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Boeing 737-800 NG · Live schematics

System schematics

Operate the switches and introduce failures — the diagram shows where fuel, power or pressure flows and what it means for the pilot.

Unverified — check your manualText on this page is written from general knowledge. Figures marked ✓ are checked against official FAA/EASA data.See verified data

ATA 29 Hydraulic Power · Systems A and B each have an engine-driven pump and an electric pump; the standby system backs up rudder, leading edge devices and thrust reversers.

Where it is

Location of Hydraulic System (A / B / Standby)
Hydraulic System (A / B / Standby)

What it looks like

Main gear and open wheel well (no main gear doors on the 737)
Main gear and open wheel well (no main gear doors on the 737) · illustrative image
ENG 1 pumpELEC 2 pump (A)ELEC 1 pump (B)ENG 2 pumpSYSTEM ASYSTEM BSTANDBYGear, NWS, altbrakes, controlsFlaps, normalbrakes, controlsRudder, LEdevices,reversers

Controls

Engine 1

Engine 2

ELEC 2 (A)

ELEC 1 (B)

FLT CONTROL STBY RUD

Inject failures

What this means

  • Both main systems pressurised.

How it works

  1. Systems A and B each have one engine-driven pump and one electric pump at 3,000 psi.
  2. System A: engine 1 pump plus electric pump 2. System B: engine 2 pump plus electric pump 1 — crossed for redundancy.
  3. The standby system has an electric pump and powers the rudder, leading edge devices and reversers.
  4. If A and B are both lost, the ailerons and elevators work by manual reversion (cables).

How the parts work together

  • A and B both power the flight controls, so either alone can fly the aircraft.
  • The PTU uses A to drive B's autoslats; LETS can retract the gear with B.
  • Standby activates automatically or by switch.

What each part does

Click a box in the diagram or a part below to highlight it.

EDUCATIONAL USE ONLY. Content is summarised from manufacturer documentation for learning. It is not approved flight or maintenance data. Always use the current, aircraft-specific POH/AFM, FCOM, QRH, AMM and operator procedures.