Apprentice wrote:Hello: As Caltech used to be carefully in his posts, I pay a check to Airbus A330’s “ Flight Deck and System briefing for pilots”, page 4.2. ““http://www.smartcockpit.com/docs/A330_Flight_Deck_and_Systems_Briefing_For_Pilots.pdf“ and, Airbus included and schematic with.. a PTU !!!. As A330 does not need PTU, I may suppose that Airbus included it to get $. And gave a false reason, “ in case of full hydraulic power lost, RAT will power Grren System , And PTU , using Green power, may pressurize Yellow System . Still difficult times but with less heavy FC.”
I still get the feeling that was an error in the PDF, or perhaps an option that was never taken up.
Apprentice wrote:Hi, Sorry again, reading same “FDASBFP” in “Abnormal Proccedures”, Airbus also consider this one:
“- in the event of engine 2 failure, the Yellow electrical pump runs automatically when flaps are not retracted”, thus pressurizing Yellow and Green System, using PTU. (See schematic no same page 4.2) .
Sorry Airbus, it looks that, beside Mx, there are cases when pump is needed....
In that particular case, there's no need for the PTU to pressurise the yellow system because it would be done with the electric pump.
My point is that the PTU adds a bit of redundancy but is not really necessary.