Which mode is used for selective calling?

Mode S

Mode C

Mode B

Mode A

Correct Answer : Mode S

Explanation : Different modes have its own unique features; mode A gives only identity, mode c gives identity and altitude, mode B is used in European operations and mode S is used for selective calling of transponders.

Recently Updated in Avionics Questions

What is the range of typical weather radar?

5 nmi

50 nmi

200 nmi

500 nmi

Correct Answer : Option (C) : 200 nmi

Explanation : The use of airborne weather radar is one method of storm avoidance. A weather radar system can show centers at a distance of up to 200 nmi.

What is the frequency of operation of weather radar?

500 kHz

548 kHz

1000 MHz

9375 MHz

Correct Answer : Option (D) : 9375 MHz

Explanation : The weather radar operates at a frequency of 9375 MHz, corresponding to a wavelength of 3 cm. This small wavelength gets easily reflected from clouds containing high water concentrations.

What is the gain required by a weather radar antenna?

5 dB

25 dB

50 dB

65 dB

Correct Answer : Option (B) : 25 dB

Explanation : The signal strength of echoes from storms located at a distance from the aircraft is very low, which requires the transmitter to operate at very high power levels and that the antenna have a gain of more than 25 dB.