Introduction to Control / Performance Flight

General BASIC INSTRUMENT FLYING-FIXED WING Aircraft attitude is the relationship of its longitudinal and lateral axes to the Earth's horizon. An aircraft is flown by controlling the attitude and power as necessary to produce the desired performance. This is known as the "control and performance concept" of attitude instrument flying and can be applied to any basic flight maneuver.

Power Conditions There are two basic situations that can exist when describing flight of airplanes which will change the methods of controlling the aircraft. For that reason, it becomes very important to understand the POWER CONDITION that you are operating in.

Power Conditions There are only TWO basic power conditions for flight. They are known as POWER CONDITION I, and POWER CONDITION 2.

Power Conditions Power Condition 1 Power Condition 1 (PC1) - power is available and variable. This means that, at the discretion of the pilot, power may be adjusted or changed. This can also be defined as when the flight path angle, altitude or rate of climb or descent of the aircraft is fixed or constant, and the power is variable.

Power Conditions Power Condition 1 Some examples of Power Condition 1 (PC1) are Level Flight (Fixed Altitude) Normal Approach visual approach to Landing (Fixed Flight Path - On VASI or aim-point) ILS approach (Fixed Flight Path - On Glide-slope) Normal Descents "Note: Normal descents are descents with power set to any position EXCEPT idle power.

Power Conditions Power Condition 2 Power Condition 2 (PC2) - power is fixed by choice or by accident. This means that if the pilot sets the power to a fixed position, such as MAX POWER, CLIMB POWER or IDLE POWER, or if the power is fixed by accident such as an engine failure, you are operating in PC2. This can also be defined as when the power is fixed and the flight path is variable.

Power Conditions Power Condition 2 Some examples of Power Condition 2 (PC2) are: Take-off (Fixed Power at Max Or Predetermined Limit) Power Off Situations (Fixed Power - by Accident) Idle Power Descents" (Fixed Power At Idle - by Choice) "Note: Power idle descents (by choice) are not very common when operating reciprocating engines. It is important to realize that this condition does exist and is more common in jet powered aircraft flying.

Power Conditions Power Condition 2 When operating in PC2: Pitch Controls Either Airspeed, Vertical Velocity OR Flight Path Angle. When operating in PC2, the only variable that can be manipulated is PITCH. It is also reasonable to assume that since we only have one variable (pitch) we can only have one controlled output. That is why pitch controls EITHER airspeed OR vertical velocity, but not BOTH SIMULTANEOUSLY.

Control Parameters Now that you understand the Power Conditions, you can examine the exact methods of accurate aircraft control. In order to do this, we must discuss the three control inputs that allow you to control the airplane. These are known as the CONTROL PARAMETERS. There are three Control Parameters that allow you to control altitude, heading and airspeed. They are: PITCH CONTROL BANK CONTROL POWER (THRUST) CONTROL "Note: Yaw or rudder is not considered a control parameter in - flight because its only purpose is to compensate adverse yaw either from aileron usage or from asymmetric thrust situations.

Specific Flight Characteristics In a light single engine airplane, an increase in thrust will increase tail down force, an cause a PITCH UP tendency.

Specific Flight Characteristics In a light single engine airplane, an decrease in thrust will decrease tail down force, an cause a PITCH DOWN tendency.

Specific Flight Characteristics Free Q (dynamic pressure) In a light MULTIENGINE TRAINER equipped with a “T - TAIL” an increase or decrease in thrust will have little effect on PITCH because the tail flies in free dynamic pressure.

Specific Flight Characteristics Free Q (dynamic pressure) Center of Gravity In a high performance BUSINESS JET, an increase or decrease in thrust will have A REVERSE EFFECT on PITCH because the CENTER OF THRUST is above the CENTER OF GRAVITY. That is an increase in thrust will cause a PITCH DOWN, and a decrease in thrust will cause a PITCH UP.

Specific Flight Characteristics SPECIFIC FLIGHT CHARACTERISTCS, ARE NOT METHODS OF CONTROL. IN power condition 1 FLY PITCH to FLIGHT PATH ANGLE, THRUST TO AIRSPEED, & TRIM THE CONTROL PRESSURE TO NEUTRAL.

After Takeoff - Power Condition 2 Pitch & Bank Control Pitch Performance Bank Performance Power Fixed by Choice

Straight & Level - Power Condition 1 Pitch & Bank Control Pitch Performance Power Performance Bank Performance Power Control

Level Turn - Power Condition 1 Pitch & Bank Control Pitch Performance Power Performance Bank Performance Power Control

Steep Turn - Power Condition 1 Bank Performance Pitch Performance Pitch & Bank Control Power Performance Power Control

Constant Rate Descent - Power Condition 1 Pitch & Bank Control Power Performance Bank Performance Pitch Performance Power Control

Thrust / Drag Curve L/D max - Jet L/D max - Prop

Thrust / Drag Curve Back Side - Region of Reverse Command - NOT Performance - YES Front Side

Thrust / Drag Curve COMMAND IS CONTROL IT IS DYNAMIC - A CHANGE IN SOMETHING Back Side - Region of Reverse Command - NOT Performance - YES PERFORMANCE IS STEADY STATE NOTHING IS CHANGING CONTROL - IT TAKES LESS THRUST TO TO DECELERATE Front Side PERFORMANCE - IT TAKES MORE THRUST TO MAINTAIN A SLOWER SPEED

Slow Flight - Power Condition 1 Pitch & Bank Control Pitch Performance Power Performance Bank Performance Power Control

Cockpit View - Landing Aim Point - Pitch Thrust - Aispeed Lower Rear Anatomical reference

END OF CONTROL PERFORMANCE INTRODUCTION