# Aircraft Design Questions and Answers – Flight Mechanics – Landing Analysis

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This set of Aircraft Design Multiple Choice Questions & Answers (MCQs) focuses on “Flight Mechanics – Landing Analysis”.

1. Following diagram represents ____________ a) typical landing analysis segments
b) takeoff phase
c) climbing
d) takeoff ground roll

Explanation: Above diagram is showing typical landing phase of an aircraft. As shown in the diagram landing phase is subdivided into number of segments such as flare distance, Approach distance etc. Takeoff ground roll is a segment of takeoff phase. Takeoff phase includes ground roll, transition, climb etc.

2. The segment marked by ‘?’ in following diagram is showing _____ a) approach
b) climb
c) takeoff
d) cruise

Explanation: The term marked by? Is showing the Approach segment of aircraft landing phase. Climbing phase is used to increase the altitude of the aircraft. Cruise segment has lift equal to weight and Thrust equal to drag. Takeoff phase is different from the landing phase.

3. The distance shown by ‘?’ in the following diagram is termed as __________ a) flare distance
b) loiter
c) cruise
d) climb

Explanation: Above diagram is illustrating typical landing phase of the aircraft. As shown in the diagram flare distance is marked by ‘?’. Aircraft will decelerate from Approach speed to touchdown speed during flare.

4. Find the approach speed if, stall speed is 12 unit.
a) 15.6 unit
b) 12 unit
c) 10 unit
d) 1 unit

Explanation: Approach speed = 1.3* stall speed = 1.3*12 = 15.6 unit.

5. Find the approach speed for military aircraft. Considered stall speed is 22unit.
a) 26.4 unit
b) 20 m
c) 12 ft
d) 45 unit

Explanation: For military aircraft, Approach speed = 1.2*stall speed = 1.2*22 = 26.4 unit.

6. Find the required amount of touchdown speed if stall speed is 100knots.
a) 115 knot
b) 120 knot
c) 100 knot
d) 99.2 knot

Explanation: Touchdown speed = 1.15*stall speed = 1.15*100 = 115 knot.

7. If stall speed is 120 knots then, find average velocity at flare.
a) 147.6
b) 120
c) 110
d) 567

Explanation: Average velocity at Flare = 1.23*stall speed = 1.23*120 = 147.6 knots.

8. For military aircraft touchdown speed is 100 knots then, approximate value of stall speed.
a) 90.90
b) 100
c) 200
d) 223

Explanation: Stall speed = touchdown speed/1.1 = 100/1.1 = 90.90.

9. Find the required average velocity during flare for military aircraft if stall speed is 45 unit.
a) 51.75 unit
b) 60 unit
c) 45 unit
d) 100 unit

Explanation: Average velocity during flare = 1.15*stall speed = 1.15*45 = 51.75 unit.

10. Determine the value of FAR field length. Consider approach of 100 ft., flare of 120 feet and ground roll of 600ft.
a) 1366.12
b) 109
c) 600
d) 700

Explanation: FAR field length = 1.666*(approach + flare + ground roll)
= 1.666*(100 + 120 + 600) = 1366.12.

11. Which of the following is correct?
a) Aircraft decelerates from Approach to Touchdown speed during flare
b) Lift is always same as weight
c) Drag is always same as Thrust
d) Thrust loading is defined as the ratio of lift to drag

Explanation: During flare aircraft will decelerates from Approach speed to touchdown speed. Lift is not always same as weight. Drag is not always same as Thrust. During cruise, lift is equal to weight and Thrust is equal to drag.

12. Final velocity at the end of the landing phase will be ____________
a) zero
b) same as Approach speed
c) touchdown speed
d) same as climb rate

Explanation: Final velocity at the end of the aircraft landing phase will be zero. It is not equal to approach speed. Touchdown speed is achieved during flare segment. Rate of climb is vertical velocity of the aircraft.

Sanfoundry Global Education & Learning Series – Aircraft Design. 