hydralic

1. 1
UNIVERSITI KUALA LUMPUR
MALAYSIAN INSTITUTE OF AVIATION TECHNOLOGY
HYDRAULIC AND PNEUMATIC SYSEMS
(AAB 20603)
REPORT ON CARRY OUT MAIN HYDRAULIC SYSTEM COMPONENT
IDENTIFICATION AND INSPECTION
PREPARED BY:
NAME ID NUMBER
AMIRUL ZARIF BIN ABDUL JALIL 53211219097
AHMAD SAIFI RABBAANI BIN MUHAMAD 53211219075
MUHAMMAD HASIF BIN IBRAHIM 53211219076
MOHAMMAD AIMAN NAIM BIN MOHD ROSLI 53211219087
MUHAMMAD IZZUDDIN BIN ZAILAN 53211219077
MOHAMAD KHAIRI AKRAM BIN AZAMAN 53211218145
CLASS 4 XBME 1
PREPARED FOR
SIR RASHIDI BIN RAHIM
SEMESTER JULY 2019

2. 2
TABLE OF CONTENT
CONTENTS PAGES
INTRODUCTION 3
OBJECTIVE 5
TOOLS AND EQUIPMENT 5
REQUIRED MATERIAL 5
PROCEDURE AND SAFETY 5
OBSERVATION AND ATTACHMENT 6
CONCLUSION AND REFERENCE 8

3. 3
INTRODUCTION
Hydraulic systems in aircraft provide a means for the operation of aircraft components. The
operation of landing gear, flaps, flight control surfaces, and brakes is largely accomplished with
hydraulic power systems. Hydraulic system complexity varies from small aircraft that require fluid
only for manual operation of the wheel brakes to large transport aircraft where the systems are
large and complex.
To achieve the necessary redundancy and reliability, the system may consist of several
subsystems. Each subsystem has a power generating device (pump) reservoir, accumulator, heat
exchanger, filtering system, etc. System operating pressure may vary from a couple hundred
pounds per square inch (psi) in small aircraft and rotorcraft to 5,000 psi in large transports.
Hydraulic systems have many advantages as power sources for operating various aircraft
units; they combine the advantages of light weight, ease of installation, simplification of
inspection, and minimum maintenance requirements. Hydraulic operations are also almost 100
percent efficient, with only negligible loss due to fluid friction.
Fluid storage
System fluid is stored in a spherical reservoir; fluid contents are indicated by an integral level
indicator tube. The top of the reservoir incorporate an inward relief valve through which a supply
of air at cabin pressure enters to provide a positive fluid head an adjacent outward relief valve
prevents a permanent cabin bleed and excessive pressure build up. A drain pipe with a plug is
fitted at the base of the reservoir. A gauze filter is provided in the filler neck
Power generation
Fluid is drawn from the reservoir. Through a suction filter, by 27-cylinder radial pumps driven one
by each engine. An on/off valve in each suction line is interconnected with the related engine HP
fuel cock: isolation of the hydraulic fluid supply is, therefore simultaneous with engine shut down.
A restrictor in a by pass round valve ensures that a limited supply of fluid reaches the pump for
lubrication purposes whilst the engine is wind milling with HP fuel cock off. System oressure is
controlled by a cut out valve assembly, which enables the pumps to be off loaded, when maximum

4. 4
system pressure is reached, by providing a idling circuit back to the reservoir. In the event of cut
out failure or system blockage, a full flow relief valve prevents build up of excessive pressure in
the delivery line by returning fluid to the reservoir at low pressure, thus preventing excessive heat
generation. A spring loaded thermal relief valve, downstream of the cut out valve, provides further
system protection.
On aircraft embodying Mod. 255764 self seling ground test connection are fitted in the reghthand
engine pod, allowing a ground test rig to be connected to operated the system.
On aircraft embodying mod 251847 a pressure filter is fitted between the cut out valve assembly
and the thermal relief valve.
Accumulators
2 cylindrical piston type accumulators , each fitted with a pressure indicator and air charging valve,
are incorporated in the system. 1 is the main accumulator, providing normal system backing: the
other acts as an emergency brake accumulator, and stores sufficient pressure for brake operation
in the event of complete system failure. Loss of normal braking system pressure is prevented by a
spring – plunger pressure maintaining valve.provided that main system pressure is normal. The
valve remains open; if pressure falls below preset value it closes to retain the accumulator pressure
for braking only.

5. 5
OBJECTIVE
1. To apply the knowledge on Main Hydraulic System component identification and
inspection with hands on practical.
2. To ensure familiarization of the construction of Main Hydraulic System component and its
parts.
3. To detect any defect on Main Hydraulic System component and its parts.
4. To rectify the defect detected on the Main Hydraulic System component and its parts.
TOOL AND EQUIPMENT
1. HS 125 Aircraft
2. Torchlight
3. Toolbox C/W Common Tools
4. Maintenance Step
REQUIRED MATERIAL
1. WD 40
2. Rags
PROCEDURE AND SAFETY
1. Make sure that the aircraft is choke and the park brake in on
2. Make sure all hydraulics supply is off
3. Wear proper safety attire during the practical

6. 6
OBSERVATION AND ATTACHMENT
For this practical we have identified 8 main component that need to be identified which is :
NO. COMPONENT ATTACHMENT
1. Reservoir
2. Pressure filter
3. Suction filter
4. Air brake jack

7. 7
5. Emergency brake reducing valve
6. Nose wheel steering jack
7. Flap control unit
8. Emergency brake accumulator

8. 8
CONCLUSION
These are 8 major component for hydraulics system in aircraft HS125.. Inspection need to be
carried out by following the instruction from the manufacturer’s manual. All the defects found
have to be rectified in accordance with the maintenance manual. In this practical, we found that
the component were in a good condition and the next rectification is scheduled.
REFERENCES
1. HS 125 Maintenance Manual Chapter 29-10-00
2. Task Card PWS 11.11A