TM 1-1520-238-10 Change 10 9-13 9.9.5 Tail Rotor Fixed Pitch Malfunction. A fixed pitch failure may be evident by slow, intermittent, or no response to pedal input or no pedal movement. A left or right yaw may be apparent. a. In Ground Effect. If a failure occurs during in- ground-effect hover, reaction may vary from adjusting collective and PWR levers during a left rotation to acti- vating the CHOP collar to stop a right rotation. In any case, the primary concern should be to land the aircraft with as little yaw rate as possible. 1. If the aircraft has an uncontrolled turn to the left, a reduction in the PWR levers coordinated with an increase in collective may slow or stop the rotation so that a controlled power on de- scent to landing can be accomplished. 2. If the aircraft is not turning, a slight reduction in collective pitch will begin a descent. During the descent, a slight rotation to the left may be present; increasing collective just prior to touchdown should stop the rotation. 3. If the aircraft has an uncontrolled turn to the right, reduce collective to begin descent. At approximately 5 to 10 feet AGL perform a hov- ering autorotation by CHOP Collar – CHOP or PWR Levers – OFF. b. Out-Of-Ground Effect. 1. If little or no right rotation or if left rotation is ex- perienced and control can be maintained, the aircraft should be accelerated into forward flight and perform approach and landing ap- propriate to power setting and condition of flight at time of failure. 2. If the aircraft cannot be accelerated into for- ward flight, initiate a power-on descent. Col- lective should be adjusted so that an accept- able compromise between rate of turn and rate of descent is maintained. At approximate- ly 5 to 10 feet above touchdown, perform a hovering autorotation by CHOP Collar – CHOP or PWR Levers – OFF. 9.9.6 Main Transmission Input Drive Clutch Fail- ure. An input drive clutch malfunction is most likely to occur during engine start or when an engine power lever is advanced. Indications may include: erratic torque in- dication on the affected engine, or a complete loss of torque indication on the affected engine, and/or N_p of the affected engine exceeding N_r. If the failure is a sud- den disengagement, the torque of the opposite engine will double as it attempts to carry the load. A sudden high torque input drive clutch engagement may cause severe engine and/or drive train damage. A sudden en- gagement is indicated by a loud noise and/or a sudden increase in engine torque. Should an input drive clutch fail to engage, perform the following: CAUTION When clutch fails to disengage, dam- age to the affected engine will result (due to lack of oil pressure) if both engines are not shut down simulta- neously. When clutch fails to engage, do not shut down both engines simulta- neously. Damage may result if there is sudden engagement. a. In Flight. 1. PWR lever (affected engine) – IDLE. If N_p of the affected engine is below N_r (indicating the clutch is disengaged): 2. EMER ENG SHUTDOWN (affected engine). 3. LAND AS SOON AS PRACTICABLE. If N_p of the affected engine is not below N_r (indicating the clutch has failed to disengage): 4. LAND AS SOON AS POSSIBLE 5. EMER ENG SHUTDOWN (both engines simultaneously) b. On Ground (with indications that a clutch has failed to engage). 1. EMER ENG SHUTDOWN (affected engine only) 2. Check N_G is less than 10% (affected engine) 3. Perform normal engine shutdown.