Who is authorized to rebuild an aircraft engine and return the operating time to zero?

The only entities authorized to rebuild an aircraft engine and return the operating time to zero are the engine manufacturer or an approved overhaul facility. This requirement stems from regulations that ensure safety and reliability in airworthiness standards. Rebuilding an engine involves extensive procedures, including inspections, part replacements, and adherence to specific manufacturer standards. Only authorized facilities possess the necessary certifications, expertise, and resources to perform such intricate work.

The proper documentation and tracking of engine operating time are essential for the ongoing maintenance and operational safety of aircraft. Zeroing the operating time signifies that the engine has been completely overhauled to a condition similar to new, thereby resetting the maintenance cycle. This practice ensures compliance with regulatory standards, thereby preserving the aircraft's safety and performance capabilities.

In contrast, while mechanics, aircraft owners, and repair stations can perform various maintenance tasks, they lack the specific endorsement necessary to authorize a complete rebuild to the extent of resetting the operating time, which must be done in strict accordance with regulatory compliance and manufacturer guidelines.