Aircraft proving tests

Before a Part 121 carrier can use an aircraft type in operations, it must complete proving tests to demonstrate proficiency. For an aircraft type new to Part 121/135 operations, at least 100 hours of proving flights are required (including at least 10 hours at night), though the FAA may reduce this if proficiency is demonstrated. For each new kind of operation with an already-proven aircraft type, 50 hours of proving tests are needed. Similarly, 50 hours are required if an aircraft is materially altered—meaning different powerplant types are installed or modifications significantly affect flight characteristics.

These proving tests must include flights to representative en route airports to demonstrate real-world operational capability. During proving flights, carriers cannot carry passengers except those necessary for testing and FAA-designated personnel, though mail and cargo may be carried with approval. This ensures the carrier can safely operate the aircraft before introducing paying passengers.

*This is a plain-English summary for study only. The official 14 CFR text on this page is controlling — always read the current regulation and consult a CFI.*