TM 1-1520-238-23 Change 10 1-407 1.138. OVERHAUL AND RETIREMENT SCHEDULE – continued Part Name Retirement Interval Notes Retirement Interval Hours Overhaul Interval Notes Overhaul Interval Hours Part Number Tail Rotor Strap Assembly 7-211421035-5 18,000 7-211421035-7 18,000 Tail Rotor Blade Assembly 7-311422050-3 4,600 7-311422050-5 4,600 7-311422050-7 4,600 7-311422050-9 4,600 Main Transmission Assembly 7-311310001-5 1,000 4,500 7-311310001-9 4,500 7-311310001-13 1,000 4,500 7-311310001-17 4,500 7-311310001-21 1,000 4,500 7-311310001-23 4,500 7-311310001-25 1,000 4,500 7-311310001-27 4,500 7-311210001-29 1,000 4,500 7-311310001-31 1,000 4,500 7-311310001-33 4,500 7-311310001-35 4,500 7-311310001-37 4,500 7-311310001-39 4,500 7-311310001-41 4,500 7-311310001-43 4,500 * Clutch Assembly 7-311310003 500 4,500 7-311310003-3 500 4,500 7-311310003-7 500 4,500 7-311310003-9 2,500 4,500 * Clutch, Sprag Drive 7-113100109 750 Main Rotor Drive Shaft 7-211350021 5,400 1 7-211350021-3 5,400 1 Main Rotor Drive Plate 7-211310098-5 5,400 7-211310098-7 5,400 7-211310098-9 5,400 7-211310098-11 5,400 GO TO NEXT PAGE