distance must be determined to the nearest one-hundredth of  an inch.  [Figure 2-63]  The next step is to multiply the distance times the net weight  of the repair. This results in an inch-pounds (in-lb) answer.  If the in-lb result of the calculations is within specified  tolerances, the control surface is considered balanced. If  it is not within specified limits, consult the manufacturer’s  service manuals for the needed weights, material to use for  weights, design for manufacture, and installation locations  for addition of the weights. The scale method of balancing a control surface requires the  use of a scale that is graduated in hundredths of a pound.  A support stand and balancing jigs for the surface are also  required.  Figure 2-64  illustrates a control surface mounted  for rebalancing purposes. Use of the scale method requires  the removal of the control surface from the aircraft. The balance beam method is used by the Cessna and Piper  Aircraft companies. This method requires that a specialized  tool be locally fabricated. The manufacturer’s maintenance  manual provides specific instructions and dimensions to  fabricate the tool. Once the control surface is placed on level supports, the  weight required to balance the surface is established by  moving the sliding weight on the beam. The maintenance  manual indicates where the balance point should be. If the  surface is found to be out of tolerance, the manual explains  where to place weight to bring it into tolerance. Aircraft manufacturers use different materials to balance  control surfaces, the most common being lead or steel.  Larger aircraft manufacturers may use depleted uranium  because it has a heavier mass than lead. This allows the  counterweights to be made smaller and still retain the same  weight. Specific safety precautions must be observed when  handling counterweights of depleted uranium because it is  radioactive. The manufacturer’s maintenance manual and  service instructions must be followed and all precautions  observed when handling the weights.  Aircraft rigging involves the adjustment and travel of movable  flight controls which are attached to aircraft major surfaces,  such as wings and vertical and horizontal stabilizers. Ailerons  are attached to the wings, elevators are attached to the  horizontal stabilizer, and the rudder is attached to the vertical  stabilizer. Rigging involves setting cable tension, adjusting  travel limits of flight controls, and setting travel stops.  In addition to the flight controls, rigging is also performed  on various components to include engine controls, flight  deck controls, and retractable landing gear component parts.  Rigging also includes the safetying of the attaching hardware  using various types of cotter pins, locknuts, or safety wire.  The Type Certificate Data Sheet (TCDS) is a formal  description of an aircraft, engine, or propeller. It is issued by  the Federal Aviation Administration (FAA) when the FAA  determines that the product meets the applicable requirements  for certification under 14 CFR. It lists the limitations and  information required for type certification, including airspeed  limits, weight limits, control surface movements, engine  make and model, minimum crew, fuel type, thrust limits,  rpm limits, etc., and the various components eligible for  installation on the product. Figure 2-63.  Calculation method measurement. Figure 2-64.  Balancing setup.  Aircraft Rigging Rigging Specifications Type Certificate Data Sheet Hinge center line Center of repair area Measurement in inches Chord line Rudder Adjustable support Trim tab Bubble protractor Hinge center line Mounting bracket Support stand Weight scale 2-39