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helps with balloon landings and cushions some of the impact force at landing. The basket contains the fuel tanks, instruments, pilot, and passengers. 

Aluminum, stainless steel, or flexible nylon poles (in conjunction with stainless steel cables) located on the upper portion of the structure transfer the basket load to the envelope attachment points and support the burner assembly. Quick pins or aircraft bolts connect the support tubes, with nylon rods usually inserted into the sockets, and the cables attached around them. Lower frame tubes support the floor, permitting the floor load to be transferred to the lower frames. Oak skids, usually affixed to the floor, add rigidity and provide a point of abrasive resistance to the floor. Rattan sidewalls of varying thickness, design, and color surround and protect the passengers, equipment, and fuel tanks. Larger baskets, usually found on large ride balloons, may have padded basket dividers to form passenger compartments. 

## Instruments 

As required by 14 CFR part 31, balloons are equipped with an altimeter, a rate of climb indicator, fuel quantity gauges, and an envelope temperature gauge. Many newer balloons use some type of electronic instrument system, but older balloons may still be equipped with traditional, pressure driven analog instruments. 

The most common arrangement of instruments is a small pod or package which includes the altimeter, rate of climb indicator (variometer or vertical speed indicator), and the envelope temperature gauge (pyrometer). A cable is plugged into the instrument package during the preflight or layout process which connects to a sensor located in the top of the balloon and operates the envelope temperature gauge. Fuel quantity gauges, located on the top portion of each fuel tank, provide a reference for the quantity of fuel remaining in the tank. As these gauges are mechanical, they are sometimes inaccurate, and in most configurations do not read from 0 to 100 percent. This needs to be taken into consideration during the flight planning process. 

In recent years, many manufacturers have added a wireless system that transmits the temperature signal to a receiver in the basket via a radio or infrared signal. This eliminates the necessity of a wire being located in the balloon envelope. These instrument systems are popular, but have reliability issues because radio interference or the thermal “plume” from the burner can degrade the signal transmission. 

## Fuel Tanks 

Balloons generate heat through the use of propane. The propane is contained in aluminum or stainless steel tanks mounted inside the basket. These tanks may be either 

vertical or horizontal, and contain 10, 15, or 18 gallons of propane. Larger tanks are available for larger ride balloons. [Figure 2-10] 

The tanks, sometimes referred to as pressure vessels, are commonly equipped with a service valve (or main liquid valve), a fixed maximum liquid level gauge (or “spit valve”), a float gauge, and a pressure relief valve. The service valve regulates the flow of the liquid propane to the heater. The fixed maximum liquid level gauge provides an indication that the tank is filled to its maximum design quantity, or 80 percent of the total capacity of the tank. The float gauge provides a reading of the remaining capacity of the tank in a percentage. The pressure relief valve allows for the release of propane from the tank should the tank exceed the maximum design pressure. A pressure relief valve normally releases at 375 pounds per square inch (psi). Figure 2-11  provides additional information on propane management. 

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