Operate and monitor communications, detection, and weapons systems essential for controlling air, ground, and naval operations.

Direct the operation of tanks, light armor, and amphibious assault vehicle units during combat situations on land or in aquatic environments.

Operate and maintain catapults, arresting gear, and associated mechanical, hydraulic, and control systems involved primarily in aircraft carrier takeoff and landing operations.

Provide services to ensure the safety and comfort of passengers aboard ships, buses, trains, or within the station or terminal. They perform duties such as greeting passengers, explaining the use of safety equipment, serving meals or beverages, or answering questions related to travel.

Conduct field studies to determine traffic volume, speed, effectiveness of signals, adequacy of lighting, and other factors influencing traffic conditions, under direction of traffic engineer.

Service automobiles, buses, trucks, boats, and other automotive or marine vehicles with fuel, lubricants, and accessories. They collect payment for services and supplies. They lubricate vehicle, change motor oil, install antifreeze, or replace lights or other accessories, such as windshield wiper blades or fan belts. They repair or replace tires.

Park vehicles or issue tickets for customers in a parking lot or garage and collect fee.

Steer ships into and out of harbors, estuaries, straits, or sounds, or on rivers, lakes, or bays. They must be licensed by the coast guard with limitations indicating class and tonnage of vessels for which license is valid and route and waters that may be piloted.

Command vessels in oceans, bays, lakes, rivers, or coastal waters.

Operate subway or elevated suburban trains with no separate locomotive, or electric powered streetcar, to transport passengers. They handle fares.