of equal weight. Instead, do a full computation of all items  to be loaded on the aircraft, including baggage, as well as  the pilot and passenger. It is recommended that all bags be  weighed to make a precise computation of how the aircraft  CG is positioned.  The importance of the CG was stressed in the discussion  of stability, controllability, and performance. Unequal load  distribution causes accidents. A competent pilot understands  and respects the effects of CG on an aircraft.  be converted to fps by multiplying it by a constant of 1.69.  Therefore, an aircraft traveling at 120 knots (TAS) travels  at 202.8 fps. Knowing the speed in fps (202.8) multiplied by  the time an aircraft takes to complete a circle (68.6 seconds)  can determine the size of the circle; 202.8 times 68.6 equals  13,912 fGLYPH<df00>GLYPH<df00>t. Dividing by π yiGLYPH<df00>lds a diamGLYPH<df00>tGLYPH<df00>r of 4,428 fGLYPH<df00>GLYPH<df00>t,  which when divided by 2 equals a radius of 2,214 feet  [Figure 5-61],  a foot within that determined through use of  the formula in  Figure 5-59.  Weight and balance are critical components in the utilization  of an aircraft to its fullest potential. The pilot must know  how much fuel can be loaded onto the aircraft without  violating CG limits, as well as weight limits to conduct  long or short flights with or without a full complement of  allowable passengers. For example, an aircraft has four seats  and can carry 60 gallons of fuel. How many passengers can  the aircraft safely carry? Can all those seats be occupied at  all times with the varying fuel loads? Four people who each  weigh 150 pounds leads to a different weight and balance  computation than four people who each weigh 200 pounds.  The second scenario loads an additional 200 pounds onto the  aircraft and is equal to about 30 gallons of fuel.  In  Figure 5-62,  the pilot enters a canyon and decides to turn  180° to exit. The pilot uses a 30° bank angle in his turn.  The additional weight may or may not place the CG outside  of the CG envelope, but the maximum gross weight could  be exceeded. The excess weight can overstress the aircraft  and degrade the performance.  The aircraft’s weight and balance data is important  information for a pilot that must be frequently reevaluated.  Although the aircraft was weighed during the certification  process, this information is not valid indefinitely. Equipment  changes or modifications affect the weight and balance data.  Too often pilots reduce the aircraft weight and balance into  a rule of thumb, such as: “If I have three passengers, I can  load only 100 gallons of fuel; four passengers, 70 gallons.”  Weight and balance computations should be part of every  preflight briefing. Never assume three passengers are always  Aircraft, such as balloons and weight-shift control, do not  require weight and balance computations because the load  is suspended below the lifting mechanism. The CG range  in these types of aircraft is such that it is difficult to exceed  loading limits. For example, the rear seat position and fuel  of a weight-shift control aircraft are as close as possible to  the hang point with the aircraft in a suspended attitude. Thus,  load variations have little effect on the CG. This also holds  true for the balloon basket or gondola. While it is difficult  to exceed CG limits in these aircraft, pilots should never  overload an aircraft because overloading causes structural  damage and failures. Weight and balance computations are  not required, but pilots should calculate weight and remain  within the manufacturer’s established limit.  Aircraft are certificated for weight and balance for two  principal reasons:  1. The effect of the weight on the aircraft’s primary  structure and its performance characteristics  2. The effect of the location of this weight on flight  characteristics, particularly in stall and spin recovery  and stability  Figure 5-61.  Another formula that can be used for radius.  5-40  Weight and Balance  Figure 5-60.  Radius at 240 knots.  240 knots  11.26 x tangent of bank angle  R =  240 2  11.26 x tangent of 30°  R =  V 2  R =  11.26 x 0.57735  57,600  R = 8,861 feet  (four times the radius at 120 knots)  The radius of a turn required by an aircraft traveling at 240 knots  using the same bank angle in Figure 4-51 is 8,861 feet. Speed  is a major factor in a turn.  r = speed (fps) x  360  ROT  Pi ( π )  2  202.8 x 68.6  π 2  r =  13,912  π 2  r =  4,428  2 r =  = 2,214 feet 