What invalidates a Certificate of Airworthiness?

A Certificate of Airworthiness is a crucial document that confirms an aircraft's compliance with safety standards. It can be invalidated under various circumstances, but one significant factor is when the aircraft has an accident. This is because an accident typically indicates potential damage or structural failure that could compromise the safety and performance standards required for the aircraft to operate safely.

When an aircraft has an accident, it undergoes a thorough investigation to assess the extent of the damage. Depending on the findings, repairs may need to be conducted, and the aircraft must be re-evaluated to determine its airworthiness before it can fly again. Until this process is completed and the aircraft is declared airworthy, the Certificate of Airworthiness is considered invalid.

In contrast, while the other choices relate to operational aspects of the aircraft and pilot, they do not directly invalidate the Certificate of Airworthiness in the same manner. For instance, the expiration of a pilot's medical certificate affects the pilot's ability to operate the aircraft but does not impact the airworthiness of the aircraft itself.