Federal Aviation regulation 145.59 (14 CFR – Subchapter H – Part 145) gives the following definition:
Class 1: A mechanical accessory that depends on friction, hydraulics, mechanical linkage, or pneumatic pressure for operation, including aircraft wheel brakes, mechanically driven pumps, carburetors, aircraft wheel assemblies, shock absorber struts and hydraulic servo units.
Class 2: An electrical accessory that depends on electrical energy for its operation, and a generator, including starters, voltage regulators, electric motors, electrically driven fuel pumps magnetos, or similar electrical accessories.
Gulf Aerospace holds an Unlimited Accessory Class 1 & 2 Rating issued by the Federal Aviation Administration (FAA).