B737 NG PTU and LGTU

[ifleeplanes]

With a loss of hydraulic B the PTU uses system A to power the LE devices. Does this just use system A pressure or does it actualy use system A fluid?...(think its just pressure but not sure)

Equaly with loss of system A, System B powers the LGTU to enable normal gear retraction (with a few specific requirements). Does this just once again use the B pressure to raise the gear or does it actualy use B fluid?

[CaptainSandL]

PTU: Pump is pressurised by system A but the fluid is still from B. So if you were to lose all B quantity the PTU would not work.

LGTU: Uses system B pressure and fluid.

S & L

[ifleeplanes]

Thanks for that Capt S&L....was as I thought but wasnt 100%

[Buter]

For what it's worth, the LGTU doesn't care at all about hyd sys A, only eng 1 N2 (56% springs to mind, but certainly willing to be corrected)

Cheers

Buter

[CaptainSandL]

Correct, which is why you can despatch with the number 2 engine N2 gauge u/s but not the number 1.