B737 Abort decision with engine overheat indication.
It is known that Boeing recommend that you do not abort the take off above 80 knots for master caution light indications. Some operators have their own rules setting that limit airspeed at 100 knots. Master caution - engine overheat annunciation as example.
Engine fire warnings in the simulator are usually preceded by an engine overheat indication. At least that is how some 737 simulators are programmed. I have no statistics readily at hand to advise what percentage of real engine fire warnings are preceded by an overheat indication - and in fact how many seconds can be expected between first overheat indication and a fire warning (if a fire is detected). This suggests there is a grey area in the decision making process to therefore abort on an overheat if the event is sufficiently below V1 to warrant an abort over 80 knots.
Example: One simulator is set up to give overheat indication approximately 4 seconds after the instructor presses the fire warning button. Keep in mind that the aim of the exercise is to have the crew initiate an abort at the fire bell providing the speed is an appropriate safe figure below V1. 15 knots, maybe which allows for shock, horror and then reject action.
Another simulator for same aircraft type may be programmed to actuate the fire bell the instant the instructor hits the engine fire warning button on his panel - that is, no prior overheat indication. That makes the abort decision more clear cut.
The problem arises when in the first example the instructor is forced to tell the pilot that he should play the game and pretend not see the master caution and overheat light come on and only abort at the sound of the fire bell and lit fire switch. This is a dodgy way of achieving the aim of the exercise.
Notwithstanding the "official" Boeing view, and in the light of a paucity of reliable gen on the subject, I tend to the view that an engine overheat indication during the take off run warrants strong consideration of an abort well beyond the 80 knot limit and probably up to 15-20 knots below V1. The purists and pedantic will have other views no doubt.
My reasoning? Worst case is strong possibility of fire warning following the overheat indication. After all, isn't that why the simulator is certified to cover that probability? Not a good thing to take a fire into the air when a competent pilot should execute an abort safely and sort out the fire on the ground.
Also an overheat indication is either a false warning or something is very wrong with the engine. It is unwise to gamble on a false warning. If something is very wrong with an engine then at 15 knots below V1 an abort is probably a safe bet.
No situation will be exactly the same but in the simulator an instructor has the responsibility of giving the best advice he can offer commensurate with his own experience on type.
Strict adherence to Boeing recommendations will earn the pilot kudos in the simulator, but it is these grey areas of "should I - or shouldn't I" abort with a overheat indication that concerns some instructors in their efforts to give the most reliable advice.
Comments appreciated.