PPRuNe Forums - A320 PTU Inhibited?

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A320 PTU Inhibited?

Hello, new user here and I'll try to keep it short: Why is the PTU inhibited during the first engine start?

I recently bought flightsimlabs A320 and love it! So now I am digging into the systems.

Thanks!

Reduced load on the engine driven pump maybe.

I guess, even when the cargo door is opening via the help of yellow elec pump, it's inhibited. (Provided both ENG's Off)

Quote:

Originally Posted by HOVIS (Post 11424362)

Reduced load on the engine driven pump maybe.

That makes sense. I guess you wouldn't want two sources of pressure feeding a system at one time.

Thanks for the reply!

Quote:

Originally Posted by JumpmanJr (Post 11424323)

First engine start everything that is rotating takes it's power from APU or external cart. If PTU is not inhibited the EDP will impose more load on the pneumatics provided by that source and may affect N2 rotation. After first engine start the EDP of that engine is will provide power to PTU so doesn't affect 2nd engine start.