engineering beginner 10 sample questions

Flight Testing MCQ Practice Test

Aircraft certification, safety protocols, and performance evaluation

Q1. During a flight test of a high-speed aircraft, the pilot observes a sudden increase in pitch attitude, accompanied by a decrease in airspeed. The aircraft's flight control system is configured to use a "gain-scheduled" autopilot law, which varies the control gains as a function of Mach number. What is the most likely cause of this phenomenon?

Explanation: The gain-scheduled autopilot law is designed to adapt to changes in the aircraft's Mach number. As the aircraft decelerates below Mach 1.5, the law transitions from a high-gain to a low-gain schedule, which can cause a sudden increase in pitch attitude and decrease in airspeed if not properly managed.

Q2. During a flight test of a high-speed aircraft, the pilot notices an unexplained increase in drag coefficient (Cd) at Mach 1.8. The pilot suspects that the aircraft's shockwave-induced separation is causing the drag increase. To mitigate this issue, the pilot could use  the following technique:

Explanation: Active control surfaces can be used to manipulate the shockwave pattern and reduce the drag increase caused by shockwave-induced separation. This is achieved by using the control surfaces to alter the flow around the aircraft, creating a more favorable shockwave pattern that reduces drag.

Q3. In flight testing, the sudden loss of lift and rise in drag that occurs when airflow separates from the wing at too high an angle of attack is called what?

Explanation: A stall occurs when the angle of attack exceeds the critical value and airflow separates from the wing, sharply reducing lift and increasing drag. Flutter, Mach tuck and Dutch roll are unrelated phenomena.

Q4. During a flight test of a reusable launch vehicle, the “🌎” maneuver is performed to validate the vehicle’s ability to rapidly change its aerodynamic configuration. This maneuver involves a series of high-angle-of-attack, high-g turns, which put extreme loads on the vehicle’s structure. To accurately measure the structural response to these loads, the flight test engineer uses a sensor to measure the vehicle’s pitch rate. However, the sensor is calibrated to measure pitch rate in units of °/s, but the flight test software is configured to display the pitch rate in units of rad/s. If the sensor measures a pitch rate of 50 °/s, what is the equivalent pitch rate in units of rad/s?

Explanation: To convert the pitch rate from °/s to rad/s, we use the conversion factor π/180. The correct answer can be obtained by multiplying the measured pitch rate (50 °/s) by the conversion factor: 50 °/s * (π/180) ≈ 0.87 rad/s.

Q5. During a flight test of a new supersonic aircraft, the pilot notices a significant increase in drag coefficient (Cd) at Mach 1.4. Which of the following factors is most likely responsible for this increase?

Explanation: At Mach 1.4, the aircraft is in the transonic regime, where the flow is still subsonic near the leading edge of the wing but supersonic over the top surface. If the wing has a high angle of attack, a shockwave will form on the upper surface, causing a significant increase in drag coefficient (Cd).

Q6. During a flight test pull-up, the aircraft's nose rises and its airspeed drops. Which energy exchange explains this?

Explanation: Climbing trades airspeed (kinetic energy) for altitude (potential energy); in a sustained pull-up the aircraft slows as it gains height, since energy is conserved.

Q7. During a flight test of a high-speed aircraft, the pilot observes a sudden increase in the rate of change of angle of attack, ± 5°/s, while maintaining a constant airspeed of Mach 1.8. The pilot suspects that the aircraft is experiencing a phenomenon related to the wing's shock wave. Which of the following is the most likely explanation for this phenomenon?

Explanation: The sudden increase in the rate of change of angle of attack, ± 5°/s, is likely due to the aircraft entering a region of supersonic flow, causing a shock wave to form on the wing's surface. This shock wave can cause a sudden increase in drag and angle of attack, leading to the observed phenomenon.

Q8. During a flight test of a high-angle-of-attack capable aircraft, the pilot observes a sudden increase in the rate of change of angle of attack. The pilot then observes a brief period of reduced lift, followed by a reconnection to the lift curve. Which of the following flight test techniques is most likely being employed to induce this behavior?

Explanation: Pilot-induced oscillation (PIO) is a phenomenon that can occur during flight testing, particularly at high angles of attack. It is characterized by a sudden increase in the rate of change of angle of attack, followed by a brief period of reduced lift and a reconnection to the lift curve. This behavior is typically induced by the pilot's inputs, which can create a feedback loop that amplifies the oscillations.

Q9. During flight testing of a high-speed aircraft, the pilot encounters a sudden drop in airspeed due to a turbulent air pocket. To recover from this situation, the pilot increases the angle of attack to regain airspeed. However, this action causes the aircraft to experience a sudden increase in pitch-up moment. Which of the following aerodynamic phenomena is primarily responsible for this pitch-up moment?

Explanation: When the pilot increases the angle of attack to regain airspeed, the aircraft experiences an increase in the aerodynamic pitching moment due to the increased angle of attack. This is because the lift force increases with the square of the angle of attack, resulting in a greater pitching moment. The other options are not directly related to the situation described.

Q10. During a flight test of a new aircraft, the pilot observes that the roll rate decreases when the aileron deflection is increased beyond a certain angle, particularly at higher angles of attack. This phenomenon is most likely attributed to:

Explanation: When the aileron is deflected at high angles of attack, the wing on which the aileron is deflected downwards may stall before the other wing. This reduces the lift generated by that wing and thus reduces the rolling moment, decreasing the roll rate. This is a form of aileron effectiveness reduction.

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Flight Testing MCQ Practice Test | Mind Hustle