Exercise 23: Limited power operations

OBJECTIVES:

 

In this lesson, the student will learn how to safely fly the helicopter when the power is limited by altitude, temperature, weight or possible malfunction. The student will also understand the power requirements for operating in confined areas where power may be limited as a result of obstruction in the approach or take off path.

 

LESSON CONTENT:

 

  1. Revise the Limit manifold pressure chart and how to calculate the amount of surplus power available.
  2. Brief the student on the type of approach that can be flown with the amount of reserve power available
    • Running – 1” MAP Surplus
    • Cushion – 1-2” MAP Surplus
    • Normal/Steep – 2-3” MAP Surplus
    • Vertical – +3” MAP Surplus
  3. Revise the power required/Power available graph
  4. Recap the effect of wind on the ground distance covered before transitional lift is reached.
  5. Demonstrate the Running Take Off:
    • Fully brief the student on running take offs
    • Ensure that this exercise is performed over a safe surface, free of any obstruction that could snag or impede the skids as the aircraft slides along the ground
    • Note the power required to hover IGE when repositioning for the take off, and assign a power limit for the simulated running take off by limiting the student to 1” surplus power available.
    • Align the helicopter into wind, towards a suitable reference point.
    • Raise the collective until the helicopter becomes light on the skids, hold this state and allow the ground cushion to build.
    • Apply gentle forward cyclic to begin sliding forward to gently skim the surface. The pedals may need to be twitched slightly to encourage the initial slide.
    • Ensure that the student does not fixate on the ground when doing so and continues to fly eyes up, towards the selected reference point.
    • Keep the nose straight in direction of travel aligned with the reference point, do not allow sideways movement or drift.
    • Encourage the student to be patient in allowing the ground cushion to build and to allow for growing positive airspeed in order to lift the helicopter off the ground. Any impatience, and rushing to accrete forward speed will result in an aggressive nose attitude that cannot be maintained by the amount of power available and will result in the helicopter resettling on the ground.
    • Point out the tendency for one skid to lift first. At this point it’s important to reaffirm positive directional control with the pedals, and position control with the cyclic to ensure that a rolling moment is not induced.
    • Once Airborne, encourage the student to remain as close to the ground as possible, using the benefits of the ground cushion. Raising the collective slightly to prevent sinking.
    • At the translational lift point, use the additional power to increase speed and allow a very shallow climb.
    • Continue to accelerate through 40KIAS, staying close to the ground (Between 5-10ft)
    • At 53KIAS (RH22 Best ROC) rotate, raising the collective to maximum permitted power & climb away.
    • Anticipate a reduce ROC and shallow climb path; ensure 53KIAS is maintained for the Best ROC until all obstacles are cleared in the climb path.
  6. Demonstrate the Running Landing:
    • Fully brief the student on Running landings
    • Ensure that this exercise is performed over a safe surface, free of any obstruction that could snag or impede the skids as the aircraft slides along the ground. Ensure that the approach path is free of obstruction and can accommodate a shallow approach.
    • Set up a long shallow approach for the selected LZ to eliminate large power changes
    • Highlight the significance of operating into wind and its influence on run on speed and ground distance covered.
    • Select a reference point ahead to ensure that directional control is maintained
    • Gradually reduce speed and height, keeping speed above translational lift speed until a safe run on area can be assured
    • As translational lift is lost, raise collective slightly to prevent sudden sink.
    • Continue to decrease speed as much as possible before sliding the aircraft onto the selected area.
    • Anticipate that one skid may touch down first, and positive directional control must be maintained with the pedals, and positional control with the cyclic.
    • Encourage the student to keep looking up towards the reference point, and to not fixate on the ground.
    • Gently lower the collective to settle and slow the aircraft down by increasing ground friction.
    • Ensure that the student does not try to slow the aircraft down by applying aft Cyclic once in contact with the ground. Cyclic must remain neutral.
  7. Demonstrate the Cushion Take Off:
    • Fully brief the student on Cushion take offs
    • Ensure that this exercise is performed over a safe surface, free of any obstruction that could snag or impede the skids as the aircraft hovers close to the ground. Ensure that the take off path is free of obstruction and can accommodate a shallow take off path.
    • Note the power required to hover IGE, and assign a power limit for the simulated running take off by limiting the student to 2” surplus power available.
    • Ensure that this exercise is performed over a safe surface, free of any obstruction that could snag or impede the skids as the aircraft slides along the ground
    • Align the helicopter into wind, towards a suitable reference point.
    • Raise the collective until the helicopter is in a low hover (2FT Skid Height) hold this state and allow the ground cushion to build.
    • Apply gentle forward cyclic to initiate gentle forward movement
    • Ensure that the student does not fixate on the ground when doing so and continues to fly eyes up, towards the selected reference point.
    • Keep the nose straight in direction of travel aligned with the reference point, do not allow sideways movement or drift. Ensure positive directional control with the pedals and positional control with the cyclic.
    • Encourage the student to be patient in allowing the ground cushion to build and to allow for growing positive airspeed.
    • Encourage the student to try and assess when to anticipate reaching the translational lift point
    • At the translational lift point, use the additional power to increase speed and allow a very shallow climb.
    • Continue to accelerate through 40KIAS, staying close to the ground (Between 5-10ft)
    • At 53KIAS (RH22 Best ROC) rotate, raising the collective to maximum permitted power & climb away.
    • Anticipate a reduce ROC and shallow climb path; ensure 53KIAS is maintained for the Best ROC until all obstacles are cleared in the climb path.
  8. Demonstrate the Cushion landing:
    • Fully brief the student on cushion landings
    • Ensure that this exercise is performed over a safe surface, free of any obstruction that could snag or impede the skids as the aircraft slides along the ground. Ensure that the approach path is free of obstruction and can accommodate a shallow approach.
    • Set up a long shallow approach for the selected LZ to eliminate large power changes
    • Highlight the significance of operating into wind and its influence on run on the ground distance covered.
    • Select a reference point ahead to ensure that directional control is maintained
    • Gradually reduce speed and height, keeping speed above translational lift speed until a safe landing area can be assured
    • The key to this exercise is timing the point at which translational lift can be acceptably lost to ensure a zero hover touch down at zero forward speed.
    • As translational lift is lost, raise collective slightly to prevent sudden sink.
    • Continue to decrease speed and height allowing the ground cushion to build.
    • Anticipate that one skid may touch down first, and positive directional control must be maintained with the pedals, and positional control with the cyclic.
    • Encourage the student to keep looking up towards the reference point, and to not fixate on the ground.
    • Aim to touch down at zero forward speed with no hover.
    • Lower collective fully on touch down.

 

  1. Demonstrate the Steep take off:
    • Recap Over pitching, Over Boosting and Bunting
    • Recap Vortex ring State
    • Recap Low RPM recovery
    • Discuss power limiting factors particular to selected LZ
    • Recap the power available vs. power-required graph. Ensure that the student understands the speed at which best ROC can be achieved/Maximum reserve power available (53KIAS) and its significance to the exercise
    • Fully brief the student on normal or steep take offs.
    • Explain the relationship between groundspeed and angle of climb, and power and ROC.
    • Explain how any speed either side of 53KIAS will result in a reduced ROC.
    • Explain how a slower ground speed increases the angle of climb and a faster ground speed reduces the angle of climb
    • Point out how the obstruction/obstacle height determines the angle of climb speed.
    • Position the aircraft for take off, as far back within the confined of the landing area as possible, ensuring tail is clear of obstruction.
    • Select a reference point into wind, highlighting the positive effects of wind and how its effect will only be apparent once clear of the obstacle or obstruction
    • Establish a low hover, approximately 2FT AGL; allow the positive build up of the ground cushion.
    • Point out to the student the amount of power being used to maintain the hover, and how the power is reduced as the ground cushion becomes more effective
    • Conduct hover checks, Note surplus power available.
    • Direct the students eye to the obstacle that needs to be cleared in the take off path as well as the end of the appearance of rotor downwash, where TL can be expected to be reached
    • Select a DP (Decision Point) half way between the two points
    • Reaffirm DP Checks. (Positive ROC, RPM In the Green, Check power to ensure within prescribed limits and that the obstacle will be cleared)
    • If any of the above criteria are not met, positively affirm a decision not to continue with the take off and to initiate a decent to land.
    • Ensure the careful control of ROD when aborting the take off, reminding the student of the conditions likely to lead to the onset of Vortex ring state.
    • If DP Criteria are met, continue the climb out at selected take off angle until clear of the obstacle, after which standard climb out configuration can be set (60/65KIAS, ROC 500FPM)

 

  1. Demonstrate the Steep Approach:
    • Recap Over pitching and Over Boosting
    • Recap Vortex ring State
    • Recap Low RPM recovery
    • Discuss power limiting factors particular to selected LZ
    • Recap the OGE Hover graph, and ensure that an OGE hover can be maintained at the given altitude, weight and temperature.
    • Set up an approach towards the selected LZ, aim to overfly 50ft above the highest obstacle within the final approach track
    • Assist the student in assessing the required approach speed and angle to avoid an overshoot; select a DP just passed the highest obstacle, before the LZ.
    • If possible, maintain level flight and speed slightly above that for Translational Lift until clear of the obstacle.
    • Once clear of the Obstacle, reduce speed to that of a hover taxi and conduct DP Checks (Power sufficient, Engine Ts & Ps, Approach Angle manageable, LZ conditions)
    • If any of the above criteria are not met, positively affirm a decision made by the student to not continue with the landing
    • Demonstrate the go around procedure by applying forward cyclic to regain forward speed, resetting climbing power to climb away and reestablish an approach at a more suitable/safer LZ.
    • If the DP criteria are met, commit to the approach and initiate a decent
    • Select a reference point ahead, ensuring the use of the maximum space available within the LZ to not unnecessarily cramp the approach if the space is available, to ensure tail rotor clearance and MR disc clearance from all obstruction.
    • Maintain strong directional control with the pedals, aligned with the selected reference point, position and approach angle attitude with the cyclic.
    • Ensure that the student does not rush the descent and that he/she constantly manages the ROD, Keeping it below 200ft/min at all times.
    • Once established in an IGE hover within the LZ area, maneuver the helicopter into the best position for landing.

 

  1. Demonstrate the Vertical Take off:
    • Recap Over pitching, Over Boosting and Bunting
    • Recap Vortex ring State
    • Recap Low RPM recovery
    • Discuss power limiting factors particular to selected LZ
    • Recap the OGE Hover graph, and ensure that an OGE hover can be maintained at the given altitude, weight and temperature.
    • Select a reference point into wind, highlighting the positive effects of wind and how its effect will only be apparent once clear of the obstacle or obstruction
    • Raise the collective until the helicopter is in a low hover (1FT Skid Height) hold this state and allow the ground cushion to build to maximize its effects.
    • Point out to the student the amount of power being used to maintain the hover, and how the power is reduced as the ground cushion becomes more effective
    • Conduct hover checks, Note surplus power available.
    • Direct the students eye to the obstacle that needs to be cleared in the take off path
    • Select a DP (Decision Point) half way up the obstacle, and select a reference point for this
    • Raise the collective gently and smoothly to full available power for the climb and hold the attitude
    • Emphasize the importance of keeping the nose straight by use of the pedals, aligned with the into wind reference point and cyclic to prevent drift.
    • Reaffirm DP Checks. (Positive ROC, RPM In the Green, Check power to ensure within prescribed limits and that the obstacle will be cleared)
    • If any of the above criteria are not met, positively affirm a decision not to continue with the take off and to initiate a decent to land.
    • If DP Criteria are met, continue the climb out at selected take off angle until clear of the obstacle, after which standard climb out configuration can be set (60/65KIAS, ROC 500FPM)

 

  1. Demonstrate the Vertical Approach for landing:
    • Recap Over pitching and Over Boosting
    • Recap Vortex ring State
    • Recap Low RPM recovery
    • Discuss power limiting factors particular to selected LZ
    • Recap the OGE Hover graph, and ensure that an OGE hover can be maintained at the given altitude, weight and temperature.
    • Set up an approach towards the selected LZ, aim to overfly 50ft above the highest obstacle within the final approach track
    • If possible, maintain level flight and speed slightly above that for Translational Lift until clear of the obstacle.
    • Once clear of the Obstacle, reduce speed to that of a hover and conduct DP Checks (Power sufficient, Engine Ts & Ps, Approach Angle manageable, LZ conditions)
    • If any of the above criteria are not met, positively affirm a decision made by the student to not continue with the landing
    • Demonstrate the go around procedure by applying forward cyclic to regain forward speed, resetting climbing power to climb away and reestablish an approach at a more suitable/safer LZ.
    • If the DP criteria are met, commit to the approach and initiate a decent
    • Select a reference point ahead
    • Maintain strong directional control with the pedals, aligned with the selected reference point, position and approach angle attitude with the cyclic.
    • Ensure that the student does not rush the descent and that he/she constantly manages the ROD, Keeping it below 200ft/min at all times.
    • Once established in an IGE hover within the LZ area, maneuver the helicopter into the best position for landing.

 

COMPLETION STANDARDS:

 

At the completion of this exercise the student will be able to correctly assess the amount of power available from the helicopter based on a prescribed set of conditions. The student will understand the environmental factors, and aircraft configurations that further reduce the amount of power available, as will they understand the factors improving the amount of power available. This is exercise will expand on, and mature their decision making process, reinforcing good airmanship in the form of checks, and conscious awareness of prescribed limitations as well as how to manipulate a given situation to their favor. Their aircraft handling skills, and understanding of energy management will be further advanced. Throughout this exercise, the student will also display a good sense of situational awareness, and be able to correctly and confidently judge the available space to ensure constant tail and disc clearance from obstruction.

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