ATA 28 Fuel System Components Quiz

Fuel Types

• Gasoline is composed of iso-octane and heptane
• Kerosene is composed of hydrocarbons with a higher sulfur content
• Avgas is gasoline-based, better at cold weather, and more volatile
• Jet Fuel is kerosene-based, with a higher energy content per weight, and is not flammable or explosive at normal temperatures

Avgas and Jet Fuel Types

• Avgas 80: a mixture of 80% iso-octane and 20% heptane
• Avgas 100: has anti-knock properties as pure iso-octane
• Avgas 100LL: same as Avgas 100 but with less lead
• Jet A: has a freeze point of -40°F (-40°C)
• Jet A-1: has a freeze point of -52.6°F (-47°C)
• Jet B: a mixture of gasoline and kerosene, with a freeze point of -58°F (-50°C)

Fuel Tank Locations

• Rigid removable tanks: typically made of metal, plastic, or fiberglass, and must be held down with straps on the aircraft structure
• Integral fuel tanks: areas inside the aircraft structure sealed for fuel storage, with inspection panels for internal inspection and servicing
• Bladder fuel tanks: reinforced rubberized bags installed in a section of aircraft structure, designed to accommodate fuel

Fuel System Components

• Fuel pump: delivers a properly pressured, continuous supply of fuel, and can be driven manually, electrically, or engine-driven
• Fuel gauge: indicates the amount of fuel measured by a sensing unit in each fuel tank, and is displayed in gallons or pounds
• Valves: installed in the fuel system to provide a means for shutting off fuel flow, for tank and engine selection, for crossfeed, and for fuel transfer
• Fuel primer: used to draw fuel from the tanks to vaporize fuel directly into the cylinders prior to starting the engine

Hydraulics

• Pascal's Law: F1 = F2, P1A1=P2A2
• Hydraulic system advantages: ease of transmitting force over large distances, and mechanical advantage achieved through a larger output piston
• Hydraulic fluid: must flow through lines with minimal opposition, be incompressible, and have good lubricating properties

Flight Controls

• Secondary control surfaces: turns, slipping turns, and skidding turns
• Trimmable horizontal stabilizer: helps with rate of turn and bank angle

Fuel System Purpose

• Primary purpose: supplies fuel to engines and APU, controls and monitors fuel quantity, and controls fuel transfer to maintain C.G limits
• Secondary purpose: keeps fuel in the outer wing for wing bending and flutter relief, and cools oil inside the engine