40 Questions
What is the primary purpose of an avionics equipment rack in an aircraft?
To provide rigid mounting to withstand G-forces and vibration
Why is it important to touch the equipment metal case before disconnecting cables?
To prevent electrostatic discharge
What is the purpose of the key pins on the connector block of an avionics rack?
To ensure the correct LRU is connected in the correct place
What should be done immediately after disconnecting a plug from an electronic equipment?
Fit a conductive cover or cap to the disconnected plug
Why is it important to ground the aircraft before removing ESD sensitive equipment?
To prevent electrostatic discharge
What is the purpose of the screw latch at the front of an avionics equipment rack?
To secure the LRU in place
Why should personnel not touch the pins of any electronic component?
To prevent electrostatic discharge
What is the purpose of the alignment holes at the back of an LRU?
To align the LRU with the tapered pins on the rack
What is the primary goal of preventative maintenance activities?
To keep systems from breaking
What is the basis for judging the efficiency and effectiveness of a maintenance organization?
Ability to find and fix problems efficiently
What is the primary difference between Automated Test Equipment (ATE) and Built-In Test Equipment (BITE)?
ATE requires the LRU to be removed from the aircraft, while BITE is included in the component design
What is the primary purpose of upgrade or overhaul existing systems or components?
To take advantage of technological advances
What is the primary characteristic of Automated Test Equipment (ATE)?
It can be programmed to perform a series of tests without requiring human intervention
What is the primary goal of maintenance groups in the competitive air carrier business environment?
To keep aircraft safely in the air
What is the primary function of Built-In Test Equipment (BITE)?
To provide automated test capabilities within the component design
What is the primary reason for performing routine preventative maintenance activities?
To prevent failures from occurring
What is the primary purpose of a simple BITE system?
To perform a 'go/no-go' self-test on a specific module
What is the primary function of a flow chart in maintenance?
To direct the maintenance technician along a logical testing and diagnosis path
What is the primary reason for the high cost of No Fault Found (NFF) instances in avionics?
The cost of testing and logistics
What is the primary characteristic of a decision tree?
A series of 'if-then' statements
What term is used to describe avionics components that are repeatedly sent to workshops for the same reason but perform perfectly on the test bench?
Rogue units
What is the main cause of the majority of No Fault Found (NFF) instances in avionics?
Poor troubleshooting techniques
What is the main issue with avionics components?
They break down unexpectedly
What is the purpose of a Consistent Fault Set (CFS) in troubleshooting?
To list all possible failures that can explain a given set of symptoms
What is the primary cost in maintenance?
Unexpected maintenance
What is the term for a maintenance problem that seems to afflict avionics components disproportionately?
No Fault Found (NFF) unit
What is a heuristic in the context of troubleshooting?
A rule-of-thumb for problem-solving
What is the primary benefit of using heuristics in troubleshooting?
Increasing the speed of troubleshooting
What is the primary difference between a simple BITE system and a more sophisticated BITE system?
The level of complexity and sophistication
What is the primary purpose of recording performance information over a number of flight legs?
To identify patterns and trends in system performance
What is the primary consequence of No Fault Found (NFF) instances in avionics?
Increased costs due to labour and logistics
What is the primary goal of troubleshooting in avionics maintenance?
To identify the root cause of a problem
What is the importance of system knowledge in troubleshooting?
It is crucial to troubleshoot effectively
What is a common mistake made in troubleshooting?
Measuring the signal at the easiest point
What is the purpose of tracing the entire path of the signal?
To understand the system and ensure effective troubleshooting
What happens if the signal is correct at the halfway point?
You move closer to the end of the signal path
What is the benefit of using the Half Split method?
It is a time-proven method across multiple fields
What is the importance of avoiding inaccurate models of the system?
It ensures effective troubleshooting
What is the ideal location for the halfway point in the signal path?
At a point where the signal can be easily measured and splits the path in half
What happens if the signal is incorrect at the halfway point?
You move closer to the source of the signal
Study Notes
Electronic Component Handling
- Avoid touching pins of electronic components to prevent electrostatic discharge (ESD)
- Avoid touching sockets or pins within plugs of electronic equipment to prevent ESD
- When removing ESD sensitive equipment from aircraft, ensure the aircraft is grounded and power is removed
- Equalize electrostatic potentials by touching the equipment metal case before disconnecting cables
- Fit conductive covers/caps to disconnected plugs immediately
- When installing electronic equipment in aircraft, touch the plug outer shell to the outer shell of the equipment mating connector to equalize electrostatic potential
Avionics Component Installation
- Avionics equipment racks provide rigid mounting, cooling, and electrical connections to the aircraft
- Mounting restraint is achieved through tapered pins on the rack and alignment holes at the back of the LRU, with a screw latch at the front
- The connector block on the back of the rack has key pins to ensure correct LRU connection
Maintenance Tasks
- Maintenance tasks include routine preventative maintenance activities, such as inspecting, adjusting, lubricating, and replacing components
- Preventative maintenance aims to prevent components from breaking
- Maintenance tasks may also involve upgrading or overhauling existing systems or components to maintain regulatory compliance or take advantage of technological advances
Built-In Test Equipment (BITE)
- BITE is an automated test capability included in the design of a component, module, or subsystem
- BITE can range from simple "go/no-go" self-tests to sophisticated systems that record performance information over multiple flight legs and provide specific repair instructions
Troubleshooting Flow Chart
- A troubleshooting flow chart is a graphical representation of a logical testing and diagnosis path for a specific system
- The flow chart directs the maintenance technician to perform tests and observations, with each step branching to another test or conclusion based on the results
No Fault Found (NFF)
- NFF refers to a situation where an avionics component is removed due to faulty performance, but tests as perfectly good when returned to the workshop
- NFFs can cause unnecessary delays, labor costs, and logistical expenses
- Poor troubleshooting techniques are a common cause of NFFs
Troubleshooting Terminology
- Heuristic: a rule-of-thumb used for problem-solving, such as testing the most unreliable component first
- Consistent Fault Set (CFS): a group of all possible failures that can reasonably explain a given set of trouble symptoms
- Half-split algorithm: a troubleshooting technique that involves tracing the signal path, finding a halfway point, measuring the signal, and moving closer to the source or end of the signal path based on the results
Best practices to prevent Electrostatic Discharge (ESD) damage when handling electronic components and equipment. Learn how to safely remove and reconnect cables, and protect ESD-sensitive devices.
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