30 Questions
Where is the return line filter typically located in a hydraulic system?
At the midpoint of the return line
What is the primary goal of a preventive maintenance program for a hydraulic system?
To eliminate most hydraulic component failures
What is the primary function of the hydraulic fluid in an aircraft hydraulic system?
To transmit energy in the system
What is a common pitfall in many organizations' preventive maintenance procedures?
Not requiring maintenance personnel to follow the procedures
What is the minimum auto-ignition temperature of most aviation hydraulic fluids?
475 degrees C
What is the first step in developing a preventive maintenance program for a hydraulic system?
Identify the system operating condition
What is a critical property of hydraulic fluids used in aircraft hydraulic systems?
High flash point
What is the primary characteristic of a preventive maintenance program?
It is performance-oriented
Why are phosphate esters used as hydraulic fluids in aircraft systems?
Because they are very difficult to ignite at room temperature
What is the primary benefit of a well-implemented preventive maintenance program for a hydraulic system?
Elimination of most hydraulic component failures
What is a challenge in designing aircraft hydraulic systems?
Operating efficiently over a broad temperature spectrum
What is the primary role of hydraulic systems in various applications?
To transfer high forces rapidly and accurately over a long distance
What is the basic principle of hydraulics as stated by Pascal's Law?
Pressure applied to any part of a confined fluid transmits to every other part with no loss
What is the recommended approach to developing a preventive maintenance program for a hydraulic system?
Develop a program based on the system's operating condition
What is the formula to calculate hydraulic pressure?
Pressure = Force / Area
What is the characteristic of hydraulic pressure in a confined fluid?
It acts with equal force on all equal areas of the confining walls and perpendicular to the walls
What is the purpose of including environmental concerns in a Preventive Maintenance procedure?
To identify potential hazards to the environment
What is the application of more powerful and accurate hydraulic systems?
In maneuvering huge ships
What is the primary focus of the 5th step in creating a Preventive Maintenance program for a hydraulic system?
Analyzing the equipment's history to verify maintenance procedures
What is the purpose of including a list of safety precautions in a Preventive Maintenance procedure?
To minimize the risk of accidents and injuries during maintenance
What is the primary benefit of having a comprehensive Preventive Maintenance program for a hydraulic system?
Ensuring the reliability and longevity of the hydraulic system
What is the purpose of specifying the store room number for parts and materials in a Preventive Maintenance procedure?
To facilitate the identification and retrieval of necessary parts and materials
What is the primary goal of a Preventive Maintenance program for a hydraulic system?
To prevent unexpected failures and reduce downtime
What is the advantage of hydraulic systems in terms of pipe size and weight?
They can transfer high forces rapidly and accurately even in small pipes of light weight
What is the common approach to hydraulic system maintenance in most companies?
Allowing the hydraulic system to control maintenance at a higher cost
What is the recommended percentage of hydraulic troubleshooters in a maintenance workforce?
10% or less
What is the primary role of general hydraulic maintenance personnel?
Conducting preventive maintenance procedures
What is the primary goal of a preventative maintenance approach to hydraulic systems?
Developing a proactive maintenance strategy
What is the importance of having 'hydraulic knowledge' in maintenance?
It is power in hydraulic maintenance
What is the expected outcome of implementing a preventative maintenance approach to hydraulic systems?
Reduced maintenance costs and increased system performance
Study Notes
Hydraulic System Components
- A return line filter is located at the input side of the hydraulic pump and cleans out any contamination in the hydraulic fluid at the end of the return line.
Hydraulic Fluid Properties
- Hydraulic fluid should have a high flash point to prevent ignition in case of a leak.
- Special hydraulic fluids with fire-resistant properties have been developed for aviation use, such as phosphate esters.
- These fluids are difficult to ignite at room temperature but can sustain combustion if heated to temperatures above 180°C.
- The auto-ignition temperature of most aviation hydraulic fluids is in the range of 475°C.
- Hydraulic fluid should have adequate viscosity to work efficiently over a broad temperature spectrum.
Preventive Maintenance
- Preventive maintenance is essential to eliminate most hydraulic component failures.
- A preventive maintenance program should be developed and followed to obtain results.
- Steps to develop a preventive maintenance program include:
- Identifying the system operating condition.
- Determining the equipment manufacturer's requirements for preventive maintenance.
- Identifying the component manufacturer's requirements for hydraulic fluid and filters.
- Reviewing equipment history to verify the above procedures.
Preventive Maintenance Procedures
- Procedures must be written for each PM task and must be accurate and understandable by all maintenance personnel.
- The PM job plan should include:
- Tools or special equipment required.
- Parts or material required with store room number.
- Safety precautions and environmental concerns.
- A list of preventive maintenance tasks for a hydraulic system could include:
Hydraulic System Principles
- Pascal's Law states that "Pressure applied to any part of a confined fluid transmits to every other part with no loss."
- Pressure acts with equal force on all equal areas of the confining walls and perpendicular to the walls.
- Hydraulic pressure can be defined as the force exerted by a fluid on unit area, anywhere on the surface within the container.
Hydraulic Knowledge
- Hydraulic knowledge is essential for effective maintenance.
- It is recommended to divide hydraulic skill into two groups:
- Hydraulic troubleshooters (10% or less of maintenance workforce) who are experts in maintenance.
- General hydraulic maintenance personnel (90% or more) who provide preventive maintenance expertise.
Test your knowledge of hydraulic systems used in aircraft maintenance, including their application in steering and maneuvering devices. Learn how Pascal's Law is applied in these systems to transfer high forces rapidly and accurately.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
