A single main rotor helicopter experiences a complete loss of tail rotor thrust (not a control system failure) while in cruise flight at 80 knots. According to recommended emergency procedures, the pilot should:
- Aincrease collective pitch and attempt to climb to gain altitude before deciding on a course of action
- Bapply full opposite pedal to stop the yaw before taking any other action
- Cmaintain airspeed, gradually reduce power, and plan a controlled, shallow approach to a running landing, using the vertical fin for directional control
- Dimmediately close the throttle and enter a full autorotation regardless of altitude
Show answer & explanationAnswer & explanation
Correct answer: C. maintain airspeed, gradually reduce power, and plan a controlled, shallow approach to a running landing, using the vertical fin for directional control
With a complete loss of tail rotor thrust at cruise airspeed, forward airspeed and the vertical fin provide some weathervaning directional control; the recommended technique is to maintain speed, gradually reduce power, and execute a controlled shallow approach to a running (or roll-on) landing rather than an abrupt power change that could aggravate the uncontrolled yaw.
Why the other options are wrong
- A. Increasing collective increases torque and worsens the uncontrolled yaw since there is no tail rotor thrust to counter it.
- B. With complete loss of tail rotor thrust, there is no tail rotor to respond to pedal input; pedal alone cannot stop the yaw.
- D. An abrupt throttle closure at cruise airspeed can cause an uncontrolled yaw due to sudden torque change and is not recommended when thrust is completely lost.
Complete Tail Rotor Thrust Loss (Cruise Flight)
When a helicopter loses all tail rotor thrust in cruise flight, forward airspeed and the vertical fin provide partial anti-torque effect; the pilot should maintain airspeed, gradually reduce power, and execute a controlled running landing.
- Different emergency techniques apply depending on flight regime (hover vs. cruise)
- At cruise speed, the vertical fin and airspeed help counteract torque-induced yaw
- Abrupt power changes can worsen uncontrolled yaw
- Goal is a controlled running/roll-on landing rather than abrupt autorotation entry
Memory trick: Keep your speed, ease the power, let the fin fly you home.