How long must an FAA Form 337 for the overhaul of a reciprocating engine with a planetary propeller reduction gearing be retained?

The correct answer is that the FAA Form 337 must be retained until the work is repeated or superseded by other work for a period of one year after the work is performed.

This requirement is in place to ensure that a comprehensive maintenance history is available for each engine, especially for significant alterations or repairs, such as an overhaul of a reciprocating engine with planetary propeller reduction gearing. Retaining the form for one year after the work performed allows for a review of the work done, which is crucial for maintenance accountability and safety assessments down the line.

Additionally, if the work is repeated or modified, having the prior Form 337s on file permits technicians and inspectors to reference previous repairs, making informed decisions about the current condition of the engine and any follow-up work that may be needed. This creates a clear trail of maintenance actions, ensuring compliance with FAA regulations and enhancing safety for aircraft operations.