Hydraulics Flashcards
In light aircraft and helicopters, brakes are operated using a (1) _________ hydraulic system, with pressure being provided by the force from the
(2) ________
(1) Passive, (2) Pedals
For transport aircraft, the reservoirs of a hydraulic system are typically pressurised by?
By air from the pneumatic system
Purpose of an accumulator in a hydraulic brake system is to?
Supply an emergency reserve of power in the event of a hydraulic failure
Why is it important to clean up any hydraulic fluid spilled on the aircraft fuselage?
Risk of corrosion.
The hydraulic device, which functionality is comparable to a diode in an electric circuit is a?
Check valve.
The purpose of pop out indicators being fitted to filters in hydraulic systems is to?
To warn of an impending by-pass situation.
When powering up a hydraulic system, the level in the reservoir will?
Decrease slightly
Large transport aeroplane hydraulic systems usually operate with a system pressure of approximately?
3000 psi
What is the function of a standpipe in a hydraulic system reservoir?
It supplies the main feed line.
The pressure in a hydraulic system is measured relative to?
Atmospheric Pressure
The purpose of a stand (stack) pipe on a supply line inside the reservoir of a typical hydraulic system is to?
Ensure hydraulic fluid supply for emergency hydraulic system operation
An aircraft hydraulic system that has low-pressure fluid flow in the system when the system actuating mechanisms are idle is referred to as?
An Open Centre Hydraulic System
In a hydraulic system, the reservoir is pressurised in order to…
prevent pump cavitation
What may happen if a mineral based hydraulic oil is used in a system designed for synthetic hydraulic oil?
Seal damage may occur
A demand pump works by supplying (1)_______ and (2)_______
Variable Volume
Hydraulic power is a function of?
System pressure and volume flow
The function of a hydraulic fuse is to?
Prevent total system loss in the event of a hydraulic leak.
How is filtration in a modern hydraulic system usually ensured?
By filters in both the pressure and return lines.
In a hydraulic system, overheat detectors are usually installed where?
at the pumps.
In transport aircraft, the pressure of hydraulic fluid can be indicated by?
A pressure transducer.
Parameters to monitor a hydraulic system in the cockpit are?
Pressure, fluid temperature and quantity
In an aircrafts hydraulic system, the Power Transfer Unit (PTU) is driven by?
Hydraulic driven pump.
Hydraulic systems, when operating normally, are pressurised by?
An engine pump
The viscosity of a hydraulic fluid should be?
Low to minimise power consumption and resistance to flow.
A hydraulic low pressure alert is the first indication of?
The pump output pressure being insufficient
Shuttle valves will automatically switch?
Hydraulically operated units to the most appropriate pressure supply.
Pascals Law States that if a fluid in confined space is pressurised by an external force, the fluid pressure will be sensed?
equally throughout the fluid.
A NRV valve can also be called?
A check valve.
A Power Transfer Unit (PTU) is powered by?
A hydraulic motor
What instrument readings would pilots observe if the aircraft was experiencing a gradual internal leak in the hydraulic system?
Low/irregular pressure, high temperature
The function of a hydraulic selector valve is to?
Direct system pressure to either side of the piston of an actuator.
What is the common operating pressure of the hydraulic system on most large transport aeroplanes?
3000 psi
Assuming an accumulator is pre-charged to 1000 psi and the hydraulic system is pressurised to 1500 psi, the accumulator gauge will read?
1500 psi.
What is the main purpose behind employing pressurised hydraulic reservoirs on jet transport aircraft?
To assure the pump inlet is provided with a continuous and adequate supply of fluid free from foaming.
