This is one of those conundrums where you might very well be "damned if you do and damned if you don't" . The correct answer is determined retrospectively by the outcome on the day .... and the Judge at the Enquiry ... if the outcome was less than fortunate on the day ..
A well considered, thought provoking, reply, JT. Nicely put.
Interesting statements noted that structural failure due fire damage could occur with 3-4 minutes. Maybe so, although others may have contrary opinions on the safe time left.
Yet, in the many Pprune posts on engine fires (theory of) observed over several years, the majority of correspondents felt there was no great hurry to close down the engine and firing the bottles. These opinions appear to be based on the theory that the engine will probably fall off the wing before causing fatal structural damage. Again all theory and precious few facts.
In the simulator we see time and again, pilots who delay actioning the fire bottles until at least a minute - and worst case two minutes, after the initial fire warning. "There is no urgency" is their mantra - the excuse being the aircraft must be got under control before the crew look around the cockpit to see what the red lights are all about.
If an engine has failed after V1, (whether simultaneously with a fire warning or not) I would have thought the pilot would have not only immediately had the aircraft under control but the crew would have taken action to shut down the engine and fire a bottle if appropriate. This is notwithstanding the oft mentioned minimum height of 400 ft being attained before the first action is started.
Complacency in handling an engine fire can be potentially dangerous. There is no authorative guide that explains how much time is available before structural failure occurs following an un-actioned engine fire.
That being the case, a crew cannot afford to take the risk that all will be well and the bottles can be actioned at pilots leisure. The 3-4 minutes of safe flight available mentioned in these posts, suggests that others think along similar lines?