Exercise 12 - Transitions

GROUND SCHOOL POINTS

Ground effect

Translational lift

Dissymmetry of lift and flap back

Tail rotor drift

Vortex ring

Flight Manual

  • Height Velocity Chart
  • Climb and descent power
  • Airspeed settings.

PREPARATION INSTRUCTION

Aim

For the student to learn how to:

    1. depart from the hover to the climb; and
    2. approach to the hover from forward flight.

Review

Straight and level flight, climbs and descents, hovering.

Motivation

Accurate transitions are extremely important, particularly in an operational environment.

Airmanship

  • Lookout
  • Wind Velocity
  • Checks

Teaching Points

    1. Transition to the climb

      Describe the transition from the hover to the climb as follows:

      1. establish a steady hover into wind;
      2. make a clearing turn and check area clear;
      3. complete pre-take off check;
      4. select an outside reference to assist directional control and ease cyclic forward slightly to initiate movement;
      5. At the same time, if required, increase power sufficiently to prevent sink;
      6. apply enough forward cyclic to overcome flapback;
      7. select climb attitude and power; and
      8. prevent yaw throughout and adjust cyclic as required to maintain climb attitude.
    2. Transition from forward flight to the hover (Standard Approach)
      1. Explain that the transition to the hover involves two separate requirements that have to be combined into one coordinated manoeuvre:
        1. Height Reduction:  Height must be reduced from approach altitude to the hover height above ground. Explain the straight-line or constant angle approach, describing the visual indications.
        2. Speed Reduction: Speed must be progressively reduced from the approach airspeed to a zero ground speed at the hover. Varying approach angles and/or wind conditions will cause the airspeed to vary a great deal from one approach to another. It is vital therefore, that the student learns to refer to ground speed only.
      2. Describe the procedure as follows:
        1. approach landing spot into wind at a specific altitude and airspeed;
        2. select a suitable approach angle (sight picture);
        3. initiate the approach by reducing power and commencing a progressive decrease in airspeed;
        4. maintain the approach angle with collective;
        5. establish apparent ground speed (a fast walking pace), and maintain it with cyclic;
        6. anticipate loss of translational lift;
        7. establish hover over the selected spot; and
        8. prevent yaw or sideways drift.
      3. Describe overshoot procedures as appropriate to type and local conditions.
      4. Introduction to hovering:

        If transitions are employed for introducing hovering, approaches should initially be made at a constant speed and constant angle, followed by a low overshoot. Speeds should be progressively reduced in subsequent approaches, first to a fast hover taxi, then to the point of losing translational lift, and finally to the hover itself. Sideways or rearward flight should be avoided. Ensure that the student regains forward flight before losing control of the hover.

    3. Explain that wind velocity will significantly affect helicopter performance and handling characteristics, as appropriate to type.

Confirmation

PRE-FLIGHT BRIEFING

AIR LESSON
    1. Demonstrate flapback and a transition from the hover to the climb.
    2. Student practice
    3. Demonstrate a transition to the hover, showing the visual cues resulting from failure to maintain a constant approach angle.
    4. Demonstrate a transition to the hover, showing the visual cues of a constant approach angle and the correct rate of closure.
    5. Student practice.
    6. Demonstrate overshoot procedures.
    7. Student practice

POST-FLIGHT DEBRIEFING

TIPS FOR INSTRUCTORS
    1. The concept of making an approach at a constant angle and at a progressively decreasing ground speed, is a difficult one for the student pilot to grasp. The use of diagrams in pre-flight briefing is essential.
    2. The instructor should be prepared for the fact that in the early stages, the student will almost certainly fail to anticipate the amount of power required when translational lift is lost coming to the hover. This can easily lead to either overpitching, over-revving, over-boosting/torquing or even incipient power settling.
    3. Another problem resulting from #2 is underestimating pedal requirements. Explain the greater the power required to establish the hover, the greater the pedal movement required to keep the aircraft straight, and this can only be corrected by using an outside reference.
    4. Emphasize assessing the approach in relation to ground speed and sight picture. This can only be accomplished by looking outside the helicopter with an occasional cross check of the instruments.
    5. Ensure the helicopter is moving straight with the direction of travel by use of pedals when close to the ground.
    6. Students should be encouraged to overshoot if the rate of descent is high and the airspeed is low.
    7. This exercise may be used as a means of teaching the hover. (See Exercise 10).
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