b. Is it mandatory to follow company SOP ,always or sometimes or it depends?
Folks,
I don't know if there are any wrinkles to the contrary under Singapore Air Law, but I certainly know what the law is in Australia, based on not just the air law, but at least one full bench of a Court of Appeal decision, the power of the pilot in command overrides any other consideration in an emergency, including any provision of an AFM/FCOM etc. to the contrary.
The relevant ICAO Annex, and the laws of CA/NZ/US/EU say more or less the same thing, but I can't quote any particular superior court precedents outside of Australia to confirm the conventional interpretation of the powers of the PIC.
As for this accident, based on half a century of knowledge (including fires on the ground) and experience, this aircraft should have been evacuated as soon as it came to a stop.
Tootle pip!!
PS: The CASA draft CASR Part 91 muddies the waters, surprise! surprise!!