Avionics - Introduction & Navigation Equations Quiz(MCQ)

1 .

What is the number of components of the vector that describes the translational motion of the vehicle?

A)

1

B)

2

C)

4

D)

6

Correct Answer : 6

Explanation : The three components of position and the three components of velocity make up a six component state vector that fully describes the translational motion of the vehicle.

2 .

What is the process called when the state vector is calculated on board the vehicle?

A)

Guidance

B)

Navigation

C)

Surveillance

D)

Position location

Correct Answer : Navigation

Explanation : When the state vector is measured and calculated on board, the process is called navigation. When it is calculated outside the vehicle, the process is called surveillance or position location.

3 .

Which type of navigation measure the state vector without regard to the path travelled by the vehicle in the past?

A)

AHRS

B)

Positioning

C)

Dead reckoning

D)

Direct reckoning

Correct Answer : Positioning

Explanation : Navigation systems can be categorized as positioning or dead reckoning. Positioning systems measure the state vector without regard to the path travelled by the vehicle in the past.

4 .

Which one of the following does not fall under the positioning system?

A)

AHRS

B)

Radio systems

C)

Celestial systems

D)

Mapping navigation systems

Correct Answer : AHRS

Explanation : There are three types of positioning systems radio systems, celestial systems and mapping navigation systems. AHRS or Attitude Heading Reference System use accelerometer and gyroscope and hence fall under the dead reckoning navigation system.

5 .

Which of the following navigational systems is most stealthy?

A)

VOR

B)

SONAR

C)

Celestial navigation

D)

Secondary surveillance radar

Correct Answer : Celestial navigation

Explanation : In celestial navigation, the position is computed by measuring the elevation and azimuth of celestial bodies relative to the navigational coordinate frame at precisely known times. Since it is a completely passive system, it is considered to be stealthy and is used in special purpose high altitude aircraft in conjunction with an inertial navigator.

6 .

How is the velocity of an aircraft measured by passive radio systems?

A)

Doppler shift

B)

Satellite mapping

C)

Secondary surveillance method

D)

Velocity data is transmitted by the aircraft and received by the station

Correct Answer : Doppler shift

Explanation : The aircraft’s velocity is measured from the Doppler shift of the transmission or from a sequence of position measurements. Since the aircraft is continuously moving, each interrogation pulse when it is received will have different phase shift which corresponds to the aircraft’s velocity.

7 .

Which of the following conditions does not lead to missed approaches?

A)

Traffic

B)

Excess fuel

C)

Poor visibility

D)

Alignment with runway

Correct Answer : Excess fuel

Explanation : A missed approach is initiated at the pilot’s option or at the traffic controller’s request, typically because of poor visibility, poor alignment with a runway, equipment failure, or conflicting traffic. A fuel dump is initiated when there is excess fuel in the aircraft.

8 .

What instrument is used to measure the aircraft’s altitude during the approach phase?

A)

Sound altimeter

B)

Infrared altimeter

C)

Pressure altimeter

D)

Radio altimeter

Correct Answer : Radio altimeter

Explanation : A radio altimeter can accurately measure the altitude of an aircraft and works on the radar principle. Typically, radio altimeters provide accurate altitude measurements till 5000ft and are used only during takeoff and landing.

9 .

The height at which approach is aborted when the runway is not in sight is called as?

A)

Landing altitude

B)

Clearance altitude

C)

Decision height

D)

Approach altitude

Correct Answer : Decision height

Explanation : Decision altitude is the altitude above the runway at which the approach must be aborted if the runway is not sight. Decision height published for each runway at each airport.

10 .

Departure and approach are subphases of what?

A)

Terminal phase

B)

Surface phase

C)

Takeoff phase

D)

Landing phase

Correct Answer : Terminal phase

Explanation : The terminal phase consists of the departure and the approach phase. Departure starts when the aircraft is in the ground and ends when it is out of the terminal area. The approach starts when the aircraft enters the terminal control area and ends when the aircraft intercepts the landing aids at approach fix.

11 .

What is the speed at which the takeoff is aborted when there is an engine failure?

A)

Takeoff speed

B)

Stall speed

C)

Decision speed

D)

Rotational speed

Correct Answer : Stall speed

Explanation : At any speed greater than the decision speed, takeoff is not aborted even when there is an engine failure. Stall speed is lower than the decision speed and hence the takeoff is aborted.

12 .

The distance the aircraft climbs to clear an obstacle of particular height during takeoff is called as?

A)

Ground roll

B)

Runway length

C)

Take off distance

D)

Airborne distance

Correct Answer : Airborne distance

Explanation : The extra distance the aircraft covers airborne but before it covers an obstacle of particular height is called airborne distance. Airborne distance is also added with the ground roll to give the total takeoff distance.

13 .

What is the takeoff clearance height for a military aircraft?

A)

20ft

B)

35ft

C)

50ft

D)

100ft

Correct Answer : 50ft

Explanation : The height that the aircraft must cover during the airborne distance is different for different aircraft depending upon their usage. The height of the obstacle is generally specified to be 50ft for military aircraft and 35ft for commercial aircraft.

14 .

The velocity at which yawing motion can be produced by rudder deflection while the aircraft is on the ground is called _______

A)

Control speed

B)

Ground roll speed

C)

Ground control speed

D)

Minimum control speed on the ground

Correct Answer : Minimum control speed on the ground

Explanation : Minimum control speed on the ground is the minimum speed at which enough aerodynamic force can be generated in the vertical fin by rudder deflection while the aircraft is still rolling on the ground to produce a yawing moment on the aircraft.

15 .

Which one of the following is not an input utilized by the aircraft navigation system?

A)

Sonar

B)

Radio aids

C)

Dead reckoning data

D)

Celestial measurements

Correct Answer : Sonar

Explanation : The navigation system utilizes three types of sensor information: position data from radio aids, radar and satellites; Dead reckoning data from inertial sensors; Line of sight direction to stars or celestial measurements.

16 .

What is the angle between the normal to the reference ellipsoid and the equatorial plane at a point called?

A)

Earth angle

B)

Geodetic latitude

C)

Geodetic angle

D)

Correction factor

Correct Answer : Geodetic latitude

Explanation : Geodetic latitude of a point is the angle between the normal to the reference ellipsoid and the equatorial plane. Geodetic latitude is our usual understanding of map latitude.

17 .

Which of the following is false with respect to Earth centered inertial coordinate system?

A)

Accuracy is 10-5/hr

B)

Newton’s laws are not valid

C)

Used in mechanizing inertial navigators

D)

Angular coordinates of stars are conventionally tabulated in ECI

Correct Answer : Newton’s laws are not valid

Explanation : The Earth centered coordinate system has three navigational functions. First, Newton’s laws are valid in any ECI coordinate frame, Second, the angular coordinates of stars are conventionally tabulated in ECI. Third, they are used in mechanizing inertial navigators.

18 .

Which coordinate system is used in satellite based radio navigation?

A)

Earth centered inertial

B)

Geodetic wander azimuth

C)

Earth centered, Earth fixed

D)

Geodetic spherical coordinates

Correct Answer : Earth centered, Earth fixed

Explanation : Satellite based radio navigation system uses ECEF coordinated to calculate satellite and aircraft position. The origin is at the mass center of the earth and its axis lies along the earth’s spin axis.

19 .

What is TDOP?

A)

Time Dilution of pressure

B)

Time Distortion of position

C)

Time Dilution of position

D)

Time Dilution of pseudorange

Correct Answer : Time Dilution of position

Explanation : TDOP is the Time Dilution of position. It is the contribution of clock error to the error in pseudorange.

20 .

A)

APEG

B)

GDCP

C)

GEOP

D)

GDOP

Correct Answer : GDOP

Explanation : GDOP or Geometric Dilution of Precision relates ranging errors to the dispersion in measured position. If three range measurements are made in the orthogonal direction, the standard deviation in the aircraft’s position error is the same as those of the three range sensors.

21 .

The angle of arrival, relative to the airframe, of a radio signal from an external transmitter is called _________

A)

Bearing

B)

Phase

C)

Heading

D)

Approach angle

Correct Answer : Bearing

Explanation : The angle of arrival, relative to the airframe, of a radio signal from an external transmitter is called bearing. Bearing is measured by the difference in phase or time of arrival at multiple antennas on the airframe.

22 .

What is the technique of calculating position from measurements of velocity called?

A)

Doppler radar

B)

Dead reckoning

C)

Celestial navigation

D)

Secondary surveillance

Correct Answer : Dead reckoning

Explanation : Dead reckoning is the technique of calculating position from the measurements of velocity. It is the means of navigation in the absence of position fixes and consists in calculating the position by extrapolating measured ground speed.