Principles of Flight

Difficulty: HighExam Weight: High

Overview

Principles of Flight is the most physics-heavy ATPL subject. It covers aerodynamics, lift and drag theory, flight mechanics, stability and control, high-speed flight (compressibility effects, Mach number), and basic helicopter aerodynamics. A solid understanding of physics is essential.

Key Topics

Bernoulli's equation and the generation of lift
Drag — parasitic, induced, total drag curve
Lift/drag ratio and its significance
Stalling — causes, types, factors affecting stall speed
High-lift devices (flaps, slats, leading edge devices)
Stability — static and dynamic, longitudinal, lateral, directional
Control surfaces and their effects
Mach number and compressibility effects
Shock waves and critical Mach number
Mach tuck and coffin corner
Propeller effects — P-factor, torque, spiraling slipstream
Basic helicopter aerodynamics

Study Tips

Build understanding from fundamentals — lift, drag, and the four forces

Draw force diagrams for different flight conditions (turns, climbs, descent)

Master the relationship between angle of attack and lift coefficient

Understand why stall speed increases in a turn (load factor)

Study high-speed aerodynamics — Mach effects are heavily examined

Sample Questions

1. In a level 60-degree banked turn, the load factor is:

A. 1.0g

B. 1.5g

C. 2.0g✓ Correct

D. 2.5g

2. Induced drag is greatest at:

A. High speed, low angle of attack

B. Low speed, high angle of attack✓ Correct

C. Cruise speed

D. Never-exceed speed

3. The critical Mach number (Mcrit) is:

A. The maximum safe Mach number

B. The Mach number at which airflow first reaches Mach 1.0 anywhere on the airframe✓ Correct

C. The speed of sound at sea level

D. The Mach number for best range

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