Glossary G-1 A note on glossary terms: over the years there has been a  proliferation of aircraft weight and balance terms. This is  the result of many factors, such as the Federal Aviation  Administration (FAA) certification regulation under which  an aircraft was constructed; the FAA regulation under which  the aircraft is being operated; manufacturer standardization  agreements or a combination of these and others. Examples  of such terms areempty weight, licensed empty weight, basic  empty weight, operational empty weight, etc. as the newer aircraft, with the important exception that the  aircraft weight did not include full oil, only undrainable oil.  Mechanics and repair stations should consult the appropriate  certification rule when reestablishing empty weight 14 CFR part 121. The Federal regulations governing  domestic, flag, and supplemental operations 14 CFR part 135. The Federal regulations governing  commuter and on-demand operations. Adverse loaded CG check.  A weight and balance check to  determine that no condition of legal loading of an aircraft  can move the CG outside of its allowable limits. Many of these terms may have similar meanings or sound  similar. Pilots and aircraft mechanics must ensure they  understand the terminology and are applying the correct  values based on the procedure and situation dictating the  calculations undertaken. Aircraft specifications. Documentation containing the  pertinent specifications for aircraft certificated under CARs. Occasionally, the acronym “GAMA” follows the glossary  term. This indicates that it is part of the standardized format  adopted by the General Aviation Manufacturers Association  in 1976, known as GAMA Specification No.1. These aircraft  are usually manufactured under Title 14 of the Code of  Federal Regulations (14 CFR) part 23 and differ from aircraft  manufactured under the earlier certification rule Civil Air  Regulation (CAR) part 3 for weight and balance purposes  in the condition under which empty weight was established. Airplane Flight manual (AFM).  An FAA-approved  document, prepared by the holder of a type certificate for an  aircraft, that specifies the operating limitations and contains  the required markings and placards and other information  applicable to the regulations under which the aircraft was  certificated Aircraft certific ted under 14 CFR parts 23, 25, 27, and 29  establish their certificated empty weight as required in the  appropriate section of these regulations, which states that the  empty weight and corresponding center of gravity (CG) must  be determined by weighting the aircraft with: Approved type certificate.  A certificate of approval issued  by the FAA for the design of an aircraft, engine, or propeller. Arm.  (GAMA) The horizontal distance from the reference  datum to the CG of an item. The algebraic sign is plus (+) if  measured aft of the datum or to the right side of the center  line when considering a lateral calculation. The algebraic  sign is minus (–) if measured forward of the datum or the left  side of the center line when considering a lateral calculation. Balanced laterally.  Being balanced in such a way that the  aircraft wings tend to remain level. In contrast, aircraft certificated under the older CARs  established certifi ated empty weight under similar conditions  Ballast.  A weight installed or carried in an aircraft to move  the center of gravity to a location within its allowable limits. • Full operating flu d, including oil, hydraulic flu d,  and other fluids required for normal operation of  the aircraft systems, except potable water, lavatory  precharge water, and water intended for injection in  the engine(s). • Unusable fuel • Fixed ballast