7-6 Determining the CG in Percentage of Mean  Aerodynamic Chord (Percent MAC) Empty Weight CG (EWCG) Range Adverse-Load CG Checks Figure 7-6.  Weight and balance information. Figure 7-8.  Formula for determining the CG in percent MAC. Figure 7-7.  Loading conditions. Use the formula in  Figure 7-8  to determine CG in MAC percentages. This procedure is the same as found in Chapter 5, Single- Engine Aircraft Weight and Balance Computations.  Refer to the load conditions and CG information found in  Figures 7-5, 7-6,  and  7-7  to compute the CG in percent MAC: The loaded CG after alteration or repair is located at 17.9  percent MAC. The fuel tanks, seats, and baggage compartments of some  aircraft are so located that changes in the fuel or occupant  load have a very limited effect on the balance of the aircraft.  Aircraft of such a configuration show an empty weight CG  (EWCG) range in the Type Certificate Data Sheet (TCDS).  If the EWCG is located within this range, it is impossible to  legally load the aircraft so that its loaded CG falls outside  its allowable range. If the TCDS lists an EWCG range, and after the alteration is  completed the EWCG falls within this range, then there is no  need to compute a fore and aft check for adverse loading. But  if the TCDS lists the EWCG range as “None” (and most of  them do), a check must be made to determine whether or not  it is possible by any combination of legal loading to cause the  aircraft CG to move outside of either its forward or aft limits. Many modern aircraft have multiple rows of seats and often  more than one baggage compartment. After any repair or  alteration that changes the weight and balance, the Airframe  and Powerplant (A&P) FAA-certificated mechanic or  repairman must ensure that no legal condition of loading can  CG in % MAC CG in inches from LEMAC x 100 MAC = 10.42 x 100 58.0 = 17.9% MAC = CG range Datum Front seats Rear seats +74 Baggage B +116 Fuel +48.2 Baggage A +97 Forward limit Aft limit 46.0 3,200 3,000 2,800 2,600 2,400 2,200 2,000 1,800 32  34  36  38  40  42  44  46  48 Fuselage station (in) Loaded aircraft weight (lb) Airplane EW and EWCG  1,876.0 lb at +36.14 Engine METO horsepower 230 CG range  (+40.9) to (+46.0) at 3,100 lb (+33.0) to (+46.0) at 2,250 lb or less Straight line variation between points given Empty weight CG range  None Maximum weight  3,100 lb takeoff/flight 2,950 lb landing Datum to LEMAC  25.98 MAC  58.00 No. of seats  4 (2 front at +34.0) (2 rear at +74.0) Fuel capacity  92 gal (88 gal usable) two 46-gal integral tanks in wings at +48.2 See NOTE 1 for data on unusable fuel. Minimum fuel  $_{(METO HP }$÷$_{ 2) 115 lb at +48}$ Maximum baggage  160 lb Area A (100 lb at +97.0) Area B (60 lb at +116.0  Oil capacity  12 qt (−15) (6 qt usable) See NOTE 1 for data on undrainable oil. NOTE 1: The certificated empty weight and corresponding center of gravity location must include unusable fuel of 30 lb (+46) and  undrainable oil of 0 lb. The CG is +36.4 – 25.98 = 10.42 inches aft of LEMAC.  The  leading edge mean aerodynamic chord (LEMAC)  is located at station 25.98. The MAC is 58.0 inches long. The loaded CG is +36.4 inches aft of the datum.