IFR Navaids - Radar & DME

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

• 7500 + MODE C

• 7600 + MODE C

• 7700 + MODE C

• 7007 + MODE C

Transponder Mode C is required to report aircraft altitude referenced to ______ and accurate within ______

• MSL 300ft

• MSL 200ft

• 1013.2 300ft

• 1013.2 200ft

What is the SSR code for an emergency?

• MODE A & 7700

• MODE A & 7600

• MODE A & 7500

• MODE A & 7000

When an altimeter is used in conjunction with an SSR transponder the digitised height signal is always referenced to:

• The altimeter sub-scale setting

• 1013.2 hPa

• QFE

• QNH

Which of the following is not true for secondary radar?

• The target must be active

• The return signal is not affected by the size, aspect or shape or material make-up of the target

• The target response can be coded to carry information as required

• The reflected signal varies according to the size of target

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 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 transceiver to a ground transceiver

• Generating an identical code internally and measuring the phase difference

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

The maximum theoretical range of a DME at 460 ft AMSL interrogated by an aircraft at FL 260 is:

• 228nm

• 183nm

• 190nm

• 137nm

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 sentence

• They are modulated differently

• The time delay between transmitted and received signals is incorrect