Weight and Balance

Management of Weight and Balance Control Before any flight, the pilot should determine the weight Title 14 of the Code of Federal Regulations (14 CFR) part 23, and balance condition of the aircraft. Simple and orderly section 23.23 requires establishment of the ranges of weights procedures based on sound principles have been devised and CGs within which an aircraft may be operated safely. The by the manufacturer for the determination of loading manufacturer provides this information, which is included in conditions. The pilot uses these procedures and exercises the approved AFM, TCDS, or aircraft specifications. good judgment when determining weight and balance. In many modern aircraft, it is not possible to fill all seats, While there are no specified requirements for a pilot operating baggage compartments, and fuel tanks, and still remain within under 14 CFR part 91 to conduct weight and balance the approved weight and balance limits. If the maximum calculations prior to each flight, 14 CFR part 91, section passenger load is carried, the pilot must often reduce the fuel 91.9 requires the pilot in command (PIC) to comply with the load or reduce the amount of baggage. operating limits in the approved AFM. These limits include the weight and balance of the aircraft. To enable pilots to 14 CFR part 125 requires aircraft with 20 or more seats make weight and balance computations, charts and graphs or maximum payload capacity of 6,000 pounds or more are provided in the approved AFM. to be weighed every 36 calendar months. Multi-engine aircraft operated under 14 CFR part 135 are also required Weight and balance control should be a matter of concern to to be weighed every 36 months. Aircraft operated under 14 all pilots. The pilot controls loading and fuel management CFR part 135 are exempt from the 36 month requirement (the two variable factors that can change both total weight if operated under a weight and balance system approved in and CG location) of a particular aircraft. The aircraft owner the operations specifications of the certificate holder. For or operator should make certain that up-to-date information additional information on approved weight and balance is available for pilot use, and should ensure that appropriate control programs for operations under parts 121 and 135, entries are made in the records when repairs or modifications reference the current edition of AC 120-27, Aircraft Weight have been accomplished. The removal or addition of and Balance Control. AC 43.13-l, Acceptable Methods, equipment results in changes to the CG. Techniques and Practices—Aircraft Inspection and Repair also requires that the aircraft mechanic ensure that the weight Weight changes must be accounted for and the proper and balance data in the aircraft records is current and accurate notations made in weight and balance records. The after a 100-hour or annual inspection. equipment list must be updated, if appropriate. Without such information, the pilot has no foundation upon which to base Terms and Definitions the necessary calculations and decisions. The pilot should be familiar with the appropriate terms regarding weight and balance. The following list of terms Standard parts with negligible weight or the addition of minor and their definitions is standardized, and knowledge of these items of equipment such as nuts, bolts, washers, rivets, and terms aids the pilot to better understand weight and balance similar standard parts of negligible weight on fixed-wing calculations of any aircraft. Terms defined by the General aircraft do not require a weight and balance check. The Aviation Manufacturers Association (GAMA) as industry following criteria for negligible weight change is outlined standard are marked in the titles with GAMA. in Advisory Circular (AC) 43.13-1 (as revised), Methods • Arm (moment arm)—the horizontal distance in inches Techniques and Practices—Aircraft Inspection and Repair: from the reference datum line to the CG of an item. • One pound or less for an aircraft whose weight empty The algebraic sign is plus (+) if measured aft of the is less than 5,000 pounds datum and minus (–) if measured forward of the datum. • Two pounds or less for aircraft with an empty weight • Basic empty weight (GAMA)—the standard empty of more than 5,000 pounds to 50,000 pounds weight plus the weight of optional and special equipment that have been installed. • Five pounds or less for aircraft with an empty weight of more than 50,000 pounds • Center of gravity (CG)—the point about which an aircraft would balance if it were possible to suspend it Negligible CG change is any change of less than 0.05 percent at that point. It is the mass center of the aircraft or the Mean Aerodynamic Chord (MAC) for fixed-wing aircraft theoretical point at which the entire weight of the aircraft or 0.2 percent for rotary wing aircraft. MAC is the average is assumed to be concentrated. It may be expressed in distance from the leading edge to the trailing edge of the inches from the reference datum or in percent of MAC. wing. Exceeding these limits would require a weight and The CG is a three-dimensional point with longitudinal, balance check. lateral, and vertical positioning in the aircraft. 10-4