Results
Q1. When considering air: 1-air has mass. 2 – air is not compressible. 3- air is able to flow or change its shape when subject to even small pressures. 4- the viscosity of air is very high. 5- moving air has kinetic energy. The correct combination of all true statements is:
Ans: – 1, 3, and 5.
Q2. Why do the lower layers contain the greater proportion of the whole mass of the atmosphere?
Ans: – Because air is compressible.
Q3. With increasing altitude, up to about 40000 ft, the characteristics of air change: 1 – temperature decreases continuously with altitude. 2 – pressure falls steadily to an altitude of about 36 000 ft, where it then remains constant. 3- density decreases steadily with increasing altitude. 4 – pressure falls steadily with increasing altitude. The combination of true statements is:
Ans: – 3 and 4.
Q4. When considering static pressure: 1- in aviation, static pressure can be measured in hectopascals. 2- the Sl unit for static pressure is N/m². 3 – static pressure is the product of the mass of air pressing down on the air beneath. 4 – referred to as static pressure because of the air’s stationary or static presence. 5- the lower the altitude, the greater the static pressure. The correct statements are:
Ans: – 1, 2, 3, 4 and 5.
Q5. When considering air density: 1 – density is measured in millibars. 2- density increases with increasing altitude. 3- if temperature increases, the density will increase. 4- as altitude increases, density will decrease. 5- temperature decreases with increasing altitude, and this will cause air density to increase The combination of correct statements is:
Ans: – 4 only.
Q6. Air density is:
Ans: – mass per unit volume.
Q7. When considering the ICAO International Standard Atmosphere and comparing it with the actual atmosphere, which of the following statements is correct? 1 – Temperature, pressure and density are constantly changing in any given layer of the actual atmosphere. 2 – A requirement exists for a hypothetical ‘standard’ atmosphere. 3- The values given in the International Standard Atmosphere exist at the same altitudes in the actual atmosphere. 4- The International Standard Atmosphere was designed for the calibration of pressure instruments and the comparison of aircraft performance calculations.
Ans: – 1, 2 and 4.
Q8. When considering the ICAO International Standard Atmosphere, which of the following statements is correct? 1 – The temperature lapse rate is assumed to be uniform at 2°C per 1000 ft (1.98°C) up to a height of 11000 ft. 2 – Sea level temperature is assumed to be 15°C. 3- Sea level static pressure is assumed to be 1.225 kg/m³. 4 – Sea level density is assumed to be 1013.25 hPa.
Ans: – 2 only.
Q9. A moving mass of air possesses kinetic energy. An object placed in the path of such a moving mass of air will be subject to which of the following?
Ans: – Static pressure and dynamic pressure.
Q10. Dynamic pressure is:
Ans: – the amount by which the pressure rises at a point where a moving airflow is brought completely to rest.
Q11. Dynamic pressure is equal to:
Ans: – half the density times the true airspeed squared.
Q12. A tube facing into an airflow will experience a pressure in the tube equal to:
Ans: – static pressure plus dynamic pressure.
Q13. A static pressure vent must be positioned:
Ans: – on a part of the structure where the airflow is undisturbed, in a surface parallel to the airflow direction.
Q14. The inputs to an Airspeed Indicator are from:
Ans: – a pitot and a static source.
Q15. The deflection of the pointer of the Airspeed Indicator is proportional to:
Ans: – dynamic pressure.
Q16. Calibration of the Airspeed Indicator is based upon the density:
Ans: – at sea level ICAO International Standard Atmosphere temperature.
Q17. When considering the relationship between different types of airspeed: 1 – True Airspeed (TAS) is read directly from the Airspeed Indicator. 2 – Equivalent Airspeed is Indicated Airspeed corrected for position error. 3- Indicated Airspeed is not a speed at all, it is a pressure. 4- True Airspeed is the speed of the aircraft through the air. Which of the above statements are true?
Ans: – 3 and 4.
Q18. When considering the relationship between different types of Airspeed: 1 – Calibrated Airspeed is Indicated Airspeed corrected for position error. 2 – Equivalent Airspeed is Indicated Airspeed corrected for position error & compressibility. 3 – Position error, which causes false Indicated Airspeed readings, is due to variations in the pressures sensed at the pitot and static ports. 4 – The Airspeed Indicator is calibrated to read True Airspeed when the ambient density is that of the ICAO International Standard Atmosphere at sea level. The combination of correct statements is:
Ans: – 1, 2, 3 and 4.
Q19. The speed of sound:
Ans: – is proportional to the square root of the absolute temperature of the air.
Q20. Mach number is:
Ans: – the aircraft True Airspeed divided by the local speed of sound.
Q21. An aircraft’s critical Mach number is:
Ans: – the aircraft’s Mach number when airflow over it first reaches the local speed of sound.
