Aircraft Maintenance Mcqs - Set 4

ANSWER: Roll, pitch and yaw

Explanation:
The three critical flight dynamics parameters are roll, pitch and yaw. They may also be referred to as the angles of rotation w.r.t. the aircraft’s three principal axes about its center of gravity.

ANSWER: A sideslip angle arises

Explanation:
When an aircraft yaws about its center of gravity, it creates a sideslip angle. It is the angle between the wheels of an aircraft and the direction in which the aircraft is travelling.

ANSWER: Reynolds Number

Explanation:
Viscosity of the flow is given by Reynolds Number. It is represented by Re. Mach number indicates the compressibility of flow and Knudsen number indicates rarefaction of the flow.

ANSWER: Absolute temperature

Explanation:
Absolute temperature is not an aerodynamic coefficient. However, pressure coefficient, lift coefficient and drag coefficient are all aerodynamic coefficients. A few other aerodynamic coefficients are lateral force coefficient and friction coefficient.

ANSWER: Measured in Hertz

Explanation:
Yaw rotation is the rotation of a body, which changes the direction in which it is pointing. It is an essential flight dynamic and is usually measured in degrees per second or radians per second.

ANSWER: False

Explanation:
Flight dynamics studies the stability and control of vehicles travelling through air. It does not study the efficiency of these vehicles; however, flight dynamics parameters are designed so as to improve the efficiency of these vehicles.

ANSWER: Zero bank angle

Explanation:
The equilibrium roll angle is known as zero bank angle; it may also be called wings level. The three critical flight dynamics refer to rotations about the respective axes starting from a defined equilibrium state.

ANSWER: Gravitational force

Explanation:
The most dominant force in spacecraft flight dynamics, is the gravitational force. This is because aerodynamic forces affecting the spacecraft in air, are very small, thereby making gravitational force dominant.

ANSWER: Centre of gravity

Explanation:
The control systems adjust the orientation of a vehicle about its centre of gravity. The control systems help rotate the aircraft in pitch, roll and yaw. It may be used to pitch the aircraft up or down.

ANSWER: True

Explanation:
Aircrafts increase or decrease the lift generated by the wings, by increasing or decreasing the angle of attack. Angle of attack is adjusted by changing the position of the nose of an aircraft.

ANSWER: Electromagnetic force

Explanation:
Spacecraft flight dynamics does not include electromagnetic force. However, propulsive force, lift and drag and gravitational force are all part of spacecraft flight dynamics. Propulsive forces are most dominant in rockets.

ANSWER: Angle of attack of the wing and the angle of attack of the vertical tail

Explanation:
The two major sources of change in the aerodynamic forces and moments applied to an aircraft are the angle of attack of the wing and the angle of attack of the vertical tail. The two angles are important to maintain the center of gravity of an aircraft.

ANSWER: Drag

Explanation:
The aircrafts are streamlined from nose to tail to reduce drag on the aircraft. Increased drag reduces the airspeed of an aircraft and hence increases flying time.

ANSWER: Sideslip angle

Explanation:
The angle of attack of the vertical tail is also known as Sideslip angle. It may also be referred to as beta. Similarly, the angle of attack of the wing is referred to as alpha.

ANSWER: Control systems

Explanation:
The actuator is a part of the control system in an aircraft. Basically, an actuator is a mover that requires a source of energy along with a control signal. The actuator works in such a way, that it converts the incoming signal’s energy into mechanical signals.

ANSWER: Slow the aircraft to a safe speed for landing

Explanation:
Drag is increased so as to slow the aircraft to a safe speed for landing. Drag offers negative impact to the airspeed thus slowing down the aircraft, thereby offering a safe landing.

ANSWER: Elevator

Explanation:
The elevator is a flight control surface controlling the pitch of an aircraft. It is also responsible for adjusting the angle of attack, and hence the lift of an aircraft. It is usually located at the ear of an aircraft.

ANSWER: Elevon

Explanation:
The combination of ailerons and elevators is called elevon. Their respective control inputs are also combined and it reduces the pilot’s workload. They are mostly used on tailless aircrafts.

ANSWER: Elevator

Explanation:
The edge flaps are a part of the wing assembly of an aircraft. They are used to increase the lift of an aircraft. Stabilizer, rudder and elevator are all situated at the rear of an aircraft and are a part of the tail assembly.

ANSWER: Rudder

Explanation:
The primary control of yaw is with the rudder. Yaw changes the direction in which the aircraft’s nose is pointing. In addition to the rudder, ailerons also have an effect on the yaw.

ANSWER: True

Explanation:
True, ailerons are used to steer the aircraft either left or right. They are mounted on the edge of each wing and work in opposite directions. Raising the aileron, reduces the lift on the wing and lowering the aileron, increases the lift.

ANSWER: Wing

Explanation:
Canard refers to a wing arrangement in aircrafts. In canard configuration, a small forewing is placed ahead of the main wing. The Wright Flyer of 1903 had a canard arrangement.

ANSWER: Unmanned aerial vehicles

Explanation:
UAVs refers to unmanned aerial vehicles. These are vehicles without a human pilot on board. Examples of UAVs are spaceships and drones. They are controlled using a ground based controller and a communication system.

ANSWER: Ailerons

Explanation:
The ailerons are part of the primary cockpit flight controls. The roll and pitch of the aircraft can be adjusted using the ailerons. Slats, spoilers and air brakes are part of the secondary flight controls.

ANSWER: True

Explanation:
True. Spoilers are used to reduce lift on an aircraft by hampering the flow of wind over its wings. They are used for reducing lift while landing an aircraft. They allow aircraft to lose altitude without gaining significant airspeed.

ANSWER: Perpendicular

Explanation:
An aircraft whose left wing is pointing straight down, will have its transverse axis perpendicular to the ground. Further, its vertical axis will be parallel w.r.t. the ground. These axes are relative to the earth and will change with the change in position of the aircraft.

ANSWER: Roll

Explanation:
The axis passing through the aircraft from nose to tail is called as longitudinal axis. Rotation about the longitudinal axis is called roll. Further, the angular displacement about it is called bank.

ANSWER: Empennage

Explanation:
The rudder is a part of the empennage. More specifically, it is mounted on the vertical stabilizer, at the rear end of the aircraft. If the pilot pushes the left pedal, rudder is deflected left and similarly when the pilot pushes the right pedal, rudder is deflected right.

ANSWER: Radars

Explanation:
Radars are not a part of flight control systems. However, ailerons, elevators and flaps are all part of the flight control systems. Some other flight control systems are elevens and flaperons.

ANSWER: Fly-by-wire

Explanation:
FBW refers to fly-by-wire. Fly-by-wire is a control system that replaces manual flight controls of an aircraft with an electronic interface. Flight controls are controlled through electronic signals, which are transmitted using wires.