Hydraulic pressure, quantity and temperature
Select HYDR
Open the hydraulic synoptic before and after a normal system change.
Read pressure
Read each system’s digital pressure and its scale or pointer. Compare the result with the associated engine and electric-pump state; a pump selection alone does not prove normal pressure.
Read quantity
FSS describes the quantity indication as the percentage of fluid remaining in each hydraulic system. Compare the systems; do not confuse quantity with pressure.
Read temperature
FSS describes the displayed fluid temperature as measured in the reservoir. Consider it with the phase of flight and any system message.
Understand the PTU
The power-transfer unit transfers hydraulic power; it does not transfer fluid between reservoirs. FSS describes AUTO as allowing automatic operation and says the PTU does not operate on the ground. Check the selector and the HYDR indication.
Compare pump AUTO logic
For pumps 1 and 2 in AUTO, compare the indication with the flight or ground conditions. FSS lists engine or engine-driven pump failure, or flaps beyond zero, in flight. On the ground it requires flaps beyond zero plus takeoff thrust or groundspeed above 50 kt. Pump 2 has an additional single-engine taxi condition: engine 1 running and parking brake released.
Real aircraft and operator manuals are valuable background, but a particular electric-pump trigger must be checked against the simulated version and configuration.
On HYDR, FSS uses green for normal quantity and cyan when a reservoir requires refilling. A green flow line indicates pressure; white indicates no pressure, and a white/amber dashed line means pressure is undetermined. The distribution boxes identify the aircraft systems supplied by each hydraulic system and use the same green, white and dashed colour convention for pressure. For the pressure indication, FSS marks an amber digital value, scale or pointer as the cautionary operating range; this page gives no numeric pressure thresholds. Reservoir temperature is green in the normal range, amber in the caution range and red when the limit is exceeded. Check the pressure values and messages as well as colour. FSS HYDR synoptic [111].
The HYDR page uses a circle with a windmill for an engine-driven pump, electric pump or PTU; electric-pump icons are smaller than the engine-driven pump and PTU icons. The engine-pump shutoff valve is shown as a circle with an internal line. FSS specifically describes its in-transit state as a white circle with a white line diagonal to the flow line. The page does not provide a colour key for the steady valve positions, so use the overhead control to identify the command and the synoptic to read the reported state. FSS HYDR synoptic [111].
The overhead ENG PUMP SHUTOFF buttons control the engine-driven pump shutoff valves. FSS describes PUSH OUT as the normal position; pushing a button in closes the respective valve and isolates that engine-driven pump from its hydraulic system. Follow the applicable procedure before changing it.
The FSS HYDRAULIC page [54] says pump 3A is powered by AC ESS BUS and highlights that sentence in red. the current Welcome page [83] does not explain what the red highlighting means. HYDR, ELEC and Service Update 1 do not independently confirm the feed. Treat the note as unconfirmed; check the bus, pump and pressure indications in your aircraft. SYSTEMS/HYDR [111] · SYSTEMS/ELEC [93] · Service Update 1 [2]. [111] [54]