An electrical system failure (battery and alternator) occurs during flight. In this situation, you would

• A. Lose engine power
• B. Experience avionics equipment failure
• C. Lose cabin pressurization
• D. Lose the ability to control rudder

Answer: (B)

A loss of electrical power from a failed battery and alternator means all electrically powered systems stop functioning, so avionics equipment would fail. In most light general aviation airplanes, the engine ignition is driven by magnetos and does not depend on the electrical system, so engine power is not automatically lost with an electrical failure. Cabin pressurization is not a factor in unpressurized light aircraft, and rudder control is a mechanical input through the rudder pedals, not an electrical system dependency in these aircraft. So the observable consequence of this failure is the loss of avionics equipment, and you’d continue by relying on non-electrical instruments and standard flight procedures.