TM 55-1520-240-23-4 5-8 REMOVE ROTARY-WING HEAD    (Continued) 5-8 17.1.     Install lifting device (T30) (41) as follows: a. Position lifting device (T30) (41) on head (1). b. Turn three arms (43) inward under top flange (43.5) of head (1).  Make sure each arm points to the center of device (41) within  20  . Make sure each arm engages flange (43.5) at least  1/4 inch. c. Install three pins (42). CAUTION Do not use wrench to tighten nuts. Lifting device (T28) can be damaged. d. Hand tighten three nuts (44). 18. Attach two rope guide lines (45) around pitch housing (5).  Attach hoist (46) to lifting device (T30) (41). WARNING Head weighs  700 pounds  (1,750 pounds with blades attached) and can injure personnel if it drops.  Head must be supported by hoist and moved carefully to prevent injury. WARNING If rotor blades are installed, use special care to prevent blades from uncontrolled swinging.   Station personnel at tiedown lines of all blades.  Attempting to remove head without securing blades can result in injury to personnel and damage to helicopter. CAUTION Lift and lower head slowly and carefully to prevent damage to splines, thread, and surfaces. 19. Lift head (1).  Use hoist (46). 20. If rotor blades are not installed, position head (1) on handling adapter (T13) (47).  Have helper guide head. 21. Remove three pins (42).  Loosen three nuts (44) and turn three arms (43) outward. Remove lifting device (T30) (41). 5-51