What is the status of a flight engineer certificate unless suspended or revoked?

A flight engineer certificate is issued indefinitely, meaning that as long as it is not suspended or revoked, it remains valid for the holder's lifetime. This reflects the regulatory framework that recognizes the qualifications and training of flight engineers, allowing them to maintain their credentials without the pressure of a specific expiration timeline. The status of these certificates provides stability in workforce qualifications, allowing flight engineers to remain compliant without frequent renewals.

Other options suggest limitations on the validity of the certificate, such as specific expiration dates or mandatory renewals, but the indefinite nature of the certification emphasizes the trust in the skill and ongoing competency of the flight engineer as long as regulatory standards are adhered to.