Airworthiness, Inspection and Quality Assurance
What you must understand
Airworthiness is a continuing state, not a one-off certificate. Know the difference between initial airworthiness (type certificate, certificate of airworthiness issue) and continuing airworthiness (maintenance programme, airworthiness directives, service bulletins, repairs and modifications, and the airworthiness review). Understand the mandatory nature of an airworthiness directive and the non-mandatory nature of a service bulletin unless it is adopted by the regulator or the operator's programme.
Know the inspection concepts: scheduled versus unscheduled, the meaning of a check cycle, sampling inspection, and the role of nondestructive testing (visual, dye penetrant, magnetic particle, eddy current, ultrasonic, radiography) and which material each suits. Understand the quality system: the quality manual, audit, corrective action, and the independence of the quality function from production. Know the meaning of a finding, an observation and a non-conformance, and how a corrective action closes a finding.
Traps
Questions often ask whether a service bulletin is mandatory - the answer is normally no unless mandated. Another trap is confusing an audit finding with an observation, or assuming the quality manager reports to the production manager.
Worked example
A manufacturer issues a service bulletin recommending replacement of a component. It becomes mandatory only when the regulator issues an airworthiness directive or the operator's approved maintenance programme adopts it. Until then, it is a recommendation, and the engineer records the decision.