ATR42-300 operational procedure - engine cool time

[manene]

A note in the "after landing" checklist (normal procedures) of the ATR42-300 states: keep engine running at least one minute at ground idle power (condition lever between MAX and MIN RPM) before shutdown to assist in reducing residual heat build up in the engine and nacelle. Can someone please help to explain the technical significance and impact on the economic life of the engine of keeping the condition lever at the minimum or maximum RPM stops or midway between the two stops i.e. in which exact position would you derive maximum economic benefit for the life of the engine. Thank you.

[Waveman]

Once the power levers have been brought to ground idle it doesn't matter where the condition levers are between min & max - the ECU schedules enough fuel to keep the props turning at approx 71% (to give you AC Wild power). Normally the condition levers will still be at max from your landing. Of course you can feather one prop while taxiing in, but don't shutdown until the elapsed time has passed - lets the oil/engine temperature even out.

PS Any spare jobs for ATR drivers in Cape Verde?

[Mago]

The colder the engine is when you suht down it the colder it will be when you start it again, this in return means that you need less time with the starter ON before you get a "cold" temperature to start it without a hot start, remember that the 200 Cº limit is not so good in practice.
Also shuting down colder means that you will get to your times/cycles limits parts in better condition and thus cheaper shop visits.