Which block specifies the unique identification number for the aircraft?

The unique identification number for an aircraft is specified in Block 4 of the Aircraft Maintenance Form. This identification number, often referred to as the Bureau Number (BuNo) or aircraft serial number, is crucial for tracking maintenance records, flight data, and ensuring the proper identification of the aircraft within military databases.

Utilizing this number helps personnel quickly access the specific history and details of that particular aircraft, enabling effective management and operational readiness. Understanding the importance of Block 4 in identifying and managing aircraft is essential for anyone involved in aviation operations within the Navy.