Inspect aircraft, maintenance procedures, air navigational aids, air traffic controls, and communications equipment to ensure conformance with federal safety regulations.

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.

Operate and watch over bridges, canal locks, and lighthouses to permit marine passage on inland waterways, near shores, and at danger points in waterway passages. They supervise such operations. Includes drawbridge operators, lock operators, and slip bridge operators.

Supervise and coordinate activities of crew engaged in operating and maintaining engines, boilers, deck machinery, and electrical, sanitary, and refrigeration equipment aboard ship.

Operate small motor driven boats. They assist in navigational activities.

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.

Supervise or coordinate activities of crew aboard ships, boats, barges, or dredges.

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