The Cessna 172S Aircraft Flight Manual states the following for securing airplane after commencing a flight:


  1. Parking Brake -- SET.
  2. Electrical Equipment, Autopilot (if installed) -- OFF.
  3. Avionics Master Switch -- OFF.
  4. Mixture -- IDLE CUTOFF (pulled full out).
  5. Ignition Switch -- OFF.
  6. Master Switch -- OFF.
  7. Control Lock -- INSTALL.
  8. Fuel Selector Valve -- LEFT or RIGHT to prevent cross feeding.

Why can't you turn off the engine of GA aircraft like a car? Why is mixture pulled out before turning the ignition switch off?