EASA Part-66 Essay Questions — How They Work, with 60 to Practise

Describe the safety precautions to be observed when working on or near an aircraft oxygen system, and state the action to take if an oxygen-related fire occurs.

Describe the common classes of fire encountered in a hangar or workshop, and explain the principal fire-extinguishing agents available and their correct application to each class of fire.

Describe the operation and correct use of the micrometer and vernier caliper, and explain the care and calibration required to keep precision measuring tools accurate.

Explain the classes of fit between mating components and the meaning of clearance and interference, and describe the standard methods used to check shafts and bearings for wear and serviceability.

Describe the tools used to crimp electrical terminations in an aircraft EWIS, explain how a sound crimped joint is made, and state how a completed crimp joint is tested.

Describe the techniques used to protect and route electrical wiring within an aircraft Electrical Wiring Interconnection System (EWIS), including cable routing, looming and lacing, clamping, conduit and heat-shrink, and explain why correct routing is important to airworthiness.

Describe a solid riveted joint with reference to rivet spacing and pitch, the tools used for riveting and dimpling, and explain how a completed riveted joint is inspected.

Describe the bending and bell-forming of rigid aircraft pipes, the inspection and testing of aircraft pipes and hoses, and the correct methods of installing and clamping them.

Describe how aircraft bearings are tested, cleaned and inspected, state the lubrication requirements for bearings, and describe common bearing defects together with their likely causes.

Describe the swaging of end fittings to aircraft control cables, and explain how control cables are inspected and tested for serviceability.

Describe how a sheet metal part is marked out and formed, including the purpose of bend allowance, and explain how the finished bend is inspected.

Describe the environmental conditions that must be controlled when carrying out adhesive bonding and composite repair, and the methods used to inspect a bonded or composite structure.

Describe how an aircraft is prepared for weighing and outline the procedure used to determine its weight and centre of gravity.

Describe the safety precautions and the procedure to be followed when jacking an aircraft.

Describe the procedures and safety precautions to be observed when refuelling and defuelling an aircraft.

Describe the ground de-icing and anti-icing of an aircraft, explaining the difference between the two operations and the precautions that must be observed during the procedure.

Describe how corrosion is detected, removed, assessed and re-protected on an aircraft structure, and explain the place of visual inspection in finding such defects.

Compare dye penetrant, eddy current and ultrasonic inspection, describing the uses, advantages and limitations of each method.

Describe the inspection that must be carried out on an aircraft following a reported lightning strike or HIRF penetration, and explain why such an inspection is necessary.

Describe the content of a written maintenance report and explain the principles of effective shift and task handover communication.

Explain why human factors must be taken into account in aircraft maintenance, how human error contributes to incidents, and what is meant by Murphy's law.

Describe the limitations of human vision and explain how they affect the maintenance engineer when carrying out visual inspection, including measures that reduce the risk.

Describe the types of human memory and their limitations, and explain how these affect the aircraft maintenance engineer and how the risks can be reduced.

Explain how information processing, attention and perception work and describe their limitations and effects on the aircraft maintenance engineer.

Explain what is meant by peer pressure in the maintenance environment, why it is a hazard, and how an aircraft maintenance engineer should resist it.

Explain the importance of effective team working, supervision and leadership in an aircraft maintenance organisation, and describe how each contributes to maintaining safety and quality.

Describe the sources of stress affecting an aircraft maintenance engineer, explain how stress can degrade performance, and outline how stress can be recognised and managed.

Explain the relationship between sleep, fatigue and shiftwork for an aircraft maintenance engineer, the effect of fatigue on performance, and how the associated risks can be mitigated.

Describe the effects of alcohol, medication and drug abuse on an aircraft maintenance engineer's fitness to work, and explain the engineer's responsibilities in this area.

Explain what is meant by workload in the context of aircraft maintenance, and describe how both overload and underload can degrade an engineer's performance and how they can be managed.

Describe the principal physical-environment factors that affect an aircraft maintenance engineer, explaining how noise, illumination, climate and temperature, motion and vibration, and fumes can degrade performance and how the hazards may be controlled.

Explain the human-factors limitations associated with visual inspection and with repetitive tasks in aircraft maintenance, and describe how these limitations can be managed to maintain inspection reliability.

Describe the importance of communication within and between maintenance teams and across shift handovers, and explain the role of accurate work logging and recording in preventing maintenance error.

Explain what is meant by human error in aircraft maintenance, describe a recognised error model and the distinction between different types of error, and give examples of the types of error commonly seen in maintenance tasks.

Describe how maintenance errors can be avoided and managed, explaining the principal error-capture defences available to a maintenance organisation and the engineer.

Explain what is meant by a 'just culture' and describe the role of occurrence reporting in an aircraft maintenance organisation. Why are both essential to managing human factors and improving safety?

Describe the process of risk management in an aircraft maintenance organisation, including how hazards are identified, assessed and controlled. Explain why this is an important part of a safety management system.

What is meant by the 'Dirty Dozen' in aircraft maintenance human factors? Identify the twelve factors and explain the purpose of the concept.

Describe complacency and lack of awareness as two of the Dirty Dozen. Explain their causes, how they contribute to maintenance error, and the countermeasures that can be used to reduce them.

Describe the risk-mitigation methods and 'safety nets' that a maintenance organisation and its engineers can use to defend against the Dirty Dozen and reduce human error.

Explain the regulatory framework governing aviation safety in Europe by describing the roles of ICAO, the European Commission, EASA, and the Member States and their National Aviation Authorities, and how these bodies relate to one another.

Describe the difference between 'hard law' and 'soft law' in the EASA regulatory system, and explain the relationship between Regulations and Acceptable Means of Compliance, Guidance Material, and Certification Specifications.

Describe the categories and subcategories of the Part-66 aircraft maintenance licence and outline the certification privileges associated with each.

Explain the purpose of the Certificate of Release to Service (CRS), stating when it is required, who is entitled to issue it, and what information it must contain.

Describe the principle of basic experience requirements for obtaining a Part-66 aircraft maintenance licence and explain the recency requirements that a holder must satisfy in order to continue exercising certification privileges.

Describe the requirements an organisation must satisfy to obtain and hold a Part-145 approval, and outline the process by which that approval is granted and maintained.

Explain the role of the Accountable Manager within a Part-145 approved maintenance organisation and describe the principal responsibilities attached to the position.

Describe the purpose of the EASA Form 1 (Authorised Release Certificate) and explain when and how it is used in aircraft component maintenance.

Explain what maintenance records a Part-145 organisation is required to keep, why they are kept, and the principles governing how long they must be retained.

Describe the concept of independent certifying staff introduced by Regulation (EU) 2023/989, explaining their privileges, their responsibilities and the limitations placed on the exercise of those privileges.

Explain the purpose of the Minimum Equipment List (MEL) and the Configuration Deviation List (CDL), and describe how each is used to permit an aircraft to be dispatched.

State the documents that must be carried on board an aircraft when it is operated, and briefly explain the purpose of each.

Describe the purpose of the Aircraft Technical Log system, the information it records, and how it is used by flight crew and maintenance staff.

Explain the purpose of the Type Certificate, the Type Certificate Data Sheet (TCDS), and the Supplemental Type Certificate (STC), and the relationship between them.

Explain the purpose of the Certificate of Airworthiness, including the restricted Certificate of Airworthiness, and describe the circumstances in which a Permit to Fly is issued instead.

Explain what an Airworthiness Directive is, why compliance with it is mandatory, and describe its relationship to a manufacturer's Service Bulletin.

Describe the purpose and content of an Aircraft Maintenance Programme, and explain how it is approved and how it is amended.

Describe the role and principal responsibilities of a Part-CAMO organisation, and explain the purpose of the Airworthiness Review Certificate and how it is issued.

Explain the principles of oversight in continuing airworthiness, including the role of internal compliance monitoring within an organisation and the role of the competent authority.

Explain why information security is now a continuing-airworthiness concern and describe the Part-IS framework and the information-security management requirements placed on aviation organisations.