Power Distribution I
What is the purpose of a hydraulic system?
To enable movement of various components that is unachievable, or impractical, using human power alone.
Why do some aircraft use electrically operated selector valves?
It is sometimes convenient to locate a selector valve at a position remote from the crew compartment, and to eliminate the need for extensive mechanical linkage.
What does a sequence valve do?
Sequence valves control the sequence of operation between two branches in a circuit; they enableone unit to automatically set another unit into motion
What is the main purpose of the shuttle valve
To isolate the normal system from an alternate or emergency system
name 3 parameters are monitored in a transport category aircraft hydraulic system
Quantity, temperature, pressure,
What component is used to translate Pilot input into a mechanical output and to distribute the power to where it is needed?
A control valve
When the Electrically Operated Selector Valves is de-energised the valve is said to be in what position?
NEUTRAL or OFF position
What are the two different types of sequence valves?
Pressure and Mechanical operated
The Engine-Driven Pump Shut-Off Valve is used to ......?
stop flow of hydraulic fluid to the EDP in case of fire when the FIRE Handle is pulled
What does the hydraulic pump low-pressure warning system indicate?
when the pressure of any hydraulic pump on the aeroplane decreases to less than normal
What is the purposes of a selector valve?
To direct fluid to the appropriate side of an actuator and to provide a return path for fluid displaced from the opposite side of that actuator.
Why do aircraft Hydraulic systems use check valves?
to limit flow to one direction only
What does a priority valve do?
A priority valve gives higher priority to the critical hydraulic subsystems over non-critical systemswhen system pressure is low
Name 4 types of actuator?
Single acting, double acting un-balanced, double acting balanced, cushioned, lock, rotary
What does the hydraulic fluid overheat warning system indicate?
when the temperature of hydraulic system fluid or the hydraulic pump is higher than normal
How are selector valves operated?
These valves can be manually or electrically operated
What are the three types of check valve?
Ball Cone Swing (Flap)
Quick disconnect valves are used to .........?
prevent the loss of fluidwhen components are removed or at system servicing points
Name 4 different contours of seal
O-ring, U cup, U-ring, V-ring, Male and female version of V-ring
Name 6 aircraft systems the hydraulic system interfaces with
The Electrical Flight Control System, providing flight control computers with hydraulic status and failures for the activation or deactivation of the related flight control servo actuator
Slat and flap control computers
Landing gear extension and retraction control computers
Braking system control computers
Nose wheel steering computers
The Electronic Centralised Aircraft Monitor System (ECAM) or the Engine Indicating and CrewAlerting System (EICAS) for hydraulic system indication
The Centralised Fault Display System (CFDS) for a last-flight-leg report in case of certainhydraulic failures
Fuel tank quantity systems for hydraulic case drain fluid cooling before fluid goes back to the reservoir,
Fire protection, with engine fire handle/switch movement causing the hydraulic shut-off valveto close, isolating the engine-driven pump of hydraulic fluid in case of fire
The closed centre valve _______________ when it is in its neutral position
stops the flow of fluid
What does an orifice check valve do?
allows full flow in one direction and restricted flow in the reverse direction
What is a Hydraulic fuse
A safety device that detects a sudden increase in flow, such as a burst downstream,and shuts off the fluid flow
Why are back up rings used with o-rings
prevent extrusion of o-ring
Name 4 things you would find on a hydraulic system control panel
Brake source select switch, Hyd sys 4 EMDP switch, overheat warning lights, quantity gauges, qty test switch, low pressure warning, pump switches, air pump run indicator, low quantity indication, Sys pressure indication