Hydraulic system 3 and PTU

System 3 controls

Locate the system 3 electric-pump controls and the separate PTU selector on the overhead.

Check 3A

FSS says pump 3A is powered by AC ESS BUS and highlights that note in red, but the current Welcome page does not explain the highlighting. HYDR, ELEC and Service Update 1 do not independently confirm the feed. Treat it as unconfirmed and check the bus, pump and pressure indications in your installed aircraft.

Check 3B

FSS describes 3B AUTO operation in response to a 3A pump failure; ON overrides that logic.

Check the PTU selection

AUTO permits operation according to the system logic; OFF and ON have different effects. FSS also states that the PTU does not work on the ground.

Use the synoptic

Compare the control positions with actual pump, pressure and PTU indications.

HYDR checklist

Follow the applicable normal or abnormal procedure before changing a pump or PTU selector. ^[54]