# Weight Weight is one of the most important factors considered from the time the aircraft is designed until it is removed from service. It is of prime importance to the manufacturer through all phases of production and must remain foremost in the pilot's mind when planning and performing missions. Changes in basic aircraft design weight, either in initial production or subsequent modifications by maintenance activities, have direct bearing on aircraft performance. Cargo/troop loading and aircraft gross weight must be examined closely by the pilot as these factors may determine the safety and success of a mission. Gross weight limitations have been established and are in applicable operator's manuals. *** ## **Weight Definitions** The following weight terms and definitions aid aviators in pre-mission planning. Be aware that some weight and balance forms may not include one of the weight profiles in this section. Careful examination is required to avoid inaccurate computations. *** ### **Empty Weight** Empty weight is used for design purposes and usually does not affect service activities. Empty weight includes aircraft structure weight plus—communications, control, electrical, hydraulic, instrument, and power plant systems; furnishings; anti-icing equipment; auxiliary power plant; flotation landing gear; and armament, anchor, and towing provisions. *** ### **Basic Weight** Basic weight of an aircraft is weight including all hydraulic and oil systems full, trapped and unusable fuel, and all fixed equipment. From basic weight total, it is only necessary to add crew, fuel, cargo, and ammunition (if carried) when determining the aircraft’s gross weight. Basic weight varies with structural modifications and changes of fixed aircraft equipment. *** ### **Operating Weight** Operating weight includes basic weight plus aircrew, aircrew's baggage, emergency gear, and other equipment required. Operating weight does not include weight of fuel, ammunition, bombs, cargo, or external auxiliary fuel tanks if such tanks are to be disposed of during flight. *** ### **Gross Weight** Gross weight is total weight of an aircraft and its contents. *** ### **Takeoff Gross Weight** Takeoff gross weight includes operating weight plus fuel, cargo, ammunition, bombs, auxiliary fuel tanks, and other material carried. *** ### **Landing Gross Weight** Landing gross weight is takeoff gross weight minus items expended during flight. *** ### **Useful Load** Useful load is the difference between empty and gross weight and includes fuel, oil, crew, passengers, cargo, and other material carried. *** ### **Total Aircraft Weight** Total aircraft weight includes the sum of operating weight and weight of takeoff fuel. *** ## **Weight Versus Aircraft Performance** Specific weight limitations of an aircraft cannot be exceeded without compromising safety. Overloading an aircraft may cause structural failure or result in reduced engine and airframe life. An increase in gross weight affects the aircraft’s performance as follows: * Increases takeoff distance. * Reduces hover performance. * Reduces rate of climb. * Reduces cruising speed. * Increases stalling speed in FW aircraft. * Decreases retreating blade stall speed (RW). * Reduces maneuverability. * Reduces ceiling. * Reduces range. * Increases landing distances. * Promotes instability. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://229.gitbook.io/229-hub/knowledge/army-aviation-fundamentals/weight-balance-and-loads/weight.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.