After rebuilding an engine, which party is allowed to zero-time it before returning to service?

After rebuilding an engine, which party is allowed to zero-time it before returning to service?

• A. a certified repair station
• B. the engine manufacturer
• C. the aircraft owner
• D. the FAA

Answer: (B)

Zero-time means resetting the engine’s time-on-wing to zero after a rebuild, effectively treating it as a new engine for maintenance planning. This designation is controlled by the engine manufacturer because they own the official data and authority to certify that the rebuild meets their specifications. When a rebuild is performed under the manufacturer’s authority or by an authorized facility, the manufacturer can issue the zero-time status before the engine returns to service. A certified repair station can overhaul or rebuild an engine, but they don’t have the authority to unilaterally designate the engine as zero-time unless the manufacturer explicitly authorizes them to do so. The FAA regulates airworthiness, not by assigning zero-time status, and the aircraft owner cannot assign zero-time on their own.

Zero-time means resetting the engine’s time-on-wing to zero after a rebuild, effectively treating it as a new engine for maintenance planning. This designation is controlled by the engine manufacturer because they own the official data and authority to certify that the rebuild meets their specifications. When a rebuild is performed under the manufacturer’s authority or by an authorized facility, the manufacturer can issue the zero-time status before the engine returns to service.

A certified repair station can overhaul or rebuild an engine, but they don’t have the authority to unilaterally designate the engine as zero-time unless the manufacturer explicitly authorizes them to do so. The FAA regulates airworthiness, not by assigning zero-time status, and the aircraft owner cannot assign zero-time on their own.