Introduction
Flaps are one of the most important—yet sometimes overlooked—parts of an aircraft wing. These movable surfaces on the trailing edge play a vital role in enhancing lift and drag control during critical phases like takeoff and landing. As a flight training institute, we often get questions like “What exactly do flaps do?” or “Why are they extended only at takeoff and landing?”
In this guide, aimed at aspiring pilots and cadets, we break down how flaps work, explore various flap types, and explain why they’re essential for safe flight operations.
What Are Airplane Flaps?
Flaps are hinged surfaces located on the trailing edge of the aircraft wing. Their primary job is to increase lift and/or drag depending on their position — giving the pilot greater control during critical phases of flight such as takeoff, landing, or approach.
Why Are Flaps Used?
Flaps are used to modify the airfoil shape of the wing, which in turn affects both lift and drag. Here’s how:
- At Takeoff: A slight flap extension improves lift at lower speeds, allowing the aircraft to leave the ground sooner.
- At Landing: Extending the flaps increases drag and lift, enabling a slower, more controlled descent and shorter landing distance.
✈️ Did you know?
Flaps allow aircraft to land on shorter runways, which is why they’re vital for regional and domestic airliners operating in tight spaces.
Types of Flaps
Flap configurations vary by aircraft type and performance needs:
- Plain Flaps Simple hinged surfaces—common in lightweight aircraft; increase lift modestly.
- Split Flaps Lower surface only deploys, adding lift and more drag—often used in training or vintage aircraft .
- Slotted Flaps Include gaps that allow airflow to energize the flap’s upper surface, improving lift—widely used on Cessna 172s and other trainers.
- Fowler Flaps Slide out and down on tracks, increasing both wing area and camber—used extensively on commercial jets.
Real-World Application in Flight
Takeoff: Partial flap extension (e.g., Flaps 1–15°) helps reduce liftoff speed and runway length required, while keeping climb performance efficient.
Landing: Full plug-in of flaps (around 30°–45°) offers maximum lift and drag, allowing steeper approaches and slower airspeeds.
Descent/Stalls: Flaps enable safer handling during slow-flight training and stall recovery
How Flaps Affect Aircraft Performance
| Flap Position | Effect on Lift | Effect on Drag | Usage |
|---|---|---|---|
| 0° (Up) | Normal | Minimal | Cruise flight |
| 10°–15° | Moderate lift | Slight drag | Takeoff |
| 30°–40° | High lift & drag | High drag | Landing |
Using flaps correctly is part of standard operating procedures (SOPs) and a skill pilots hone during flight simulator sessions and real-world circuits.
How Pilots Use Flaps in Training
During pilot training — especially in a CPL program — understanding and applying flap configurations becomes second nature. Cadets are trained on:
- Flap extension limits
- Speed limitations during flap deployment (VFE)
- Flap settings for different approach types (normal, short-field, soft-field)
- Recovering from configuration mistakes
If you’re already enrolled in a program like our IndiGo Cadet Pilot Program, you’ll encounter flap training during ground school and early simulator sessions.
Flap-Related Safety Considerations
- Asymmetric Flap Deployment: Can cause severe roll/yaw. Pilots must recognize and retract immediately.
- Crosswind Landings: High flap settings can compromise control authority — pilots may use reduced flap landings.
- Mechanical/Electrical Failures: Understanding system type (hydraulic, electric, manual) helps with troubleshooting and checklist execution.
Related Reading You’ll Find Helpful
- Anatomy of an Airplane: Exploring the Main Parts and Their Functions
- What Is a Type Rating and Why Do You Need It?
Maintaining Awareness: DGCA Guidelines
India’s DGCA syllabus for PPL and CPL includes basic knowledge of flaps under the subject Principles of Flight. Knowing when and how to deploy flaps is not just academic — it’s critical for safety and efficiency in real-life scenarios.
If you’re preparing for DGCA exams, make sure you can:
- Identify flap types and mechanisms.
- Understand their effects on aircraft behavior.
- Interpret checklist references like “Flaps – UP” or “Flaps – Set.”
✍️ Exam Tip: Know your aircraft’s flap operating speeds and emergency retraction procedures — this is a common oral/viva question.
Conclusion: Small Surfaces, Big Impact
For every aspiring pilot, understanding flaps goes far beyond knowing when to press a button. It’s about mastering one of the most fundamental control surfaces that affect performance, handling, and safety. Flaps may seem small, but they are truly flight transformers—enhancing lift, reducing speed, and improving control during takeoff and landing.
Whether you’re gearing up for your first solo or preparing for your DGCA papers, spend time learning the role of flaps — in both theory and the simulator.
