What are the purposes of fuel selector valves?

• A. To provide a means for shutting fuel flow off, tank and engine selection, crossfeed, and fuel transfer
• B. To filter the fuel before injection
• C. To regulate the air-fuel mixture
• D. To measure fuel level in tanks

Answer: (A)

Fuel selector valves are there to control where the engine’s fuel comes from and how it is distributed among tanks. They provide an on/off shutoff for emergency or maintenance, let you choose a single tank or feed from both tanks, and enable crossfeed so fuel can flow from one tank to another or to the engine if one tank is low or empty. Some systems also include a transfer function to move fuel between tanks to maintain balance or ensure a steady supply. These functions help keep the engine fed and the airplane balanced, and they’re separate from filters, which clean the fuel, or the devices that regulate the air-fuel mixture or measure fuel level.