How many copies of FAA Form 337 are typically prepared when required, and what is their distribution?

When FAA Form 337 is required, two signed copies are typically prepared. One copy is given to the owner of the aircraft, providing them with documentation of the major repair or alteration performed. The second copy is submitted to the local FAA Flight Standards District Office (FSDO) to ensure that the FAA is informed of the changes made to the aircraft. This process is crucial for maintaining accurate records and ensuring compliance with regulations regarding alterations to the aircraft's structure, systems, or components. Proper distribution and documentation are essential for maintaining the airworthiness of the aircraft and for future reference during inspections or regulatory checks.