PW150A ITT measurement and ITT margin.

[Crossunder]

- Where is the Indicated Turbine Temperature measured on the PW150A?

- What is the minimum ITT margin before the engine needs a shop visit? (Or is ITT margin not considered at all?)

[barit1]

This is only a generic answer, not specific to any given engine.

ITT is the abbreviation for Inter-Turbine Temperature. It is measured between two turbine rotors. Typically it is used to determine the gas energy available to drive the low-pressure or power turbine.

In a three-rotor engine ITT could possibly be between the core and intermediate turbines, and I suspect this is the source of your PW150A question.

[noughtsnones]

Crossunder,
You may find the AIRCRAFT SERIOUS INCIDENT INVESTIGATION REPORT - Bombardier DHC-8-402 registration JA848C (http://www.mlit.go.jp/jtsb/eng-air_report/JA848C.pdf) helpful...

"ITT: Inter-Turbine Temperature or Indicated Turbine Temperature" (page 4 (pdf reader))

Paragraph 2.1.1 - footnote *1 "Turbine temperature refers to the combustion gas temperature near the inter-turbine and is calculated based on the temperatures sensed by the multiple sensors installed on the exhaust duct." (page 9 (pdf reader) page 2 of report)

Figure 12 illustrates 8 items in the exhaust duct, that I think are the associated thermocouples (page 47 (pdf reader) page 40 of report)

If you have local (or PWC portal) access to the Aircraft FIM, the report indicates, page 23 (pdf reader) page 16 of report, "TASK 71-00-00-810-814 Engine #1 (#2), Sudden Increase/abnormal ITT-Fault Isolation" and "Is the indicated turbine temperature (ITT) system correct (Refer to AMM TASK 77-21-01-720-801)?"

[Crossunder]

Thanks all! :ok: