Which of the following cannot be used to obtain an approximate velocity?

A)
Primary radar
B)
GPS
C)
Doppler radar system
D)
Inertial navigation system

Correct Answer :   Primary radar


Explanation : Velocity from Doppler, inertial and GPS can be used as an approximation for velocity. It is possible for the radio controller on the ground to obtain the velocity of the rotorcraft but it is not possible for the pilot to get velocity data from primary radar.