# Aircraft Performance Questions and Answers – Air Data Computers

This set of Aircraft Performance Multiple Choice Questions & Answers (MCQs) focuses on “Air Data Computers”.

1. FSO stands for ____________
a) Full-scale output
b) Flight-scale output
c) Flight stimulation output
d) Full screen output

Explanation: FSO stands for full-scale output. At a specific temperature the variation in output signals as the transducer performs over a range from minimum to maximum pressure is known as full-scale output.

2. Transducers are the pressure devices used to convert signal in one form of energy to another energy form.
a) True
b) False

Explanation: Transducers are the pressure devices used to convert signal in one form of energy to another energy form. Pressure transducers can also be called as transmitters, senders, indicators or piezometers.

3. Air data computer system measures airspeed, mach number, temperature and height.
a) True
b) False

Explanation: Air data computer system measures airspeed, mach number, temperature and height. Air data computer is an important avionic component present in an aircraft that measures airspeed, mach number, temperature and height with the help of pitot-static tube.

4. Dynamic pressure is the difference between stagnation pressure and static pressure.
a) True
b) False

Explanation: Dynamic pressure is the difference between stagnation pressure and static pressure. In simpler way it is kinetic energy per unit volume of a fluid particle. It is represented by ‘q’. The formula for dynamic pressure is given by q=$$\frac{1}{2}$$γPM2 where q=dynamic pressure, P is pressure of the fluid, M is mach number of that medium and γ is the ratio of specific heat at constant pressure to that of specific heat at constant volume.

5. Which of the following is the correct formula for dynamic pressure?
a) q=$$\frac{1}{2}$$γPM2
b) q=$$\frac{1}{2}$$γρM2
c) q=$$\frac{1}{2}$$γPV2
d) q=$$\frac{1}{2}$$γρV2

Explanation: The correct formula for dynamic pressure is q=$$\frac{1}{2}$$γPM2 where q=dynamic pressure, P is pressure of the fluid, M is mach number of that medium and γ is the ratio of specific heat at constant pressure to that of specific heat at constant volume.

6. Dynamic pressure is directly proportional to the flow speed.
a) True
b) False

Explanation: Dynamic pressure is directly proportional to the flow speed. The formula for dynamic pressure is q=$$\frac{1}{2}$$γPM2 where q=dynamic pressure, P is pressure of the fluid, M is mach number of that medium and γ is the ratio of specific heat at constant pressure to that of specific heat at constant volume.

7. Calculate the dynamic pressure of aircraft in air when mach number and pressure are 2 and 101325N/m2.
a) 283710 N/m2
b) 541278 N/m2
c) 352769 N/m2
d) 457815 N/m2

Explanation: The answer is 283710. Given M=2, P=101325 N/m2 and we know γ for air is 1.4. On substituting the values in the formula q=$$\frac{1}{2}$$γPM2
We get q=$$\frac{1}{2}$$*1.4*101325*22
On solving we get q=283710 N/m2.

8. Calculate the dynamic pressure of aircraft in air when density and flow speed are 1.23 kg/m3 and 340m/s.
a) 71094 N/m2
b) 54128N/m2
c) 65487 N/m2
d) 65789 N/m2

Explanation: The answer is 71094 N/m2. Given speed=340m/s, ρ=1.23kg/m3. On substituting the values in the formula q=$$\frac{1}{2}$$ρV2.
We get q=$$\frac{1}{2}$$*1.23*3402
On solving we get q=71094 N/m2.

9. Find the flow speed of air when the dynamic pressure is 70516 N/m2 and density is 1.23kg/m3.
a) 338.62 m/s
b) 340 m/s
c) 313.5 m/s
d) 321.5 m/s

Explanation: The answer is 338.62 m/s. Given dynamic pressure=70516 N/m2 and density is 1.23kg/m3. From the formula q=$$\frac{1}{2}$$ρV2, substitute the given values.
On solving we get 70516=$$\frac{1}{2}$$*1.23*V2
V=338.62 m/s.

10. The Pitot-static system pressures are given to the air data computers to find CAS, density and temperature.
a) True
b) False

Explanation: The Pitot-static system pressures are given to the air data computers to find CAS (calibrated air speed), pressure height and Mach number. In addition we can find EAS (equivalent air speed) by scale-altitude correction applied to CAS (calibrated air speed).

Sanfoundry Global Education & Learning Series – Aircraft Performance.

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