I have 2 questions regarding the startup procedure. Before engine start, the manual says the starter switch should be cycled: left, off, right, off. Why is this needed? I read somewhere it's meant to bleed all remaining hydraulic pressure, should there be any, before testing the HI/LO emergency flight hydraulics. Is this true?
Also, after starting the right engine but before starting the left one, you're supposed to crank the left one, hydraulic transfer pump to normal, build about 2500 psi combined pressure, then starter off, hydr. shutoff. Why is this needed? Also, the pressure that builds up like this bleeds off rather quickly if I don't start the left engine right after it.
Thanks in advance!