Re: DC-9 Flight Control/ hydraulic systems

From:         "David G. Davidson" <gerhard@onramp.net>
Organization: http://members.aol.com/tristar500/l1011
Date:         10 Jun 96 12:22:25 
References:   1 2 3 4 5 6
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Karl Swartz wrote:

> My impression had been that no more than 3 of the 4 are present in any
> one portion of the aircraft.  For example, one system in the L-1011 is
> located only in the aft section and does not venture forward to the
> wings, while another is present only in and ahead of the wings, never
> venturing back to the tail.

The A system has a 'fuse' that is designed to stop flow of A system
fluid (pressure and return) in case of a line rupture in the tail. This
fuse is located forward of the nbr 2 engine firewall and above the
stabilizer.

The fuse is an electrically operated valve that closes when differential
pressure between the pressure and return lines exceeds 35 psi. The valve
can only closes in flight.

All four systems power the stabilizer, but as you can see from the list
that is the only thing in the tail that D system powers.

A, B and C system all power the rudder and stabilizer.

---------------------------------------
L-1011 Hydraulic System

A System

Engine Driven Pump on number 1 engine (A1)

Power Transfer Pump driven by 'B' system (BA)

The following are powered by the 'A' hydraulic system

       Stabilizer
       Rudder
       Aileron, INBD, Left
       Aileron, OTBD, Left
       Spoiler 2L
       Direct Lift Control
       Autopilot Servos
       Leading Edge Slats
       Trailing Edge Flaps
       Tail Skid (tail skid not installed on -500 airplanes)



B System

Engine Driven Pump on number 2 engine (B1)

Power Transfer Pump powers 'A' system

Air Turbine Motor pump powered by pneumatic system (B2)

Electric Motor Driven Pump (B3)

Ram Air Turbine Pump (B4)

The following are powered by the 'B' hydraulic system

       Stabilizer
       Rudder
       Aileron, INBD, Left
       Aileron, INBD, Right
       Aileron, OTBD, Left
       Aileron, OTBD, Right
       Spoilers 1L, 1R, 4L, 4R, 6L, 6R
       Direct Lift Control
       Autopilot Servos
       Normal Brakes
       Parking Brakes



C System

Engine Driven Pump on number 2 engine (C1)

Air Turbine Motor pump powered by pneumatic system (C2)

Electric Motor Driven Pump (C3)

Power Transfer Pump powers 'D' system

The following are powered by the 'C' hydraulic system

       Stabilizer
       Rudder
       Aileron, INBD, Left
       Aileron, INBD, Right
       Spoilers 3L, 3R, 5L, 5R
       Leading Edge Slats
       Trailing Edge Flaps
       Landing Gear
       Nose Gear Steering
       Alternate Brakes



D System

Engine Driven Pump on number 3 engine (D1)

Power Transfer Pump driven by 'C' system (CD)

The following are powered by the 'D' hydraulic system

       Stabilizer
       Aileron, INBD, Right
       Aileron, OTBD, Right
       Spoiler 2R