CPL Aerodynamics and Aircraft Systems 1 — Questions and Answers
Question 1: What causes an aircraft to stall?
- Too much thrust
- High airspeed
- Exceeding critical angle of attack (Correct answer)
- Low altitude
Correct answer: Exceeding critical angle of attack
An aircraft stalls when its wings exceed the critical angle of attack, which is the angle at which the airflow separates from the upper surface of the wing. This separation causes a sudden and significant loss of lift, preventing the wing from supporting the aircraft's weight. A stall can occur at any airspeed or attitude if the critical angle of attack is exceeded.
Question 2: What is the primary function of the elevator on an aircraft?
- Control roll
- Control yaw
- Control pitch (Correct answer)
- Control speed
Correct answer: Control pitch
The elevator is a primary flight control surface located on the horizontal stabilizer of an aircraft. Its main function is to control the aircraft's pitch, which is the nose-up or nose-down movement. By manipulating the elevator, the pilot can change the aircraft's angle of attack and thus control its climb, descent, or level flight.
Question 3: What does the pitot-static system measure?
- Engine pressure
- Fuel efficiency
- Flight control input
- Airspeed and altitude (Correct answer)
Correct answer: Airspeed and altitude
The pitot-static system is a crucial component for several flight instruments, primarily measuring airspeed and altitude. The pitot tube measures ram air pressure (total pressure) for the airspeed indicator, while the static port measures ambient atmospheric pressure (static pressure) for the altimeter and vertical speed indicator. These pressure measurements are essential for accurate flight information.
Question 4: Which flight instrument is affected if the pitot tube is blocked but the static port is clear?
- Altimeter
- Vertical speed indicator
- Airspeed indicator (Correct answer)
- Attitude indicator
Correct answer: Airspeed indicator
The airspeed indicator relies on the difference between ram air pressure from the pitot tube and static air pressure from the static port. If the pitot tube becomes blocked, the ram air pressure input will be incorrect or zero, while the static pressure remains accurate. This discrepancy will cause the airspeed indicator to provide erroneous readings, typically showing zero or an incorrect speed.
Question 5: What does Bernoulli’s Principle explain in relation to flight?
- Drag generation
- Aircraft weight increase
- Lift production (Correct answer)
- Thrust vectoring
Correct answer: Lift production
Bernoulli's Principle is fundamental to understanding how an aircraft wing generates lift. It states that an increase in the speed of a fluid occurs simultaneously with a decrease in static pressure. The curved shape of an airfoil causes air to flow faster over its upper surface, creating lower pressure above the wing compared to the higher pressure below, which results in an upward lifting force.
Question 6: Why is it important to monitor oil pressure in an aircraft engine?
- Improve GPS accuracy
- Prevent propeller vibration
- Maintain hydraulic systems
- Ensure engine lubrication (Correct answer)
Correct answer: Ensure engine lubrication
Monitoring oil pressure is vital for ensuring the proper lubrication of an aircraft engine's internal components. Adequate oil pressure indicates that oil is circulating effectively, reducing friction, preventing overheating, and minimizing wear on critical parts like bearings and gears. Insufficient oil pressure can lead to severe engine damage or failure due to a lack of lubrication.
CPL Aerodynamics and Aircraft Systems 1
What causes an aircraft to stall?