TD 30

Question 1

Complete Loss of Tail Rotor Thrust

Answer 1

This situation involves a break in the drive system, such as a severed driveshaft, causing the tail rotor to lose power.

Indications:
1. Pedal input has no effect on helicopter trim.
WARNING
Degree of roll and side-slip may be varied by varying throttle and/or collective. (At airspeed below approximately 50 knots, the side-slip may become uncontrollable, and the helicopter will begin to spin on the vertical axis.)
2. Nose of the helicopter turns to the right (left side slip).
3. Left roll of fuselage along the longitudinal axis.

Procedures:
1. If safe landing area is not immediately available, continue powered flight to suitable landing area at or above minimum rate of descent autorotational airspeed.
2. When landing area is reached, make an autorotational landing (Throttle Closed).
3. Use airspeed above minimum rate of descent of airspeed.
NOTE
Airflow around the vertical fin may permit controlled flight at low power levels and sufficient airspeed when a suitable landing is not avail either; however, the touchdown shall be accomplished with the throttle in the full closed position.
4. If run-on landing is possible, complete autorotation with touchdown airspeed as required for directional control.
5. If a run-on landing is not possible, start to decelerate from about 75 feet altitude, so that forward groundspeed is at a minimum when the helicopter reaches 10 to 20 feet; execute the touchdown with a rapid collective pull just prior to touchdown in a level attitude with minimum ground run.
6. Hover - Perform hovering autorotation.

Question 2

Loss of Tail Rotor Components

Answer 2

The severity of this situation is dependent upon the amount of weight lost. Any loss of this nature will result in a forward center of gravity shift, requiring a aft cyclic. A full autorotational descent and landing should be accomplished with a run-on type termination if to an improved surface, or minimum ground run if to an unimproved surface. Landing should be accomplished in a level attitude.

Indications:

1. Varying degrees of right yaw depending on power applied and airspeed at the time of failure.
2. Forward CG shift.

Procedures:

1. Enter authoritative descent (Throttle Closed)
2. Maintain airspeed above minimum rate of descent airspeed.
3. If run-on landing is possible, complete autorotation with touchdown airspeed as required for directional control.
4. If run-on landing is not possible, start to decelerate from about 75 feet altitude, so that forward ground speed is at a minimum when the helicopter reaches 10 to 20 feet; execute the touchdown with a rapid collective pull just prior to touchdown in a level attitude with minimum ground run.

Question 3

Transverse flow effect

Answer 3

Definition: Differences in lift, drag, and induced flow between the fore and aft portions of the rotor disk occurring from 10-20 knots. In forward flight, air passing through the forward portion of the rotor disk is more horizontal (increased AoA and more lift) and air passing through the rear portion of the rotor disk is more vertical (reduced AoA and less lift).
The greater the distance the air flows over the rotor disk, the longer the disk has to work on it and the greater the deflection.

Indications:
Vibrations - this causes unequal drag and results in vibration, noticeable during takeoff and during deceleration for landing.
Right rolling motion - gyroscopic precession causes the effects to be manifested 90 degrees in the direction of rotation.

Corrective Action:
Cyclic feathering - apply left cyclic until after 10-20 knots, then move cyclic back to center.

Question 4

Hypoxia

Answer 4

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