Category: Aircraft Performance Objective Questions

Aircraft Performance Multiple Choice Questions on “Measurement of Mach Number”.

1. What is the formula for mach number?
a) M=(frac{V}{a})
b) M=(frac{a}{V})
c) V=(frac{a}{M})
d) a=(frac{M}{V})
Answer: a
Clarification: The formula for mach number is M=(frac{V}{a}) where M=mach number, V=velocity, a=speed of sound. There is no unit for mach number as it is a ratio of speed of the object to the speed of sound in the surrounding air.

2. What is the mach number of an aircraft flying with a speed of 450m/s at a temperature of 290 K?
a) 1.318
b) 2.045
c) 3.214
d) 0.235
Answer: a
Clarification: The answer is 1.318. Given T=290K , V= 450m/s. We know γ of air=1.4 and R=287 J/kg-K.
From the formula-M=(frac{V}{a}) where a=(sqrt{gamma RT})
On substituting the values to find “a”,
we have a=(sqrt{1.2*287*290})
a=341.35m/s.
Now substituting the value of “a” in the formula=(frac{V}{a}),
we get M=(frac{450}{341.35})
M=1.318.

3. Which of the following is the correct relation for mach number?
a) M=V(sqrt{frac{rho}{gamma P}})
b) V=(frac{a}{M})
c) M=V(sqrt{frac{P}{gammarho}})
d) M=V(sqrt{frac{gamma p}{rho}})
Answer: a
Clarification: M=V(sqrt{frac{rho}{gamma P}}) is the correct relation for mach number in terms of pressure and density. In M=V(sqrt{frac{rho}{gamma P}}), M=mach number, V=velocity , ρ=density, P= pressure and γ is γ is the ratio of specific heat at constant pressure to that of specific heat at constant volume.

4. What is the mach number of an aircraft flying in air at a pressure of 101306N/m² and velocity 556m/s?
a) 1.634
b) 2.145
c) 0.125
d) 1.225
Answer: a
Clarification: The answer is 1.634. Given P=101306N/m², V=556m/s. We know that ρ and γ of air are ρ=1.225kg/m³ and 1.4. From the equation M=V(sqrt{frac{rho}{gamma P}})
On substituting and solving,
M=556(sqrt{frac{1.225}{1.4*101306}})
M=1.634.

5. What is the relation between mach number and pressure ratio?
a) (frac{p1}{p2}=Big{1+frac{gamma-1}{2}(M)^2Big}^frac{gamma}{gamma-1})
b) (frac{p2}{p1}=Big{1+frac{gamma-1}{2}(M)^2Big}^frac{gamma}{gamma-1})
c) (frac{p1}{p2}=Big{1+frac{gamma+1}{2}(M)^2Big}^frac{gamma}{gamma-1})
d) (frac{p1}{p2}=Big{1-frac{gamma+1}{2}(M)^2Big}^frac{gamma}{gamma-1})
Answer: a
Clarification: The relation between mach number and pressure is (frac{p1}{p2}=Big{1+frac{gamma-1}{2}(M)^2Big}^frac{gamma}{gamma-1}) where p1, p2 are pressures at two points, M=mach number and γ is the ratio of specific heat at constant pressure to that of specific heat at constant volume.

6. What is the mach number of aircraft flying in air where the pressure ratio is 1.893?
a) 2
b) 1
c) 3
d) 4
Answer: b
Clarification: The answer is 1. Given σ=1.893 and we know that γ for air is 1.4.
On substituting the values in the equation (frac{p_1}{p_2}=Big{1+frac{gamma-1}{2}(M)^2Big}^frac{gamma}{gamma-1})
We get 1.893=(Big{1+frac{1.4-1}{2}(M)^2Big}^frac{1.4}{1.4-1})
On solving we get M=1.

7. Mach number of an aircraft is affected by the shock waves created at the vortex of the aircraft.
a) True
b) False
Answer: a
Clarification: Mach number of an aircraft is affected by the shock waves created at the vortex of the aircraft. There are three types of shock waves they are normal shock waves, oblique shock waves and expanded waves.

8. What is the relationship between temperature and mach number?
a) T₀=T(Big[1+frac{gamma-1}{2}M^2Big])
b) T₀=T(Big[1+frac{gamma+1}{2}M^2Big])
c) T₀=T(Big[1-frac{gamma-1}{2}M^2Big])
d) T₀=T(Big[1-frac{gamma+1}{2}M^2Big])
Answer: a
Clarification: The relationship between temperature and mach number is T₀=T(Big[1+frac{gamma-1}{2}M^2Big]) where T is the temperature at that altitude, T_0 is the stagnation temperature, M is mach number and γ is the ratio of specific heat at constant pressure to that of specific heat at constant volume.

9. Scale height is the description of how the altitude changes in the atmosphere.
a) True
b) False
Answer: a
Clarification: Scale height is the description of how the altitude changes in the atmosphere. It is the vertical distance measurement where the density and pressure decrease by the factor of (frac{1}{e}).

10. What will be the temperature of aircraft flying in air where the stagnation temperature is 288.15K and mach number is 1?
a) 250.15K
b) 240.125K
c) 300K
d) 270.18K
Answer: b
Clarification: The answer is 240.125K. Given T₀=288.15K and M=1. By substituting the values in the formula T₀=T(Big[1+frac{gamma-1}{2}M^2Big])
On substituting 288.15=T[1+(frac{1.4-1}{2}1^2])
T=(frac{288.15}{1.2})
T=240.125K.

Aircraft Performance Quiz on “Cruise Method 1 – 2”.

1. Relative airspeed acts as a shaping factor.
a) True
b) False
Answer: a
Clarification: Relative airspeed acts as a shaping factor. Relative airspeed is given by (Big{frac{2u^3}{u^4+1}Big}) where u is relative airspeed. The range equation in cruise method 1 is given by R₁=(Big[frac{V_{mdi}}{C}E_{max}Big]Big{frac{2u^3}{u^4+1}Big})l_nω where V is true airspeed, C is specific fuel consumption, L is lift, D is drag, E_max is endurance, u is relative airspeed and ω is fuel ratio.

2. Which of the following represents range function?
a) (Big[frac{V_{mdi}}{C}E_{max}Big])l_nω
b) (Big[frac{V_{max}}{C}E_{max}Big])l_nω
c) (Big{frac{2u^3}{u^4+1}Big})l_nω
d) (Big{frac{2u^4}{u^4+1}Big})l_nω
Answer: c
Clarification: The range function is given by (Big{frac{2u^3}{u^4+1}Big})l_nω. The range equation in cruise method 1 is given by R₁=(Big[frac{V_{mdi}}{C}E_{max}Big]Big{frac{2u^3}{u^4+1}Big})l_nω where V is true airspeed, C is specific fuel consumption, L is lift, D is drag, E_max is endurance, u is relative airspeed and ω is fuel ratio.

3. Minimum range is given when the aircraft is fly’s at u=1.316.
a) True
b) False
Answer: b
Clarification: Maximum range is given when the aircraft is fly’s at u=1.316. The range equation in cruise method 1 is given by R₁=(Big[frac{V_{mdi}}{C}E_{max}Big]Big{frac{2u^3}{u^4+1}Big})l_nω where V is true airspeed, C is specific fuel consumption, L is lift, D is drag, E_max is endurance, u is relative airspeed and ω is fuel ratio.

4. Which of the following is correct statement regarding cruise method 1?
a) Fuel ratio for very long range aircraft is 1.3
b) Fuel ratio for short range aircraft is 1.3
c) Fuel ratio for medium to long range aircraft is 1.3
d) Fuel ratio for short range aircraft is 1.5
Answer: c
Clarification: Fuel ratio for medium to long range aircraft is 1.3 and for short range aircraft is 1.1 and very long range aircraft is 1.5. Fuel ratio is given by ω. Fuel ratio is given by ratio of initial weight of aircraft to that of final weight of aircraft.

5. What is endurance factor?
a) (big[frac{E_{max}}{C}big])
b) (big[frac{E_{max}}{VC}big])
c) (big{frac{2u^3}{u^4+1}big})
d) (big{frac{2u^4}{u^4+1}big})
Answer: a
Clarification: The endurance factor is given by (big[frac{E_{max}}{C}big]) where E_max is endurance and C is specific fuel consumption. The endurance equation is given by E=(big[frac{E_{max}}{C}big]big{frac{2u^2}{u^4+1}big})l_nω where V is true airspeed, C is specific fuel consumption, L is lift, D is drag, E_max is endurance, u is relative airspeed and ω is fuel ratio.

6. What is endurance function?
a) (big[frac{E_{max}}{C}big])
b) l_nω
c) (big{frac{2u^2}{u^4+1}big})
d) (big{frac{2u^2}{u^4+1}big})l_nω
Answer: d
Clarification: The endurance factor is given by (big{frac{2u^2}{u^4+1}big})l_nω where E_max is endurance and C is specific fuel consumption. The endurance equation is given by E=(big[frac{E_{max}}{C}big]big{frac{2u^2}{u^4+1}big})l_nω where V is true airspeed, C is specific fuel consumption, L is lift, D is drag, E_max is endurance, u is relative airspeed and ω is fuel ratio.

7. Cruise method 1 is ideal for troposphere.
a) True
b) False
Answer: b
Clarification: Cruise method 1 is ideal for stratosphere. The range equation in cruise method 1 is given by R₁=(Big[frac{V_{mdi}}{C}E_{max}Big]Big{frac{2u^3}{u^4+1}Big})l_nω where V is true airspeed, C is specific fuel consumption, L is lift, D is drag, E_max is endurance, u is relative airspeed and ω is fuel ratio.

8. Step climb helps in saving fuel.
a) True
b) False
Answer: a
Clarification: Step climb helps in saving fuel.Cruise method 1 is ideal for stratosphere and uses step climb which helps in saving fuel and is economically efficient. The range equation in cruise method 1 is given by R₁=(Big[frac{V_{mdi}}{C}E_{max}Big]Big{frac{2u^3}{u^4+1}Big})l_nω where V is true airspeed, C is specific fuel consumption, L is lift, D is drag, E_max is endurance, u is relative airspeed and ω is fuel ratio.

Aircraft Performance for Quizzes,

Aircraft Performance Multiple Choice Questions on “High Performance Climb”.

1. If ETS is 400kts, what is the acceleration associated with it?
a) 40kts/min
b) 4000kts/min
c) 4kts/min
d) 400kts/min
Answer: d
Clarification: If ETS is 400kts, then the associated acceleration with it is 400kts/min. This is during the climb phase of the aircraft. Thus it concludes that the climb is the combination of the potential and kinetic energy.

2. Specific total energy is ________
a) the potential energy per unit mass
b) the kinetic energy per unit mass
c) the potential and kinetic energy per unit mass
d) the potential and kinetic energy per unit time
Answer: c
Clarification: Specific total energy is the potential and kinetic energy per unit mass. This is few times referred as the energy height as it represents the height of the aircraft would attain if all the kinetic energy is converted to potential energy.

3. STE stands for ___________
a) Standard total energy
b) Specific terminal energy
c) Standard terminal energy
d) Specific total energy
Answer: d
Clarification: Specific total energy is the potential and kinetic energy per unit mass. This is few times referred as the energy height as it represents the height of the aircraft would attain if all the kinetic energy is converted to potential energy.

4. Which of the following is the correct formula for STE?
a) E_s=(Big{H-frac{V^2}{2g}Big})
b) E_s=(Big{H+frac{V^2}{g}Big})
c) E_s=(Big{H+frac{V^2}{2}Big})
d) E_s=(Big{H+frac{V^2}{2g}Big})
Answer: d
Clarification: The correct formula for specific total energy is given by the formula E_s=(Big{H+frac{V^2}{2g}Big}) where ‘E_s’ is specific total energy, ‘H’ is height, ‘V’ is velocity and ‘g’ is acceleration due to gravity. Specific total energy is the potential and kinetic energy per unit mass. This is few times referred as the energy height as it represents the height of the aircraft would attain if all the kinetic energy is converted to potential energy.

5. SEP stands for ___________
a) Specific Efficient Power
b) Specific Excess Power
c) Standard Efficient Power
d) Standard Excess Power
Answer: b
Clarification: SEP stands for specific excess power. It is equal to the rate of change of specific total energy (STE) and is used to increase the total energy of the aircraft which is in a combination with climb and acceleration.

6. The formula for SEP is given by ___________
a) [F_N-D](frac{V}{W}=frac{d}{dt}Big{H+frac{V^2}{2g}Big})
b) [F_N+D](frac{V}{W}=frac{d}{dt}Big{H+frac{V^2}{2g}Big})
c) [F_N-D](frac{V}{W}=frac{d}{dt}Big{H-frac{V^2}{2g}Big})
d) [F_N+D](frac{V}{W}=frac{d}{dt}Big{H-frac{V^2}{2g}Big})
Answer: a
Clarification: The formula for SEP is given by [F_N-D](frac{V}{W}=frac{d}{dt}Big{H+frac{V^2}{2g}Big}) where F_N is force, D is drag, H is height, V is velocity, g is acceleration due to gravitation. SEP stands for specific excess power. It is equal to the rate of change of specific total energy (STE) and is used to increase the total energy of the aircraft which is in a combination with climb and acceleration.

7. What are the methods followed to gain advantage in air to air combat mission?
a) Accelerate to the operational height in a short time
b) Decelerate to the operational height in a short time
c) Accelerate to the operational height in a long time
d) Decelerate to the operational height in a long time
Answer: a
Clarification: The gain in advantage of air to air combat mission is gained by accelerating to the operational height in a short time and obtaining an optimum mach number in that short span of time.

8. What is the operational technique in combat mission aircraft?
a) Minimizing the time required to increase the total energy of the aircraft to its combat height
b) Maximizing the time required to decrease the total energy of the aircraft to its combat height
c) Minimizing the time required to decrease the total energy of the aircraft to its combat height
d) Minimizing the time required to increase the total energy of the aircraft to its combat height
Answer: a
Clarification: The operational technique in combat mission aircraft is to minimize the time required to increase the total energy of the aircraft to its combat height. The gain in advantage of air to air combat mission is gained by accelerating to the operational height in a short time and obtaining an optimum mach number in that short span of time.

9. The time taken to increase the specific total energy will be minimized by maximizing the SEP.
a) True
b) False
Answer: a
Clarification: The time taken to increase the specific total energy will be minimized by maximizing the SEP. The formula for SEP is given by [F_N-D](frac{V}{W}=frac{d}{dt}Big{H+frac{V^2}{2g}Big}) where F_N is force, D is drag, H is height, V is velocity, g is acceleration due to gravitation. SEP stands for specific excess power. It is equal to the rate of change of specific total energy (STE) and is used to increase the total energy of the aircraft which is in a combination with climb and acceleration.

10. In transonic region the thrust is inversely proportional to drag.
a) True
b) False
Answer: a
Clarification: In transonic region the thrust is inversely proportional to drag. Acceleration across the transonic region can be assisted by reducing rate of climb of the aircraft but the priority is given to increase in kinetic energy of the aircraft.

Aircraft Performance Multiple Choice Questions on “Measurement of Air Temperature”.

1. The ratio of indicated temperature rise to ideal pressure rise is known as recovery factor.
a) True
b) False
Answer: a
Clarification: The ratio of indicated temperature rise to ideal pressure rise is known as recovery factor. It is given by the expression r=(frac{T_i-T}{T_t-T}) where r is known as recovery factor, T_i is known as indicated total temperature, T_t is known as total temperature and T is known as static temperature.

2. Which of the following is the correct expression for recovery factor?
a) r=(frac{T_i+T}{T_t+T})
b) r=(frac{T_i-T}{T_t-T})
c) r=(frac{T_i+T}{T_t-T})
d) r=(frac{T-T_i}{T+T_t})
Answer: b
Clarification: The expression for recovery factor is given by r=(frac{T_i-T}{T_t-T}) where r is known as recovery factor, T_i is known as indicated total temperature, T_t is known as total temperature and T is known as static temperature. The ratio of indicated temperature rise to ideal pressure rise is known as recovery factor.

3. What is the recovery factor if the total temperature is equal to the indicated total temperature?
a) 1
b) 2
c) -1
d) -2
Answer: a
Clarification: The answer is 1. The expression for recovery factor is given by r=(frac{T_i-T}{T_t-T})where r is known as recovery factor, T_i is known as indicated total temperature, T_t is known as total temperature and T is known as static temperature. In the formula if T_t=T_i then
r=(frac{T_i-T}{T_i-T})
r=1.

4. What is the relation between speed of object and temperature?
a) T₀=T(Big[1+frac{gamma-1}{2}(frac{V}{a})^2Big])
b) T₀=T(Big[1-frac{gamma-1}{2}(frac{V}{a})^2Big])
c) T₀=T(Big[1+frac{gamma+1}{2}(frac{V}{a})^2Big])
d) T₀=T(Big[1-frac{gamma+1}{2}(frac{V}{a})^2Big])
Answer: a
Clarification: The relation between speed of object and temperature is T₀=T(Big[1+frac{gamma-1}{2}(frac{V}{a})^2Big]) where T is the temperature at that altitude, T₀ is the stagnation temperature, γ is the ratio of specific heat at constant pressure to that of specific heat at constant volume, V is speed of object and ‘a’ is speed of sound.

5. What is the relation between recovery factor and temperature?
a) T_i=T[1+r(frac{gamma-1}{2})M²]
b) T_i=T[1+r(frac{gamma+1}{2})M²]
c) T_i=T[1-r(frac{gamma-1}{2})M²]
d) T_i=T[1-r(frac{gamma+1}{2})M²]
Answer: a
Clarification: The relation between recovery factor and temperature is T_i=T[1+r(frac{gamma-1}{2})M²] where T is the temperature at that altitude, T_i is indicated total temperature, r is recovery factor, M is Mach number and γ is the ratio of specific heat at constant pressure to that of specific heat at constant volume.

6. What is the indicated temperature of an aircraft having mach number 2 and when temperature and recovery factor are 300K and 2?
a) 780K
b) 128K
c) 345K
d) 435K
Answer: a
Clarification: The answer is 780K. Given r=2, T=300K, M=2 and we know that γ for air is 1.4. From the formula T_i=T[1+r(frac{gamma-1}{2})M²].
On substituting the values we get T_i=300[1+2(frac{1.4-1}{2})2²]
On solving above equation we get T_i=780K.

7. What is the mach number of the aircraft which is moving in air at an indicated total temperature is 780K and the temperature, recovery factor at that point are 300K and 2?
a) 1
b) 2
c) 0.1
d) 0.2
Answer: b
Clarification: The answer is 2. Given r=2, T=300K, T_i=780K and we know γ of air is 1.4. From the formula T_i=T[1+r(frac{gamma-1}{2})M²].
On substituting the values in the formula, we get 780=300[1+2(frac{1.4-1}{2})M²].
On solving we get M=2.

8. The difference in indicated values and local values of altitude, airspeed and mach number is known as system pressure error.
a) True
b) False
Answer: a
Clarification: The difference in indicated values and local values of altitude, airspeed and mach number is known as system pressure error. The indicated values of the altitude, airspeed and mach number resulting from the measured values of the local or system, pressures will differ from the values that would occur when using the undisturbed freest stream pressures. This error is known as system pressure error.

9. Calculate the indicated temperature rise when indicated total temperature is 400K and temperature at that point is 389K.
a) 11
b) 5.5
c) 6
d) 12
Answer: a
Clarification: The answer is 11. Given T_i=400K and T=389K. The indicated temperature rise is measured by the formula, T_i-T.
On substituting the values we get the indicated temperature rise=400-389
The indicated temperature rise=11.

10. Calculate the ideal temperature rise when total temperature is 440K and temperature at that point is 369K.
a) 71
b) 70
c) 75
d) 78
Answer: a
Clarification: The answer is 71. Given T_t=440K and T=369K. The ideal temperature rise is measured by the formula, T_t-T.
On substituting the values we get the indicated temperature rise=440-369
The indicated temperature rise=71.

Aircraft Performance Multiple Choice Questions on “Cruise Method 2”.

1. Which factor must be reduced in constant angle of attack and constant altitude method?
a) Mach number
b) Angle of attack
c) Altitude
d) Temperature
Answer: a
Clarification: The factor that must be reduced in cruise method 2 (also known as constant angle of attack and constant altitude method) is mach number. Also the ratio of lift to drag and relative airspeed are kept constant i.e. L/D ratio and uare constant throughout the method.

2. Which of the following indicates the range formula in cruise method 2?
a) R=(frac{1}{C}big(frac{2}{rho SC_L}big)^{frac{1}{2}}int_{W_{i}}^{W_{f}}frac{dW}{W^{frac{1}{2}}})
b) R=(Big(frac{2}{rho SC_L}Big)^{frac{1}{2}}frac{L}{D}int_{W_{i}}^{W_{f}}frac{dW}{W^{frac{1}{2}}})
c) R=(Big(frac{2}{rho SC_L}Big)^{frac{1}{2}}frac{LC}{D}int_{W_{i}}^{W_{f}}frac{dW}{W^{frac{1}{2}}})
d) R=(frac{1}{C}Big(frac{2}{rho SC_L}Big)^{frac{1}{2}}frac{L}{D}int_{W_{i}}^{W_{f}}frac{dW}{W^{frac{1}{2}}})
Answer: d
Clarification: The correct range equation of cruise method 2 is given by R=(frac{1}{C}Big(frac{2}{rho SC_L}Big)^{frac{1}{2}}frac{L}{D}int_{W_{i}}^{W_{f}}frac{dW}{W^{frac{1}{2}}}) where R is range of the cruise, C is specific fuel consumption, S is span, ρ is density, C_L is coefficient of lift, L/D is lift to drag ratio, W_f and W_i are final and initial weights.

3. Which of the following is the correct integrated range equation of cruise method 2?
a) R=(frac{1}{C}Big(frac{2W_i}{S_{rho}}Big)^{frac{1}{2}}frac{C_L}{C_D}2Big(1-omega^{frac{-1}{2}}Big))
b) R=(Big(frac{2W_i}{S_{rho}}Big)^{frac{1}{2}}frac{C_{L}^{0.5}}{C_D}2Big(1-omega^{frac{-1}{2}}Big))
c) R=(frac{1}{C}Big(frac{2W_i}{S_{rho}}Big)^{frac{1}{2}}frac{C_{L}^{0.5}}{C_D}2Big(1-omega^{frac{-1}{2}}Big))
d) R=(frac{1}{C}Big(frac{2W_i}{S_{rho}}Big)^{frac{1}{2}}frac{C_{L}^{0.5}}{C_D}2Big(1-omegaBig))
Answer: c
Clarification: The correct equation of cruise method 2 is R=(frac{1}{C}Big(frac{2W_i}{S_{rho}}Big)^{frac{1}{2}}frac{C_{L}^{0.5}}{C_D}2Big(1-omega^{frac{-1}{2}}Big)) where R is range of the cruise, C is specific fuel consumption, S is span, ρ is density, C_L is coefficient of lift, C_l/C_d is ratio of coefficient of lift to drag, W_i is initial weight and ω is fuel ratio.

4. Cruise method 2 is also known as ____________
a) constant angle of attack and variable mach number
b) constant angle of attack and constant mach number
c) constant angle of attack and constant altitude number
d) constant mach number and constant altitude number
Answer: c
Clarification: Cruise method 2 also known as constant angle of attack and constant altitude method. In cruise method 2 altitude, the ratio of lift to drag and relative airspeed are kept constant i.e. L/D ratio and u and h are constant throughout the method.

5. Which of the following factors are not constant in cruise method 2?
a) altitude
b) relative airspeed
c) mach number
d) angle of attack
Answer: c
Clarification: Cruise method 2 also known as constant angle of attack and constant altitude method. In cruise method 2 altitude, the ratio of lift to drag and relative airspeed are kept constant i.e. L/D ratio and u and h are constant throughout the method.

6. The range factor of cruise method 2 is identical to that of cruise method 1.
a) True
b) False
Answer: a
Clarification: In cruise method 2 the range factor is given by R=(Big[frac{V_{mdi}}{C}E_{max}Big]Big{frac{2u^3}{u^4+1}Big}2Big(1-omega^{frac{-1}{2}}Big)) where (Big[frac{V_{mdi}}{C}E_{max}Big]) is range factor and is same of that in cruise method 1 but overall range of cruise method 2 is less than that of cruise method 1.

7. The endurance of cruise method 2 is identical to that of cruise method 1.
a) True
b) False
Answer: a
Clarification: The endurance of cruise method 2 is identical to that of cruise method 1. E=(Big[frac{E_{max}}{C}Big]Big{frac{2u^2}{u^4+1}Big}l_nomega) where V is true airspeed, C is specific fuel consumption, L is lift, D is drag, E_max is endurance, u is relative airspeed and ω is fuel ratio.

8. Which of the following is a reason of disadvantage of cruise method 2?
a) Increased mach number
b) Fuel saving
c) Increased time of flight
d) Increased weight of aircraft
Answer: c
Clarification: The disadvantage of cruise method 2 is that to compensate the weight of aircraft the mach number and relative airspeed are decreased and there is an increase in the time of flight thus does not making any fuel saving.

9. In which of the following cases cruise method 2 is used?
a) Commercial aircraft
b) Fighter aircraft
c) Military
d) Patrol and surveillance
Answer: d
Clarification: Cruise method 2 is used mainly for patrol and surveillance purposes as there is more endurance and time of flight and short range which is best suitable for the surveillance purpose.

10. In Cruise method 2 endurance is more concentrated than distance travelled.
a) True
b) False
Answer: a
Clarification: In cruise method 2 endurance is more concentrated than distance travelled. This is the reason which makes this cruise method 2 best suitable for patrol and surveillance purposes which mainly prefer more endurance and time of flight.