Airworthiness of Aircraft
The concept
Airworthiness is the fitness of an aircraft to fly safely, established through type certification, production approval and continuing airworthiness. ICAO Annex 8 sets the minimum standards; States issue Certificates of Airworthiness (C of A) based on their own codes (e.g. EASA, FAA). Know the difference between a type certificate (design), a certificate of airworthiness (individual aircraft, validity period) and a permit to fly (for aircraft not meeting full requirements).
Continuing airworthiness
Maintenance programmes, airworthiness directives (mandatory), service bulletins (usually advisory) and the mass and balance/performance limitations are all part of airworthiness. An aircraft must be maintained in accordance with an approved programme and released to service by appropriately authorised personnel. The C of A remains valid only while maintenance, modifications and inspections comply with the approved schedule.
Traps
- Confusing airworthiness with registration: both are separate documents.
- Assuming a C of A never expires - validity depends on State rules and continued compliance.
- Confusing an airworthiness directive (mandatory) with a service bulletin (manufacturer recommendation).
- Forgetting that modifications require approval; unapproved changes invalidate the C of A.
Worked example
An aircraft has a valid C of A but a new airworthiness directive requires inspection within 10 days. The C of A does not automatically lapse, but operating past the AD compliance date renders the aircraft unairworthy. Rule of thumb: ADs are law; SBs are advice.
Exam rule
If asked who is responsible for airworthiness, the answer is normally the operator/owner for continued compliance, while the State of registry issues and can suspend the C of A.