Final answer:
The three-digit code is known as an Air Force Specialty Code (AFSC), used by the United States Air Force to identify personnel with special training or experience to meet contingency and base-level requirements.
Step-by-step explanation:
A three-digit code that identifies personnel with special training or experience to meet contingency and base-level requirements is referred to as an Air Force Specialty Code (AFSC) in the United States Air Force. This code is akin to Military Occupational Specialties (MOS) in the Army and Marine Corps or ratings in the Navy and Coast Guard.
These codes are used to align personnel with jobs that match their skills and qualifications. It is vital for personnel managers and the individuals themselves in ensuring that the right people are positioned in the appropriate roles, particularly during times of contingency operations or specific mission requirements at military installations.