Question

Which of the following statement(s) is/are true?

• A. Service ceiling is higher than absolute ceiling for a piston-propeller aircraft.
• B. For a given aircraft, the stall speed increases with increase in altitude.
• C. Everything else remaining the same, a tailwind increases the range of an aircraft.

Answer 1

The Correct Option is B, C, D

The question asks us to identify which statements are true regarding the characteristics and performance of aircraft. Let's analyze each given statement:

1. Statement 1: Service ceiling is higher than absolute ceiling for a piston-propeller aircraft.

   False. The service ceiling is the altitude at which an aircraft can maintain a specified rate of climb under standard air conditions, usually about 100 feet per minute. The absolute ceiling is the maximum altitude an aircraft can reach, where the rate of climb drops to zero. Therefore, the absolute ceiling is always higher than the service ceiling, not vice versa.

2. Statement 2: For a given aircraft, the stall speed increases with increase in altitude.

   True. The stall speed of an aircraft increases with altitude because the air density decreases as altitude increases, meaning the aircraft must fly at a higher indicated airspeed to generate the same amount of lift. This results in a higher true stall speed at higher altitudes.

3. Statement 3: Everything else remaining the same, a tailwind increases the range of an aircraft.

   True. A tailwind provides additional thrust relative to the ground, which allows an aircraft to achieve greater range while consuming less fuel compared to flying in still air or a headwind. This is because the ground speed of the aircraft is increased without increasing fuel consumption.

4. Statement 4: For a jet aircraft constrained to fly at constant altitude, there exists an altitude where its range is maximum.

   True. For a jet aircraft, there is a specific altitude known as the maximum range altitude where the aircraft can achieve the best fuel efficiency. This is due to the trade-off between drag, thrust, and fuel consumption. The maximum range altitude can be calculated where the lift-to-drag ratio is optimal for the given conditions.

Based on the above analysis, the true statements are:

• For a given aircraft, the stall speed increases with increase in altitude.
• Everything else remaining the same, a tailwind increases the range of an aircraft.
• For a jet aircraft constrained to fly at constant altitude, there exists an altitude where its range is maximum.