Hydraulic pumps and indications

The HYDRAULIC overhead controls show what you select. The HYDR page shows the reported system state. Check both before interpreting a pump indication.

Hydraulic selectors

Identify the SYS 1, SYS 2 and SYS 3 pump selectors on the HYDRAULIC overhead panel. Record their current positions. Then open HYDR to read pressure, quantity and temperature.

AUTO or ON

For electric pumps 1 and 2, FSS describes OFF, AUTO and ON. ON commands continuous operation. System 3 has separate 3A and 3B controls; 3A has no AUTO position.

Consider the phase

In flight, FSS describes AUTO operation after the associated engine or engine-driven pump fails, or when flaps are selected above zero. Ground triggers are different; see below.

Consider taxi

FSS specifically notes a pump-2 AUTO trigger involving engine 1 and the parking brake in a single-engine taxi context. This is a system description, not a complete taxi procedure.

Observe the result

Check pressure and pump indications on HYDR. Do not infer pressure solely from a selector position.

Pressure mismatch

If the observed state differs from the documentation, record both engine states, flap position, ground/air state, parking brake and exact aircraft version.

On the ground, FSS describes the general AUTO trigger as flaps above zero together with takeoff thrust or groundspeed above 50 kt. It separately describes electric pump 2 starting in AUTO with engine 1 running and the parking brake released. Check both pump indications during single-engine taxi. Hydraulic pump discussion ^[197]. ^[54]