Lesson Overview

The student should develop knowledge of the elements related to straight and turning descents and have the ability to maintain a constant airspeed descent in both situations.

References : Airplane Flying Handbook (FAA-H-8083-3C, page(s) 3-22)

Key Elements

  1. Decreased Drag

  2. Coordination

  3. Crosschecking
Elements

  1. Flight Controls

  2. Forces of Flight

  3. Types of Descents

  4. Integrated Flight Instruction

  5. Straight Descents

  6. Turning Descents

  7. Trim Procedure

  8. Overcoming Tenseness and Over-Controlling
Schedule

  1. Discuss Objectives

  2. Review material

  3. Development

  4. Conclusion
Equipment

  1. White board and markers

  2. References
IP Actions

  1. Discuss lesson objectives

  2. Present Lecture

  3. Ask and Answer Questions

  4. Assign homework
SP Actions

  1. Participate in discussion

  2. Take notes

  3. Ask and respond to questions
Completion Standards

The student understands the factors related to descents and can properly perform a descent while in straight or turning flight.

Instructor Notes

Attention

Straight and turning descents are the final chapter of the fundamentals of flying. This along, with the other fundamentals, is what everything else in flying builds upon. Getting these maneuvers right will improve all future maneuvers.
Overview

Review Objectives and Elements/Key ideas
What

A descent is made when the aircraft is put in a configuration which will result in a loss of altitude.
Why

Descents are a fundamental part of flight, understanding and being properly performing a descent will result in everything else being considerably easier.

Lesson Details

The first thing to understand are the controls which are involved in straight descents and descending turns. As is the case with virtually all basic maneuvers all of the primary flight controls are involved, and there is rotation around the three axis (pitch, roll, and yaw).

Pitch is controlled by the elevators, and forward and back pressure on the elevator control is what causes pitch changes. Back pressure deflects the trailing edge of the elevator up decreasing the camber of the horizontal control surface thus creating a downward force. Forward pressure does exactly the opposite.

Roll is controlled by the ailerons, and right/left pressure on the aileron control is what causes roll changes. When the right aileron deflects up the decreasing camber results in decreased lift on the right wing, and the left aileron deflecting down increases the camber resulting in increased lift. This causes a roll to the right. Moving the aileron control to the left does exactly the opposite.

Yaw is controlled by the rudder. When the rudder is deflected into the airflow a horizontal force is exerted in the opposite direction.

Types of Descents

Partial Power Descent

This is the normal method of losing altitude, with a common target descent rate being approximately 500 feet per minute. The aircraft manufacturer should have a recommended descent airspeed and configuration for the descent. The desired airspeed, pitch attitude, and power combination should be preselected and kept constant.

Descent at Minimum Safe Airspeed

This is a nose-high power assisted descent primarily used for clearing obstacles during a short field approach. This creates a steeper than normal descent angle and excessive power may be needed to accelerate from the low airspeed should an excessive descent develop.

Glide

This is a basic maneuver in which the airplane loses altitude in a controlled descent with little or no power. The descent rate is controlled by balancing the forces of gravity and lift. When operating in this mode for an extended period of time it is recommended that the pilot "clear" the engine periodically.

Straight Descents

Entry

  1. Reduce power to the desired setting (potentially idle) and maintain a constant altitude with back elevator pressure until the desired airspeed is reached

  2. Once the target airspeed is reached allow the nose to drop to maintain the desired airspeed

Maintaining the Descent

  1. Once stabilized crosscheck airspeed indicator to ensure the desired speed is being maintained (integrated flight instruction)

    1. If the airspeed is high, slightly raise the nose and allow the airspeed to stabilize to confirm the adjustment

    2. If the airspeed is low, slightly lower the nose and allow the airspeed to stabilize to confirm the adjustment

  2. Once at the desired airspeed note the nose in relation to the horizon and the position of the attitude indicator

  3. Trim the airplane to relieve the control pressures

  4. Maintain coordination with the rudder

Return to Straight and Level Flight

  1. Initiate the level off at approximately 10% of the rate of climb

    1. Example: If the aircraft is descending at 500 fpm the level off would start approximately 50 feet above the desired altitude

  2. The nose should be raised and power increased to the desired cruise setting

    1. Adding power and increasing speed will tend to raise the nose

  3. The aircraft should be re-trimmed for level flight

Turning Descents

Entry

  1. Establish a descending turn in one of two ways

    1. Establish a straight descent and then turn

    2. Enter the turn and descent simultaneously

Maintaining the Descending Turn

  1. Maintain a constant bank angle and pitch attitude

  2. Combine the level turns and straight descent references

    1. Pitch is maintained in relation to the horizon, and adjustments are made with the elevator and a cross check of the visual indications with the instruments

    2. Bank is maintained in relation to the angle of the cowling and the horizon, and adjustments are made with the ailerons and a cross check of the visual indications with the attitude indicator and turn coordinator

    3. As pitch and/or bank are corrected, the other may need correction as well

  3. Once at the desired airspeed, note the nose in relation to the horizon and the position on the attitude indicator

  4. Trim as needed, potentially quite often

  5. Maintain coordination with the rudder

Trim Procedure

  1. First set the power, the pitch, and let the airspeed stabilize

  2. Establish and hold the airplane in the desired attitude using the primary flight controls

    1. The proper attitude should be established with reference to the horizon and then verified by reference to the flight instruments

  3. Then apply trim to relieve whatever pressure was required

    1. The attitude must be established and held first, then control pressures trimmed out so that the airplane will maintain the desired flight attitude in "hands off" flight. As previously discussed, if power changes the pitch attitude to maintain level flight will change, and the aircraft will have to be re-trimmed.

  4. Use the trim frequently, and in small amounts, but don’t attempt to "fly the plane" by use of just the trim.

Any control pressures felt should be the result of deliberate pilot control input during a planned change in airplane attitude. It should not be the result of pressure being applied by the aircraft because the pilot allowed the aircraft to assume control.

Overcoming Tenseness and Over-Controlling

When a pilot becomes tense it becomes easy to start to over-control the aircraft. This is evidenced by the pilot engaging in control movements rather than exerting control pressures. The movements can become jerky and large movements of the flight controls. It also might be evidenced by the presence of white knuckles or general overall nervousness.

This can be prevented by overtly acknowledging the over-controlling tendency, and reverting to a light finger-tip grip of the control, and a reminder of the control pressures desired. If over-controlling is constant one technique is to place a wooden pencil on top of the middle and ring finger and under the index and pointer finger of the hand the student uses to fly. If the student starts the death grip, the force of the pencil on the middle/ring finger will be a reminder to relax, if the student continues to tighten their grip the pencil will break.

Common Errors

  • Failure to cross-check and correctly interpret outside and instrument references

  • Application of control movements rather than pressures

  • Uncoordinated use of the flight controls

  • Faulty trim procedure

  • Failure to clear engine and use carburetor heat, as appropriate

Conclusion

Descents are part of the foundation of flying and as simple as they sound, they are extremely important. As in all of the fundamentals of flight it is important to learn to fly the airplane by visual references and back those references up with the instrument indications.

ACS Requirements

To determine that the applicant:

  1. Exhibits instructional knowledge of the elements of straight descents and descending turns by describing:

    1. Effect and use of flight controls.

    2. The Integrated Flight Instruction method.

    3. Outside and instrument references used for pitch, bank, yaw, and power control; the crosscheck and interpretation of those references; and the control procedure used.

    4. Trim procedure.

    5. Methods that can be used to overcome tenseness and over controlling.

  2. Exhibits instructional knowledge of common errors related to straight descents and descending turns by describing:

    1. Failure to cross-check and correctly interpret outside and instrument references.

    2. Application of control movements rather than pressures.

    3. Uncoordinated use of flight controls.

    4. Faulty trim procedure.

    5. Failure to clear engine and use carburetor heat, as appropriate.

  3. Demonstrates and simultaneously explains straight descents and descending turns from an instructional standpoint.

  4. Analyzes and corrects simulated common errors related to straight descents and descending turns.