UNCONTROLLED COPY WHEN DOWNLOADED  Check with FSIMS to verify current version before using  2-3  confronted by a multitude of grapples and hitch releases, each line and release should be  positively matched to prevent confusion in the event of an emergency. The length of flights and  fuel consumption should be considered in determining how many hooks will be added to a  multiple tow hitch. See Figure 2-4, Examples of a Multiple Grapple Hook Installation.  BOOM-HOOK SYSTEM.  An alternative to the multiple tow hitch system is a boom pickup  system. A typical installation consists of a rigid boom pivoted aft of the landing gear,  approximately the length of the aft fuselage. The boom is equipped with a hook that can be used  to snag the towline and pick up the banner. A retract cable is employed to stow the boom under  the fuselage during takeoff and landing.  The boom system eliminates the multiple grapple line of the multiple hitch system as well as the  problems previously discussed concerning grapple line snarling and grapple bounce. On the  negative side, due to the relatively short length of the boom, the airplane must be flown more  carefully during the banner pickup and high enough to avoid snagging the towline with the  landing gear, yet low enough to engage the bridle with the hook. Turbulence can cause the hook  to bounce while in the normal trail position, and it may swing from side to side in a crosswind. 