ESD Failure Types

Questions and Answers

What is the primary characteristic of direct catastrophic failures?

The component will continue to operate but with reduced performance

The component is permanently damaged and will never function again (correct)

The component will only fail intermittently

The component will eventually fail due to ordinary operational stress

What is the main issue with latent failures due to ESD?

They are difficult to detect during testing

They result in high repair costs due to aircraft downtime (correct)

They cause immediate system failure

They are always detected at the avionics test bench

What type of failure occurs when an ESD event causes a current flow that is not significant enough to cause total failure?

Direct catastrophic failure

Upset failure (correct)

Latent failure

Complete system failure

What is the result of a latent failure due to ESD?

The component's operational life will be shortened Signup and view all the answers

Why are latent failures difficult to detect?

Because they occur after final inspection Signup and view all the answers

What type of damage can ESD cause to a component?

Direct catastrophic failures, latent failures, or upset failures Signup and view all the answers

What is the consequence of returning a component with latent failure damage to service?

The component will create more aircraft downtime and lost man-hours Signup and view all the answers

What can happen to a component that has suffered a latent failure due to ESD?

It will exhibit poor system performance over time Signup and view all the answers

What is the primary purpose of Conductive Transit Trays in an ESD workshop?

To reduce the likelihood of building up static charge during transport Signup and view all the answers

What is the only way to be certain that a component has not been subjected to ESD?

To take all precautions to avoid it Signup and view all the answers

What is the primary use of tote boxes in an ESD workshop?

To transport devices and PCBs to and from controlled static-safe workstations Signup and view all the answers

What is a common carrier used for shipment, storage, and automatic handling of Dual In-Line Packages (DIPs)?

Storage rails or tubes Signup and view all the answers

Why should you not touch the pins of any electronic component?

Because it may cause ESD damage Signup and view all the answers

What should you do when removing ESD-sensitive equipment from an aircraft?

Both A and B Signup and view all the answers

What is the purpose of an anti-static lid on a Conductive Transit Tray?

To return and reuse the tray Signup and view all the answers

What is the theory behind the shielding effectiveness of tote boxes?

More conductive material means a more efficient shield Signup and view all the answers

Why should you fit conductive covers/caps to disconnected plugs?

To prevent ESD damage Signup and view all the answers

What is the advantage of using tote boxes with lids over conductive trays alone?

They provide greater protection against static fields Signup and view all the answers

Where should ESD-sensitive equipment be opened to expose circuit cards?

At an ESD workstation Signup and view all the answers

What is the purpose of using heel grounders, ESD smocks, and ESD-safe flooring in an ESD workshop?

To reduce the likelihood of building up static charge Signup and view all the answers

What should you do when installing electronic equipment on an aircraft?

Touch the outer shell of the plug to the outer shell of the equipment mating connector Signup and view all the answers

What type of charge can be generated by friction between two objects?

Triboelectrically generated charge Signup and view all the answers

Why should electronic equipment and subassemblies be placed on a grounded anti-static mat?

To prevent ESD damage Signup and view all the answers

What is the purpose of discharging static electricity on yourself by grasping an earthed conductive surface?

To prevent ESD damage to equipment Signup and view all the answers

What is the primary purpose of ESD-safe smocks and lab coats?

To prevent static build-up on clothing Signup and view all the answers

What is the function of heel strap grounders?

To provide a conductive path to Earth Signup and view all the answers

What is the main advantage of ESD-safe work envelopes?

They reduce the risk of static electricity damage Signup and view all the answers

What is the primary benefit of using finger cots in ESD-safe areas?

They prevent static electricity damage to components Signup and view all the answers

Why are carpets and tile floors considered points of electrostatic control?

They can generate high static charges Signup and view all the answers

What is the primary purpose of workshop anti-static devices?

To protect sensitive components from damage Signup and view all the answers

What is the main feature of powder-free pink latex finger cots?

They are 3-mm thick Signup and view all the answers

What is the main benefit of using ESD-safe shoes or over-shoes?

They prevent static electricity damage to components Signup and view all the answers

Why should personnel avoid wearing synthetic clothing under their static-dissipative smocks?

Because synthetic clothing can generate static electricity Signup and view all the answers

What is the purpose of periodically monitoring ESD workstations?

To ensure all components are functional Signup and view all the answers

What is the effect of adding a small percentage of ionised air molecules?

Reducing the time for static discharge from hours to seconds Signup and view all the answers

What is the role of the high voltage in an ioniser?

To accelerate free electrons to ionise air molecules Signup and view all the answers

What is a characteristic of corona ionisers?

They utilise a step-up transformer Signup and view all the answers

Why do AC ionisers typically utilise fast airflow velocity?

To minimise recombination Signup and view all the answers

What is a limitation of using AC ionisers in a clean room environment?

They utilise fast airflow velocity Signup and view all the answers

What is the result of the interaction between free electrons and air molecules in an ioniser?

The creation of both positive and negative ions Signup and view all the answers

Study Notes

ESD Failures

Direct catastrophic failures occur when a component is damaged beyond repair, causing immediate failure.
Latent failures occur when ESD weakens or degrades a component, leading to poor system performance and eventual failure.
Upset failures occur when an ESD event causes a current flow that is not significant enough to cause total failure, but may intermittently result in gate leakage.

ESD Handling Precautions

Do not touch the pins of any electronic component.
Do not touch the sockets or pins within the plugs of any electronic equipment.
Discharge static electricity by grasping an earthed conductive surface.
When removing ESD-sensitive equipment from the aircraft, the aircraft must be grounded and power removed.
Fit conductive covers/caps to disconnected plugs.
Install electronic equipment on the aircraft by touching the outer shell of the plug to the outer shell of the equipment mating connector to equalise electrostatic potentials.

ESD Protection Devices

Conductive Transit Trays: used for transporting ESD-sensitive components in an ESD workshop, reducing the likelihood of building up static charge.
Tote Boxes: anti-static conductive boxes with lids, used for in-plant transport of devices and PCBs to and from controlled static-safe workstations.
ESD-safe finger cots: powder-free pink latex finger cots, 3-mm thickness, ideal for ESD-safe areas.
ESD-Safe Smocks and Lab Coats: minimize static build-up on normal clothing and provide a conductive path for charges to dissipate to Earth.
Heel Strap Grounders: provide a conductive path to Earth, dissipating any charge built up when walking.
ESD-Safe Work Envelopes: replace plastic envelopes, used to protect maintenance instructions and certification paperwork in ESD-safe work areas.

Workshop Anti-Static Devices

Ionisers: add equal numbers of positive and negative ions to the air, increasing electrical conductivity, and reducing static discharge time from hours to seconds.
Corona ionisers: simpler and cheaper to manufacture, use a step-up transformer to create high voltage for ion generation.
AC ionisers: produce positive and negative ions in sequence, using fast airflow velocity to minimize recombination.

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Description

This quiz covers the different types of failures that can occur due to Electrostatic Discharge (ESD) in electronic components, including direct catastrophic failures and latent failures.