5. Radar & DME

If an aircraft is hijacked ICAO recommend which of the following SSR codes

• 7500

• 7600

• 7700

• 1200

Transponder Mode C is required to report aircraft altitude referenced to

• 1013.2

• MSL

• AGL

What is the SSR code for an emergency?

• 7700

• 7600

• 7500

• 1200

Which of the following statements is true?

• Primary radar gives range not bearing of a reflected object

• Secondary radar always measures the bearing of a reflecting object more accurately than primary radar

  Primary radar uses echoes

• Primary radar uses echoes from a reflecting object, whereas secondary radar uses the response from a transponder

• Only a secondary radar can be fitted to an aircraft

The essential difference between a primary radar and a secondary radar system is that

• A primary radar is ground based, whereas a secondary radar is an airborne system

• A primary radar is pulsed, whereas a secondary radar uses CW techniques

• A primary radar relies on target reflections, whereas a secondary radar relies on a transponder at the target to generate a reply pulse or pulses

• A primary radar is limited to line of sight, whereas a secondary radar is not

DME measures slant range and operates by

• A signal sent from the aircraft to a transponder on the ground

• A signal sent from the aircraft's transponder to a ground receiver

• Generating an identical code internally and measuring the phase difference

• Bouncing a radio wave off a prominent feature and timing the return

DME distinguishes between its signals returning from the ground equipment and signals reflected from the ground because

• They are at different frequencies

• They carry a unique coding sequence

• They are differently modulated

• The time delay between transmitted and received signals is incorrect

How many aircraft can a DME respond to simultaneously?

• 15

• 50

• 100

• 200

The OFF flag on aircraft DME mileage display indicates

• The DME is searching

• The DME is off

• DME is tuned to the wrong frequency

• All of the above

DME operates on

• VHF

• SHF

• UHF

• MF