Can the Landing gear be lowered when system A hydraulic pressure is lost in Boeing 737? In the FCOM OF BOEING 737 HYDRAULIC SECTION I went through the part Landing gear transfer unit that it is used to raise the landing gear at a normal rate when system A EDP volume is lost.
My query is if only the hydraulic system A is lost with landing gear up position can it lowered using system B hydraulic or do we need to use manual gravity gear extension?
Normal gear extension is by the A system; alternate gear extension is by manually releasing the up-locks, allowing the gear to free-fall into place. There is no provision for any other alternate gear extension beyond that, such as via the B or Standby hydraulic systems, electrics, pneumatics, or otherwise.