Flapless vs Flap Approach Techniques

In this section, we will explore the key differences between a flapless approach and an approach with flaps. We will specifically address how these configurations affect aircraft attitude during descent, approach path angle, threshold and touchdown speeds, and landing roll. This understanding is critical for pilots preparing for the CASA RPL pilot license theory exam.

Attitude During Descent

Flapless Approach

• Higher Pitch Attitude: During a flapless approach, the aircraft must maintain a higher nose attitude to achieve a similar angle of attack due to the absence of the increased lift usually provided by flaps. This results in a shallower approach angle and potentially higher airspeeds The One Aerodynamics Subject That Drives Me Nuts - thecfiguy.com.

Approach with Flaps

• Lower Pitch Attitude: Deploying flaps increases drag and more lift, allowing a lower nose attitude. This configuration facilitates a steeper descent angle without increasing airspeed. Initial flap deployment may cause temporary ballooning, but the effect stabilizes, enabling a more controlled and steeper descent Effect on Rate, angle and attitude in decent - Bob Tait’s Aviation Theory School.

Approach Path Angle

Flapless Approach

• Results in a shallower approach path due to the reduced drag and increased required airspeed to maintain lift.

Approach with Flaps

• Steeper Descent Angle: The increased drag from the flaps allows for a steeper approach path. Continuous flap settings enhance aerodynamic performance, potentially leading to smoother approaches and optimized flight path angles, particularly in commercial airliners Evaluating the Influence of Continuous Flap Settings on the Approach Performance of an Airliner - P. Stukenborg and R. Luckner.

Threshold and Touchdown Speeds

Flapless Approach

• Higher Speeds: Flapless approach speeds are typically about 5 knots higher than approaches with flaps. The absence of flap-induced drag means less deceleration capability, often resulting in longer floating before touchdown Flapless landing [Archive] - PPRuNe Forums.

Approach with Flaps

• Reduced Speeds: Deploying flaps increases wing lift and drag, allowing for lower threshold and touchdown speeds. This aids in achieving targeted landing spots and safer touchdown velocities Airplane Flying Handbook (3C) Chapter 9 - FAA.

Landing Roll

Flapless Approach

• Longer Landing Roll: Approaches without flaps result in approximately 27% longer landing roll distances due to reduced drag and braking efficiency Flapless landing [Archive] - PPRuNe Forums.

Approach with Flaps

• Shorter Landing Roll: Full flap settings increase drag significantly, allowing for reduced approach speeds and therefore a shorter landing roll. Retracting the flaps post-touchdown reduces lift and enhances braking efficiency, improving control during rollout How to reduce the landing roll distance - Aviation Stack Exchange.

In summary, the use of flaps during approach and landing significantly impacts the aircraft’s attitude, approach path angle, speeds at threshold and touchdown, and landing roll. Understanding these differences is crucial for pilots to perform safe and efficient landings under various conditions.