SYSTEMS 1 Primary Flight Controls

. What are the primary flight controls and which axis does each control?

Ailerons → Roll (longitudinal axis)

Elevator → Pitch (lateral axis)

Rudder → Yaw (vertical axis)

How are the primary flight controls actuated in a typical Cessna 172?

Mechanically, using control cables, pulleys, bell cranks, and pushrods connecting the cockpit controls to the control surfaces.

How do ailerons create roll?

They change the camber and lift on each wing:

Up aileron → less lift

Down aileron → more lift The difference in lift causes the airplane to roll.

What is adverse yaw and what causes it?

Adverse yaw is the tendency of the airplane to yaw opposite the direction of roll due to increased drag on the wing with the down aileron.

5. How is adverse yaw corrected?

By applying rudder in the direction of the turn to coordinate the maneuver.

What happens aerodynamically when the elevator is deflected upward?

The tail produces more downward force, causing the nose to pitch up.

7. Why do flight controls become less effective at low airspeed?

Because there is less airflow over the control surfaces, reducing aerodynamic force.

8. What is control harmony?

Control harmony refers to how balanced and proportional the response of the ailerons, elevator, and rudder feel to the pilot.

9. How does propeller slipstream affect the rudder?

Slipstream increases airflow over the rudder, making it more effective, especially at low airspeed and high power.

10. Why is proper rigging of flight controls critical?

Improper rigging can cause control imbalance, increased drag, abnormal handling, or loss of control authority.

SCENARIOS

SCENARIOS

1. During preflight, the yoke moves freely but the ailerons don't respond normally. What do you do?What risk it poses and how to mitigate

Do not fly. This indicates a control disconnect or restriction. The aircraft is unairworthy. Loss of control risk and Ground aircraft and notify maintenance

2. You notice stiff elevator control during taxi. What risk does this present?

It could indicate binding, ice, or mechanical interference, risking inability to rotate or flare.

3. After takeoff, the aircraft rolls slightly left hands-off. What might cause this?

Rigging imbalance

Engine torque

Trim mis-set

4. How would you detect a primary flight control malfunction in flight?

Uncommanded movements

Heavy or sluggish controls

Abnormal control pressures

5. What is the risk of over-controlling at low airspeed?

It can lead to stalls, spins, or loss of control, especially close to the ground.

6. You lose rudder effectiveness during a crosswind landing. What skill becomes critical?

Proper aileron use, power management, and timely go-around decision.

7. What would you do if an aileron cable failed in flight?

Use rudder for directional control

Reduce airspeed

Land as soon as practical

8. Why is coordinated flight important from a risk standpoint?

Uncoordinated flight increases stall speed and spin risk.

9. How does improper trim usage increase workload and risk?

It causes constant control pressure, increasing fatigue and distraction.

10. What skill does a DPE expect when checking flight controls before takeoff?

"Free, correct, and full movement" with visual confirmation.

11. You feel heavy control pressure during climb. What should you do?

Apply proper trim to relieve pressure and maintain precise control.

2. What risk exists if flight controls are not checked after loading passengers?

Objects may jam controls, leading to loss of control after takeoff.

13. Why is rudder coordination especially important during stalls?

To prevent yaw and spin entry during asymmetric lift conditions.

14. How does monitoring control feel help detect system failures early?

Changes in feel often precede mechanical failure, allowing early corrective action.

15. What ACS skill is demonstrated by smooth, coordinated control inputs?

Proper operation of airplane systems, maintaining control and safety.