How many months must completed functional check flights be retained in the aircraft maintenance file at a minimum?

The requirement to retain completed functional check flights in the aircraft maintenance file for a minimum of six months is outlined in aviation regulations that govern maintenance record-keeping practices. This duration ensures that records are accessible for audit and review purposes, which is critical for maintaining the safety and airworthiness of the aircraft.

Retaining records for six months allows for adequate time to catch any discrepancies that may arise during the operational use of the aircraft that could relate to the checks performed. It provides assurance of ongoing compliance with maintenance protocols and regulatory requirements, as well as supporting investigations in the case of incidents or safety evaluations.

A period shorter than six months may not provide sufficient time for issues to manifest, while a longer period, although helpful, may not be specifically mandated by regulations for functional check flights, leading to potential inefficiencies in record management. This structured retention period strikes a balance between regulatory compliance and operational efficiency.