Final answer:
Specifications for aircraft identification numbers are found in Part 45 of the Federal Aviation Regulations, detailing size, location, and characteristics required for regulatory compliance.
Step-by-step explanation:
Aircraft mechanics can find the specifications for the identification numbers that must be displayed on an aircraft (a/c) in the Federal Aviation Regulations (FARs), specifically in Part 45 – Identification and Registration Marking.
This part of the regulations outlines the requirements for size, location, and characteristics of the registration numbers that need to be prominently displayed on the exterior of the aircraft. The purpose of these identification numbers is to allow for easy recognition and registration of the aircraft by aviation authorities.