Originally Posted by
plhought
What power setting/phase of flight were you at? On the PW12* series the bleed source will swap between P2.5 & P3 and you'll sometimes see ITT decreases as the increased bleed demand at certain torque settings may trigger a swap to P2.5 which is actually less demanding a source than P3. It's a system run by pressure switches and relays so it's not fancy.
Its during cruise and Max cruise power.
Thank you for the that, it kinda makes sense. 2.5 flows more than 3 ? I agree with you on the the pressure switches and check valves.