✈️ K1a – Primary Flight Controls

Q: What are the primary flight controls and what do they control

A: Ailerons—roll, Elevator—pitch, Rudder—yaw.

Q: How are the ailerons controlled in a 172S?

A: By control wheel through cables, bellcranks, and pushrods.

Q: What is adverse yaw?

A: Yaw toward the rising wing due to increased drag on the down aileron side.

Q: How do you correct adverse yaw?

A: Apply coordinated rudder with aileron input.

Q: Why do control forces feel lighter at low speeds?

A: Less airflow over the control surfaces.

Q: What is differential aileron deflection?

A: Up aileron moves more than down to reduce adverse yaw.

Q: Describe the elevator system.

A: Control column via cable and bellcrank moves elevator; provides pitch control.

Q: What happens when you pull back on the yoke?

A: Elevator up → tail down → nose up.

Q: How does the rudder work?

A: Pedals move cables that deflect rudder for yaw control.

Q: What provides stability if rudder cables break?

A: Aerodynamic balance and trim hold limited directional control.

Q: Why check "free and correct" movement before taxi?

A: Confirms cables connected and movement correct direction.

Q: What causes flutter?

A: Excessive speed or loose components—can cause structural failure.

Q: What's the difference between servo and balance tabs?

A: Servo tabs move opposite main surface to reduce pilot effort; balance tabs move with it.

Q: What is the purpose of control surface rigging?

Ensures neutral trim and equal deflection both directions.

Q: What could happen if controls are rigged backward?

Reversed response—loss of control; abort flight.

Q: You move the yoke left and see the left aileron go down. What do you do?

A: Stop—controls reversed, maintenance required.

Q: Roll tendency to right after takeoff—what might cause that?

Aileron rigging issue or fuel imbalance.

Q: Elevator feels stiff—what could it mean?

Cable binding or foreign object in linkage.

Q: DPE: "You lose elevator control. How can you still pitch?"

Use trim and power to control attitude; plan emergency landing.

Q: Rudder pedals loose during taxi—safe to fly?

No, control connection may be failed.

Q: Airplane rolls left when you apply right aileron—why?

Asymmetric lift or jammed hinge; return for inspection.

Q: DPE: "Why reduce speed in turbulence?"

To prevent control-surface overloading and flutter.

Q: Elevator "clunk" on preflight—what could cause it?

Loose bearing or hinge; maintenance needed.

Q: DPE: "How can you confirm proper rigging after maintenance?"

Full-deflection control check; verify correct surface movement visually.

Q: You experience strong roll when applying flaps—cause?

Asymmetrical lift or partial flap extension affecting roll coupling.

Q: Elevator effectiveness decreases at low speed—why?

Less airflow over tailplane reduces control authority.

Q: DPE: "Describe secondary effect of rudder."

Yaw → roll (dihedral effect).

Q: If gust causes elevator buffet, what's happening?

Tailplane stall or control surface vibration—lower AoA.

Q: DPE: "Why must you hold controls fully into the wind while taxiing?"

Prevent control-surface lift and ground damage.

Q: Yoke moves freely but ailerons don't—what's your action?

Abort flight; disconnected control cable.

Q: Control stiffness increases with airspeed—why?

Higher dynamic pressure increases control loads.

Q: DPE: "Why is control feedback important?"

It provides tactile stall cues and stability information.

Q: How do you identify a control restriction in flight?

Limited response range or asymmetric force.

Q: DPE: "Describe how to maintain pitch if trim jams nose-up."

Use forward pressure and power changes to manage descent; land ASAP.

Q: After turbulence, you notice a rattle in control surfaces—what could that be?

Loose hinge or counterweight; possible flutter risk.

Q: Why do some aircraft use pushrods instead of cables?

Reduces stretch, increases control precision.

Q: What's the effect of a partially jammed aileron?

Reduced roll authority; possible control reversal.

Q: Why check for gust locks removed before start?

Prevents surface damage or jammed controls.

Q: What aerodynamic phenomenon occurs if elevator balance weights loosen?

Flutter at high speed—extremely dangerous.

Q: How could you detect control-cable tension issue in flight?

Slack feel and delayed surface response.

Q: What happens if trim tab linkage fails in cruise?

Trim tab may trail free—unexpected pitch change.

Q: DPE: "Explain dynamic balance of control surfaces."

: Balancing weight ahead of hinge line to reduce flutter.

Q: Why does control feel heavier with increased G-load?

Increased downwash and aerodynamic resistance.

Q: How does slipstream affect control feel in climb?

Propwash over surfaces increases rudder and elevator authority.

Q: What is the risk of frozen controls in flight?

Loss of movement; use cockpit heat or descend to warmer air.

Q: DPE: "Describe how primary controls interact in a coordinated turn."

Ailerons bank, rudder counters yaw, elevator maintains load factor.

Q: How could improper rigging affect stall characteristics?

One wing stalls first; roll-off asymmetrically.

Q: Why are control stops important?

Prevents over-travel and linkage damage.

Q: DPE: "Explain the relationship between control deflection and stability."

Larger deflection reduces stability; small, precise inputs maintain control.

Q: After maintenance, why check hinge bolts with safety wire?

Prevents hinge bolt backing out causing loss of surface.