ATR 72 ITT Limit during Take Off

[bucks_raj]

The FCOM Limitations gives a graph on ITT limit @ TO which comes to about 765C . How ever the ITT warning only comes on at 800C . The 72 600 has been told by the mfg to continue take off if BOOST is being used and itt is 765<itt<800 .

How ever it doesnt seem very clear as to what the limit on a 500 should be..

[Poussin]

The temperatures and procedures for the 500 and 600 are the same. Boost On and Off.

With the BOOST Off, the limit for the ITT during take off with is 765 degrees (decreasing to lower values if the OAT is below 15 degrees C).

However with the BOOST on. (In case of high airport elevation or high temperature), you are allowed to continue the take-off up to 800 degrees.

Above 800 degrees you will have an engine temperature over limit in any case and will risk and engine fire.

Switching the boost On allows you to get a little bit more performance from the engine by raising the max ITT from 765 to 800. However the engine life time recorded will be increased at 1,4 the normal time, thus reducing the time between engine visits.

[Poussin]

My apologies, I made a mistake on my previous comment.
Boost ON or Boost OFF, the limit is ALWAYS 765 deg (if OAT> 15 deg)
The boost will raise that limit a little bit if the ITT limit is below 765 (for example in high airport elevation) but the max will always be 765.

[snipper0012]

Our airline just started using the 72-500 version of ATR. Earlier 42-500 was a big hit in the airline, apart from its Icing issues. What I am still confused abt is the Boost On and Boost Off charts for ATR 72. The FCOM says nothing abt Boost. I would be highgly grateful if anyone could please enlighten me abt Boost Function, or forward me any write up explaining it. Boost Function under the Powerplant section of FCOM 1 says N/A, but i would still want to know what is it abt.

Regards