2 Sheds,
If I have inadvertently refer to Our Beloved Bible in disparaging terms I should be struck off! I have no doubt that in certain circumstances as quoted by responders the passing of temp has a relevance. However, Dixi is referring to conditions where perf is highly likely to be limited by very high temps and the previous two examples are probably from a by-gone age. (Anyway, surely pistons at high temps also need the figure for perf reasons where air density might be an issue.) It is just that the turbine types that use our place have no interest in the air temp, as clearly their FMS does not require it and with electrical engine management these days fuel management relative to temp is auto. Even the Chief Pilot could not think up a reason why he would want to know! So I wondered you see... [How much of MATS1 is specified - or not - by PANS-ATM?!!]