Ground Support Equipment Glossary

Air Conditioning Unit

Aircraft Air Conditioning Units, also referred to as air carts, provide cold or hot air to parked aircraft. At some larger airports, individual packaged assemblies or centralized electrical-powered pre-conditioned air (PCA) systems are used.

Air Start Unit

Air start units are also commonly known as a start cart. Air starts are commonly used to start the engine of the aircraft when the APU is not operation. An air start unit can also be used with the aircraft’s engine does not have on-board APU. Air start units normally working by having between one to three hoses connected to the aircraft and the air start. The air start creates a very high pressure of air in order to start the aircraft engine. The number of hoses that an aircraft will require varies on the type of aircraft with larger aircrafts requiring up to three hoses.

Aviation Fuel Trucks

Aircraft fuel trucks can be either self-contained vehicles or mobile carts. Since aircraft fuel needs are so massive, refueler trucks often carry up to 10,000 gallons of fuel. Smaller carts are used with a hydrant system which connects to a refueler truck and can simplify refueling logistics for airports by providing more refueling options from one truck.

Baggage Tugs

Baggage tugs or baggage tractors are also commonly known as cargo tractors. They are designed to transport cargo and baggage carts on the airport tarmac. Unlike aircraft tractors, baggage tugs normally lack all-wheel drive. Most baggage tugs have a drawbar pull between 3,000-8,000 lbs. Bag tugs may have the ability to move certain ground support equipment as well including aircraft air conditioning units, airstart units, and ground power units and others on the airfield.

Belt Loaders

Belt loaders are a type of powered equipment with a conveyor belt that is often used for the purpose of loading and unloading baggage and cargo to and from the aircraft. The belt loader is normally positioned to have one end at the door sill of an aircraft to load or unload cargo from the aircraft. There are various types of belt loaders including gas belt loader, walk behind belt loader, and an electric belt loader. Belt loaders can be used for a wide variety of different aircrafts.

Bobtail Tractor

A bobtail tractor can be used to haul baggage or dollies over long distances. The chassis of the vehicle often are comprised of a Ford chassis. Bobtails are mainly used for cargo hauling purposes. They are primarily used to tow multiple dollies at high speeds ensuring efficiency and safely.

Cargo Loaders

Cargo loaders, or k-loaders, are used in the aviation industry for the purpose of loading and unloading cargo containers and pallets into and out of aircrafts. Cargo loaders come in different sizes customized based on the aircrafts they will be used with. Cargo loaders normally have two different platforms that ascend and descend independently of each other. Cargo pallets from the aircraft are transported onto a cargo loader with the assistance of built-in rollers on the cargo loader. Once cargo has been brought onto the platform, the platform with descend to the height needed by the operation. There are various container and pallet loaders available. Some of the most common categories include standard, universal, and wide.

Catering Truck

Catering Trucks are generally operated by airlines and compaines that specialize in airline catering (e.g. preparing and supplying packaged food). Catering vehicles are used to facilitate the unloading and reloading of food and beverages for passengers and crew. Meals served on airplanes are typically delivered using these standardized catering vehicle carts.


Dollies are used for transporting baggage and cargo between the aircraft and the terminal or sorting facility. As a standard safety feature, dollies normally come with a brake system the prevents the wheels from moving unless a tug is attached to the rod of a dolly. Dollies can have various specialized features including rollers to assist in the moving of containers or pallets. They can also have a revolving platform to facilitate the rotating of ULDs in the correct position. Lastly, many dollies can also have brakes that automatically lock depending on whether the rod is in the vertical orientation (parked) or automatically release when the towbar is in the horizontal orientation (towing).

Ground Power Unit (GPU)

Ground power units (GPU) are used to supply power to aircrafts that are parked on the ground. Most ground power units provide 28V of direct current (DC) or 115V 400 Hz of alternating current to aircrafts. The electrical energy is carried from a generator to a connection on the aircraft via an insulated cable that is capable of handling 90 kVA. The alternating current (AC) GPU normally runs in the 400 Hz band and can be used for larger aircrafts including commercial airlines.

Mercury GSE offers many different types of GPU for aircraft, including solid state, diesel, and gas powered GPU.

Ground Support Equipment

Ground support equipment refers to the equipment that is used to support aircrafts in between flights. It can normally be found on airports, MRO facilities, or anywhere aircrafts are parked on the ground. The main purpose of ground support equipment is to ensure the safe operations of an aircraft in between flights. Ground support equipment assists with all airport operations including transporting aircrafts, baggage, cargo, and people. Ground support equipment can be operated by leading airlines, airports, ground handlers, and cargo companies. It can involve a variety of equipment to provide ground power and air conditioning, moving an aircraft, servicing an aircraft, loading / unloading passengers, loading and unloading baggage and cargo, and servicing the airport's ramps, runways, and other areas.


Aircraft heaters provide hot air to different sized aircrafts. There are different sized heaters that are available on the market depending on the type of aircraft that they will be used for.

Lavatory Service Vehicles

Lavatory service vehicles are used to empty and refill lavatories that are onboard aircrafts. Lavatory waste is stored onboard an aircraft in tanks until aircrafts have been grounded. Once grounded, tanks are emptied with the assistance of lavatory service vehicles. Then, a fluid known as “blue juice” is ran through the tank. This formula is a mixture of a disinfecting concentrate along with water to ensure the aircraft tank has been thoroughly cleaned.

View our selection of service vehicles.

Passenger Boarding Stairs

Whether towed, pushed into position, or fixed to a truck, boarding stairs provide a means of loading and unloading passengers at hardstands (remote parking positions) and in the absense of jet bridges. Passenger boarding stairs are a mobile staircase designed to allow passengers and crew access to the aircraft doors. Most commercial aircraft have door sills 5 0 20 feet high, requiring stairs for safe access to the cabin and cockpit. Small passenger boarding steps can be pushed or towed by a number of different vehicles, but larger passenger boarding stairs are self-powered units. More sophisticated units offer adjustable height to accomodate a large range of commercial and private aircraft.

Potable Water Service Vehicles

Potable water trucks are used to deliver safe drinking water to an aircraft. These specialized vehicles store filtered, potable water to be delivered to aircraft as needed. These trucks utilize a pump to push the water from the truck to the airplane. 

Pushback Tractors

Pushback tractors are used to tow aircrafts that are on the ground. Some common uses of pushback tractors include moving aircrafts to and from the terminal gate when an aircraft is ready to fly or has just landed. They can also be used to tow aircrafts to a hangar. The size of a pushback tractor depends heavily on the type of aircraft that will be towed. There is also a variation in pushback tractors based on requiring a tow-bar to be connected to the aircraft, or a towbarless pushback tractor. Towbarless pushback tractors work by lifting the nose gear of the aircraft off the ground to make it easier to tow or push.

Water Service Vehicles

Water service vehicles in the aviation industry are special vehicles that provide filtered water to an aircraft. Although this water is filtered, it is not-potable water. This means, it is not intended for consumption. The water from these water service vehicles is normally used in aircraft sinks. There is normally a pump in the vehicle that assists the water to flow from the vehicle into the aircraft safely. Once the water is in the aircraft, it is stored safely away from potential contaminants.