggest the urgency that should be given to the problem.

That supposes there are no secondary indications of a problem....oil pressure, oil temperature, Ng Nf (N1, n2), exhaust temp, noises, vibrations, etc.

In my mind....engines are to be used as needed to allow as safe a landing of the aircraft as possible.

Memory serves me the such Emergency Drills are for shutting down one of two operating engines.....thus if already OEI....I am not going to shutdown that last engine until I am safely on the ground at the first suitable landing area.

So reading the lines and a little in-between:
Bell 412 at high altitude has a Eng chip caution.
Pilot shuts down engine.
Power from one engine not enough to maintain altitude.
Aircraft crashes.
Someone's assigned to investigate who has little knowledge of piloting and the performance basics of twin engine helicopters.
I do admire your persistence with this Craven Spirit but I don't really think that you are qualified and experienced enough to be investigating a B412 crash. I hope this is not taken the wrong way but you appear to be out of your depth and lacking in the support you need to investigate.

Same here Craven Spirit.
I feel sympathy for the pilot of the aircraft (if he is still alive), if you are deciding his fate with your report.
You must be very desperate if you are asking Pprune for help in such an important event.
Please source the correct documents, go to a very experienced Bell 412 squadron or pilot and get them to educate you as to what perhaps happened.
:ugh:

In the meantime, I urge Ppruners NOT to offer any advice, for fear it may be used to destroy someone's career!
That even means you ChopJock!!!!

Mind if we remind you of this statement every now and then?