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

Sound altimeter

Infrared altimeter

Pressure altimeter

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.

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

Doppler radar

Dead reckoning

Celestial navigation

Secondary surveillance

Correct Answer : Option (B) : 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.

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

Bearing

Phase

Heading

Approach angle

Correct Answer : Option (A) : 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.

________ related ranging errors to the dispersion in measured position?

APEG

GDCP

GEOP

GDOP

Correct Answer : Option (D) : 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.