Page 71 D633W101-BEJ Sep 05/2002
MAIN HYDRAULIC SYSTEMS -LEFT AND RIGHT SYSTEMS -FUNCTIONAL DESCRIPTION
The ACMP and EDP filter modules each have a pressure transducer to measure pump output pressure. A temperature transducer in the case drain line of each filter module measures pump case drain fluid temperature.
A system pressure transducer measures hydraulic system pressure.
See the hydraulic pressure indicating section for more information ().
Each ACMP has a temperature switch that is a part of the pump. The temperature switch closes to indicate a pump overheat condition.
BEJ ALL PRE SB 777-29-0024
The ACMP temperature switch is not used.
BEJ ALL POST SB 777-29-0024
The ACMP temperature switch is wired in parallel with the ACMP case drain temperature transducer. When the temperature switch closes, it simulates a high temperature signal by connecting a fixed resistance to the ACMP temperature transducer input on the HYDIM card.
BEJ ALL
See the hydraulic temperature indicating section for more information ().
Pressure Relief
A pressure relief valve on the EDP filter module protects the system against overpressurization.
EFFECTIVITY BEJ ALL 29-10-00
Page 72
D633W101-BEJ Sep 05/2003
MAIN HYDRAULIC SYSTEMS -LEFT AND RIGHT SYSTEMS -FUNCTIONAL DESCRIPTION
EFFECTIVITY BEJ ALL PRE SB 777-29-0024 29-10-00
Page 73
D633W101-BEJ May 05/2003
MAIN HYDRAULIC SYSTEMS -LEFT AND RIGHT SYSTEMS -FUNCTIONAL DESCRIPTION
EFFECTIVITY BEJ ALL POST SB 777-29-0024 29-10-00
Page 74
D633W101-BEJ Sep 05/2003
MAIN HYDRAULIC SYSTEMS -CENTER SYSTEM -FUNCTIONAL DESCRIPTION
General
The center hydraulic system supplies pressurized hydraulic fluid to operate these systems:
*
Nose landing gear actuation
*
Nose landing gear steering
*
Alternate brakes
*
Main landing gear actuation
*
Main landing gear steering
*
Trailing edge flaps
*
Leading edge slats
*
PFCS.
Fluid Supply
The center system reservoir contains the hydraulic fluid supply for the center system hydraulic pumps.
A reservoir pressurization module supplies pressurized air from the pneumatic system to pressurize the reservoir.
The reservoir supplies fluid to the ADPs, the RAT, and one of the ACMPs through a standpipe. The other ACMP gets fluid from the bottom of the reservoir.
The reservoir also supplies hydraulic fluid to the landing gear alternate extension system.
EFFECTIVITY
BEJ ALL
Pressurization
The ACMPs are the primary pumps in the center hydraulic system and are normally on.
The ADPs are the demand pumps in the center system. They normally operate only when the center system needs more hydraulic flow capacity.
The ram air turbine system supplies an emergency source of hydraulic power to the center hydraulic system flight controls.
Filtration
Filter modules clean the pressure and case drain output of the hydraulic pumps.
A return filter module cleans the return flow of hydraulic fluid from the user systems. The module can be bypassed.
The heat exchanger cools the hydraulic fluid from the ACMP case drains before the fluid goes back to the reservoir. ADP case drain fluid does not go through the heat exchangers.
Hydraulic System Sensors
A reservoir quantity transmitter and temperature transducer are on the reservoir. A hydraulic reservoir pressure switch is on the pneumatic line between the reservoir and the reservoir pressurization module.
29-10-00
Page 75 D633W101-BEJ Sep 05/2002
MAIN HYDRAULIC SYSTEMS -CENTER SYSTEM -FUNCTIONAL DESCRIPTION
The ACMP and ADP filter modules each have a pressure transducer to measure pump output pressure. A temperature transducer in each filter module measures pump case drain temperature.
A system pressure transducer measures hydraulic system pressure.
See the hydraulic pressure indicating section for more information ().
Each ACMP has a temperature switch that is a part of the pump. The temperature switch closes to indicate a pump overheat condition.
BEJ ALL PRE SB 777-29-0024
The ACMP temperature switch is not used.
BEJ ALL POST SB 777-29-0024
