I have a feeling that a couple of posters in this thread miss the point about information. A fire indication doesn't mean "evacuate immediately"
I think the point is: a fire indication does not neccesarily mean an engine fire. (in the sense of "usual engine fire within the engine fire zone for which the aircraft is designed")
A fire indication should not trigger anything automatic immediately. No standard engine fire procedure, no evacuation.
An engine fire warning should trigger a (very quick) investigation into the situation, followed by appropriate action. It is an anachronistic situation, that in many aircraft the passengers can see the fire situation clearly on their IFE (in colour and HD...), but neither the cockpit nor the cabin crew has a clue.
It would be interesting to see a statistic: How many engine fire indication do indeed indicate that there is a fire the aircraft and the fire warning/extinguishing system, the fire containment and the procedure is designed for? How many are false warnings? How many are a totally different situation (like a catastrophic engine failure, a fire originating outside the designated fire zone the extinguishing system can handle, a fire already spreading beyond the fire zone)?
No matter whether you finally will evacuate, it is always a good idea to prepare for an evacuation as early as possible, as typically time is a critical factor.
As we have seen in singapore, the decision to leave evyone on board and let the fire brigade do their job fast and without disturbancy may be the more clever action. Anyway you should as soon as possible
think through the different alternatives and
prepare as fast as possible. Whether you actually will evacuate may be decided later, but no time should be lost prior to that decision. You can not revover time lost. Turning the aircraft into a favourable position with respect to the wind or to improve access for the fire services will never hurt.
Firing both bottles following the SOP may save your a**** because nobody can accuse you of doing something wrong, Sometimes it is more important to save everybody on board.
You would have thought that we would have learned the lesson
"we" may have learned the lesson, but do we teach it to new pilots?