Who can approve an aircraft for return to service after a 100-hour inspection has been completed?

• A. an A&P
• B. an A&P with IA
• C. the aircraft owner
• D. the design engineer

Answer: (A)

The authority to approve an aircraft for return to service after a 100-hour inspection rests with a certificated mechanic who holds an airframe and powerplant license (an A&P). This person is the one who performed or supervised the inspection and is authorized to certify airworthiness after the work. An Inspection Authorization (IA) endorsement is not required for a 100-hour release, though an IA can sign off annual or certain other inspections when applicable. The aircraft owner does not have the authority to approve return to service, and a design engineer does not certify airworthiness. So the best fit is the A&P, the certificated mechanic who performed the inspection.