Mesaba03

Hello all, just reading and was wondering what ITT measures on the Saab 340. Also what does it mean to have takeoff power with APR or go around power? Sorry if it is not to clear, I just wanted to see if anyone knew. Thanks.

Bloodhound

In general, ITT measures the temp. at the high pressure turbine. I never flew the Saab so I'm not sure what APR is.

FlyerJosh

APR is "automatic performance reserve". It's an aircraft controlled "safety" that kicks in a bit of extra power automatically on the operative engine in the event of an engine failure on takeoff, usually for a few minutes. How much, how long, and what conditions kick it in depends on the aircraft.

ITT stands for interturbine temperature. On some aircraft it might be a temp reading at one location in the core, on others it might be an average of temperatures throughout the engine (as measured by different sensors).

Mesaba03

Does APR kick in automatic, or can you overide it if you need extra power on takeoff?

FlyerJosh

It's automatic and not intended for use during normal operations.

Mesaba03

ok thanks for the help, I was just looking at my limitations and they give ITT numbers using takeoff, and takeoff with APR or go around power

FlyerJosh

Sure. Remember that I don't know about how the system works in the Saab, so Id suggest asking somebody in ground school exactly how the system works and applies to the limitations.

Mesaba03

This is also off topic from the thread, but we start doing TLR performance figuring this week. Are those hard to calculate? Just curious what to expect. Thanks everyone for your responses.

Fluboy340

APR: Automatic Power Reseve. Adds 7% more power to the operating engine during a engine failure. Is only armed for T/O/

Mesaba03

Thanks Fluboy!