Plain English Meaning

The rules that say what the airplane can and cannot do safely. Things like the fastest you can fly, the most weight it can carry, what kind of weather you're allowed to fly it in, and what maneuvers are permitted. These come from the manufacturer, are approved by the FAA, and the pilot must follow them.

Full Definition

The operating boundaries established by the manufacturer and approved by the FAA within which an aircraft must be operated. These include airspeed limits, weight and balance limits, powerplant limits, maneuvering limits, and approved kinds of operation. They are published in the Pilot's Operating Handbook (POH) or Airplane Flight Manual (AFM) and are legally binding on the pilot.