Locking Devices in Aircraft Maintenance

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Questions and Answers

What is the primary purpose of locking devices in aircraft?

To improve the aesthetics of the assembly

To prevent nuts and bolts from loosening due to vibration (correct)

To facilitate quick repairs

To increase the weight of the component

Which type of self-locking nut is constructed without the need for additional safetying means?

Fiber-lock type nut (correct)

Castellated nut

All-metal type nut (correct)

Locking mechanism nut

What is the function of plain washers in aircraft repair?

To increase surface area for heat dissipation

To secure a nut in place against lateral movement

To prevent vibration loosening

To provide a smooth bearing surface and act as a shim (correct)

What is the characteristic feature of shakeproof lock washers?

They incorporate a spring action to prevent loosening. Signup and view all the answers

Which of the following is NOT a type of fastener mentioned for aircraft panel access?

Quick-connect fasteners Signup and view all the answers

In what scenario would special washers be necessary during an aircraft repair?

When installing bolts at an angle to a surface Signup and view all the answers

What distinguishes split pins from other locking methods?

They fit into drilled holes of castellated nuts and are used only once. Signup and view all the answers

Why is it important to use plain washers under lock washers?

To avoid damage to the surface material Signup and view all the answers

What is necessary to ensure safe movement of an aircraft on the ground?

Consultation of manufacturer manuals for procedures Signup and view all the answers

Which individuals are essential for the movement of an aircraft?

A person at each wing tip and one at the tail Signup and view all the answers

Which precaution is NOT required for safe aircraft ground running?

Ground support equipment must be kept close to the aircraft Signup and view all the answers

What is the minimum requirement for personnel during aircraft towing?

At least one qualified cockpit operator and a vehicle driver Signup and view all the answers

What should be ensured regarding rotors or propellers during aircraft ground operations?

Proper safety measures must be in place to avoid injury Signup and view all the answers

What is a critical consideration before moving an aircraft?

All foreign object debris (FOD) should be removed Signup and view all the answers

Which is a necessary requirement when preparing for aircraft ground running?

All personnel must wear protective gear Signup and view all the answers

When should wheel chocks be available during aircraft operation?

In case of a brake system failure Signup and view all the answers

Why is water ineffective for extinguishing certain types of fires?

It reacts with metal to cause explosions. Signup and view all the answers

Which extinguishing agent is effective against combustion because it displaces oxygen?

Carbon dioxide Signup and view all the answers

What is a disadvantage of using dry chemical extinguishers?

They leave a residual dust that obstructs vision. Signup and view all the answers

Which extinguishing agent is no longer approved due to its toxicity and potential to produce poisonous gas?

Carbon tetrachloride (Halon 104) Signup and view all the answers

What requirement must portable fire extinguishers meet in aircraft crew and passenger compartments?

They must minimize the hazard of toxic gases. Signup and view all the answers

Why might methyl bromide (Halon 1001) not be used in aircraft?

It cannot be used in confined spaces due to its toxicity. Signup and view all the answers

What is the consequence of using soda acid extinguishers in certain situations?

They can cause corrosion to adjacent materials. Signup and view all the answers

Which fire extinguishing agent chemically reacts with flames to extinguish fires?

Halogenated hydrocarbons Signup and view all the answers

What is the primary purpose of housekeeping fire prevention methods in aircraft maintenance areas?

To minimize the effects of a fire through effective servicing Signup and view all the answers

When cleaning up flammable liquid spills in aircraft environments, what is the recommended action?

Investigate and clean up immediately Signup and view all the answers

Why must oil and greases not be used on oxygen equipment in aircraft?

They increase the potential for spontaneous combustion Signup and view all the answers

What is essential to observe when working near aircraft to prevent fire hazards?

Avoid naked lights and recognize sealed light units Signup and view all the answers

What should be done with rags that are impregnated with flammable fluids?

They must be kept in a metal container with a lid Signup and view all the answers

Before commencing work on an aircraft, what should a technician always consult?

The applicable aircraft manuals for fire fighting procedures Signup and view all the answers

How are fire extinguishers generally activated in aircraft maintenance areas?

By pulling a safety pin and striking a button Signup and view all the answers

What must be strictly followed regarding oxygen systems in aircraft?

The regulations for storage, servicing, and installation must be observed Signup and view all the answers

What is the primary reason for using a shadow board for handtools?

To help with organization and daily tool checks Signup and view all the answers

Which type of spanner is recommended to reduce slippage when tightening nuts or bolts?

Ring and socket spanner Signup and view all the answers

What should be done with punches that have mushroom heads?

They should be kept in their original shape Signup and view all the answers

What must be ensured before using powered tools?

All guards and fences are securely installed Signup and view all the answers

When using pliers to clip wire, what is the correct practice for deflection of the wire?

Deflect the wire towards the ground Signup and view all the answers

What is an essential feature of screwdrivers used for electrical work?

They require an insulated handle Signup and view all the answers

Which of the following practices is advised for using hammers?

Loose fitting hammer heads should be avoided to prevent flying off Signup and view all the answers

What is the best practice when using a spanner to tighten a bolt or nut?

Pull the spanner whenever possible instead of pushing Signup and view all the answers

Study Notes

Locking Devices

Locking devices prevent nuts and bolts from loosening due to vibrations in aircraft.
Common locking methods include split pins, lock nuts, and wire-locking.

Self-Locking Nuts

Self-locking nuts integrate safety features within their construction.
Two types: all-metal and fibre-lock nuts require no additional safetying mechanisms.

Aircraft Washers

Types: plain, lock, and special washers are used in aircraft repair.
Plain washers act as shims and protect surfaces under lock washers.
Lock washers use spring action to prevent nut loosening from vibration.
Shakeproof lock washers feature tabs for securing nuts and bolts.
Special washers are designed for bolts installed at angles or for alignment purposes.

Turn Lock Fasteners

Known as quick-release or quick-action fasteners, facilitating easy access for inspections.
Common types: Dzus, Camloc, and Airloc fasteners.

Split Pins (Cotter Pins)

Used with castellated nuts designed for drilled bolts.
Split pins must fit snugly in holes and are single-use.
Rotor systems generally have specific locking procedures outlined in manufacturer manuals.

Movement of Aircraft

Aircraft can be ground-handled or towed for servicing or flight.
Locking devices must be in place according to manufacturer manuals.
Wheel chocks should be available in case of brake failures.
A minimum ground crew includes a qualified driver, cockpit operator, and wing-tips watchers.

Aircraft Ground Running

Only qualified personnel may perform ground running of aircraft.
Ground procedure manuals should guide practices and precautions.

General Precautions

Ensure aircraft are on firm ground, free from foreign object debris (FOD).
Ground support equipment must be away from the aircraft.
Aircraft should face into the wind for optimal airflow.
Main wheels must be chocked with the parking brake engaged.
Warning against water on metal fires; alternative methods: CO, HALON, dry chemicals.

Aircraft Fire Extinguishers

Built-in detection and extinguishing systems meet FAA, CAA, and DCA regulations.
Portable extinguishers must be type-approved, suitable for specific fire risks, and minimize toxic hazards.

Extinguishing Agents Not Recommended

Dry chemical extinguishers: Effective but leave residue harmful to visibility and equipment.
Carbon tetrachloride (Halon 104): Toxic and no longer approved due to gas toxicity when heated.
Soda acid and foam extenders can be both toxic and corrosive.
Methyl bromide (Halon 1001): Highly toxic and corrosive to several metals.
Chlorobromomethane (Halon 1011): Effective but also toxic.

Fire Fighting Appliances

Local firefighting equipment requires knowledge of extinguisher locations and emergency exits.
Fire prevention through efficient servicing and prompt first aid firefighting equipment use.

Aircraft Fire Hazards

Flammable liquids such as fuels and hydraulic oils need immediate cleanup upon spillage.
Extra precautions during defueling due to high fire risk.

Oxygen Systems

High-pressure cylinders store oxygen and must be leak-free to prevent fire escalation.
Oil and grease must never contact oxygen equipment.

Cleaning Materials

Avoid accumulation of waste fluids; use closed metal containers for contaminated rags.

Naked Lights and Heat Sources

Avoid naked flames and unsealed light sources around aircraft.
Smoking prohibited near aircraft, hangers, and fuel zones.

Aircraft Fire Extinguishing Procedure

Always refer to aircraft manuals before commencing work to ensure adherence to firefighting procedures.

Hand Tools

Tools should be organized and easily checked using shadow boards.
Strict rules for the use of hammers, screwdrivers, punches, and spanners to prevent accidents.

Powered Tools

Ensure all safety guards are in place before use.
Protective clothing is essential to avoid contact with moving parts.

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Description

This quiz explores various locking devices used in aircraft to prevent nuts and bolts from loosening due to vibrations. It covers methods such as split pins, lock nuts, wire-locking, and the role of self-locking nuts in ensuring safety. Test your knowledge on these crucial components of aircraft maintenance!