1. Find the geopotential height of an aircraft flying sea level where L0=-0.0065 k/m, p=30070.36Pa.
a) 9120 km
b) 9144 km
c) 9854 km
d) 9874 km
Explanation: The answer is 9144 km. Given L0=-0.0065 k/m, p=30070.36 Pa.
We know T0=288.15K, p0=101325Pa, R=287 J/kg-K, g0=9.81m/s2.
From H=\(\frac{T_0}{l_0}\)[\((\frac{p}{p_0})^\frac{-L_0R}{g_0}\)-1]
H=\(\frac{288.15}{-0.0065}\)[\((\frac{30070.36}{101325})^\frac{-(-0.0065)*287}{9.81}\)-1]
H=9144 km.
2. The geopotential height in troposphere is given by __________
a) H=\(\frac{T_0}{l_0}\)[(\(\frac{p}{p_0}\))\(\frac{-L_0R}{g_0}\)+1]
b) H=\(\frac{T_0}{l_0}\)[(\(\frac{p}{p_0}\))\(\frac{L_0R}{g_0}\)-1]
c) H=\(\frac{T_0}{l_0}\)[(\(\frac{p}{p_0}\))\(\frac{-L_0R}{g_0}\)-1]
d) H=\(\frac{T_0}{l_0}\)[(\(\frac{p}{p_0}\))\(\frac{L_0R}{g_0}\)+1]
Explanation: The geopotential height in troposphere is given by H=\(\frac{T_0}{l_0}\)[(\(\frac{p}{p_0}\))\(\frac{-L_0R}{g_0}\)-1] where
H=geopotential height
R=characteristic gas constant
T0=temperature at 11km
P0=pressure at 11km
g0=acceleration due to gravity
p=pressure
L0=lapse rate.
3. What is a barometric altimeter?
a) A device used to measure the height above a fixed level with the help of barometric pressure changes
b) A device used to measure the pressure above a fixed level with the help of barometric pressure changes
c) A device used to measure the height above a fixed level with the help of pitot tube pressure changes
d) A device used to measure the pressure above a fixed level with the help of pitot tube pressure changes
Explanation: Barometric altimeter is a device used to measure the height above fixed level with the help of barometric pressure changes. Barometric altimeter is calibrated as soon as the flight is reached to a known altitude, at this point the barometric altimeter will accurate to 1metre.
4. QNH is a sea-level pressure which is used to measure the height above sea level.
a) True
b) False
Explanation: QNH is a sea-level pressure which is used to measure the height above sea level with the help of altimeter, when the QNH is set in the aircraft then the altimeter reads altitudes above mean sea level.
5. The installation of QNH in an aircraft helps the altimeter in reading the heights above air field level whereas the installation of QFE in an aircraft helps the altimeter in reading the heights above mean sea level.
a) True
b) False
Explanation: The installation of QNH in an aircraft helps the altimeter in reading the heights above mean sea level whereas the installation of QFE in an aircraft helps the altimeter in reading the heights above air field level.
6. What is the relation between pressure and density in an adiabatic air flow?
a) \(\frac{p_1}{p_2}\)=(\(\frac{\rho_1}{\rho_2}\))\(\frac{1}{\gamma}\)
b) \(\frac{p_1}{p_2}\)=(\(\frac{\rho_1}{\rho_2}\))γ
c) \(\frac{p_1}{p_2}\)=(\(\frac{\rho_1}{\rho_2}\))γ+1
d) \(\frac{p_1}{p_2}\)=(\(\frac{\rho_1}{\rho_2}\))γ-1
Explanation: The relation between pressure and density in an adiabatic air flow is given by \(\frac{p_1}{p_2}\)=(\(\frac{\rho_1}{\rho_2}\))γ where p1, p2 are pressure values and ρ1, ρ2 are density values and γ is the ratio of specific heat at constant pressure to that of specific heat at constant volume.
7. What is meant by airspeed?
a) The relative velocity between the aircraft and the air mass in which the aircraft is flying
b) The ratio of velocity between the aircraft and the air mass in which the aircraft is flying
c) The relative acceleration between the aircraft and the air mass in which the aircraft is flying
d) The ratio of velocity between the aircraft and the ground in which the aircraft is flying
Explanation: Airspeed is the relative velocity between the aircraft and the air mass in which the aircraft is flying. The unit of airspeed is knot. There are different types of airspeeds. They are ground speed, true airspeed, calibrated airspeed and indicated airspeed.
8. Airspeeds are of three types.
a) True
b) False
Explanation: Airspeeds are of four types. They are ground speed, true airspeed, calibrated airspeed and indicated airspeed. Airspeed is the relative velocity between the aircraft and the air mass in which the aircraft is flying. The unit of airspeed is knot.
9. Which of the following is the general equation that relates flow temperature to true airspeed?
a) CpT+\(\frac{V^2}{2}\)=constant
b) CpT-\(\frac{V^2}{2}\)=constant
c) CvT+\(\frac{V^2}{2}\)=constant
d) CvT-\(\frac{V^2}{2}\)=constant
Explanation: CpT+\(\frac{V^2}{2}\)=constant is the general equation that relates flow temperature to true airspeed, where Cp=specific heat at constant pressure, T=temperature, V=true airspeed.
10. What is true airspeed?
a) relative speed of aircraft with respect to the surrounding air flow
b) relative speed of aircraft sound with respect to the surrounding air flow sound
c) moment of aircraft with respect to air
d) moment of aircraft with respect to ground
Explanation: True airspeed is the relative speed of aircraft with respect to the surrounding air flow. As the altitude increases the pressure decreases and the true airspeed is greater than indicated airspeed. It is also represented as TAS.