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The CORRECT answer is (a) DISTANCE measuring equipment

To explain: DME REFERS to distance measuring equipment. It is a radio navigation TECHNOLOGY that measures the distance between an aircraft and a ground station.

Right choice is (b) 960 MHz and 1215 MHz

The BEST I can explain: The PROPAGATION delay of DME radio signals in the frequency band is TIMED between 960 MHz and 1215 MHz. Line of visibility between the aircraft and the ground station is necessary.

Right option is (C) Channel ASSIGNMENT

The explanation: The channel assignment SPECIFIES the carrier frequency and the spacing between the pulses. These are two essential OPERATING VALUES of the DME.

The CORRECT choice is (d) Rolls-Royce

Easiest explanation: Rolls-Royce is not an AGENCY that sets STANDARDS for DME systems. However, RTCA, EASA and ICAO are all agencies that set standards for DME systems.

Right answer is (B) ULTRA high frequency

The explanation: ICAO CHARACTERIZES DME TRANSMISSIONS as UHF or ultra high frequency. This is because of the relatively high frequency of such transmissions in comparison to other transmissions. It may also be described by the term L-band.

Correct OPTION is (a) Australia

To explain I WOULD say: The DME instrument was developed in Australia. It was invented by James Gerrand, under the supervision of Edward George Bowen. Germany is another country having significant contributions to the aerospace industry. Airbus has a major facility at Hamburg, Germany. INDIA and Canada also have a FAIR share of Aerospace Business.

Right OPTION is (a) TACAN

For explanation I would say: The DME is FUNCTIONALLY IDENTICAL to the distance measuring COMPONENT of TACAN. This is done to MAINTAIN compatibility between the two systems.

The correct answer is (a) 50 MICROSECONDS

Easy explanation: 50 microseconds is the typical time delay after which the aircraft interrogates with the ground TRANSPONDER. The process involves a SERIES of pulse-pairs (INTERROGATIONS).

The CORRECT answer is (c) 1 kW

Easy explanation: The typical PEAK pulse output of a DME ground transponder for en-route or terminal navigation is 1 kW, on the assigned UHF channel.

The correct choice is (b) TRUE

Easiest explanation: True, The DME system comprises a UHF interrogator in the aircraft. This interrogator may also be referred to as a receiver or transmitter and is NECESSARY to interpret the incoming UHF transmission signals.

Correct CHOICE is (c) 12.36 MICROSECONDS

The explanation is: 12.36 microseconds is the TIME taken by a radio signal to travel 1 nautical MILE to the target and back. The distance is approximately 1,852 meters.

Correct CHOICE is (b) 185 m

Explanation: 185 m is the ACCURACY of DME ground stations. It may VARY by ±0.1 nautical mile. ICAO recommends an accuracy of less than the SUM of 0.25 nautical miles.

Correct answer is (d) 1.0 nautical mile

To explain: An AIRCRAFT directly above the DME station at 1 nautical mile altitude WOULD SHOW, 1.0 nautical mile on the DME readout. This indicates the aircraft is technically a mile away, just a mile straight up.

Right option is (a) SLANT range

Easy EXPLANATION: The physical distance between the AIRCRAFT antenna and the DME transponder antenna is referred to as slant range. It is measured USING the DME.

Right choice is (a) 2700

For explanation: The typical DME GROUND BASED responder beacon has a limit of 2700 interrogations per second. It refers to pulse PAIRS per second, CALLED PPS.

Correct option is (a) FALSE

Easy EXPLANATION: False, the spacing of all CHANNELS is 1 MHZ. Further, it has a signal SPECTRUM width of 100 kHz. There are 126 channels each, for interrogation and reply.

Correct CHOICE is (c) 1025 MHz to 1150 MHz

To elaborate: 1025 MHz to 1150 MHz are the frequencies are USED by an AIRPLANE’s DME interrogator. DME frequencies are paired to VHF OMNIDIRECTIONAL range frequencies.

The CORRECT choice is (d) 962 MHZ to 1213 MHz

For explanation: 962 MHz to 1213 MHz is the RANGE of frequency for the transmitting channel of DME transponders. The range frequency for the RECEIVING channel is between 1025 and 1150 MHz.

Correct option is (b) 1,350 Hz

Explanation: The DME USE a 1,350 Hz MORSE code in order to identify themselves. This code is in the form of a three LETTER identity, which when COLLATED with either a VOR or ILS system, will have a similar identity code.

The correct ANSWER is (a) 12,000 FEET

Easy EXPLANATION: Terminal transponders generally WORK to a minimum height above ground of 12,000 feet. These transponders are usually installed in airport buildings. Such transponders often have a short range and are unable to work in EXTREME weather conditions.

Right answer is (d) 130 nautical miles

Best explanation: The RANGE of high altitude TRANSPONDERS is 130 nautical miles. They typically provide service to a minimum height of 45,000 feet. These DEVICES are based on wireless COMMUNICATION and can operate in extreme conditions.

Correct answer is (b) True

Explanation: True, the X channels have both INTERROGATION and reply pulse PAIRS SPACED by 12 microseconds. This separation is not the same for Y channels.

Right ANSWER is (C) 36 MICROSECONDS

Explanation: The Y CHANNELS interrogation pulse pairs are SPACED by 36 microseconds. However, the Y channel reply pulse pairs are spaced by 30 microseconds.

Correct option is (b) VHF Omni-Directional Range

The explanation: The term VOR REFERS to VHF Omni-Directional Range. Further, the term VHF is an acronym for Very HIGH Frequency. This is a SYSTEM used in aircrafts for navigation purposes and requires very high frequency transmission signals.

The correct option is (a) Short

Explanation: The VOR transmission is a short RANGE RADIO navigation METHOD. These systems allow an aircraft to determine its POSITION during flying phases and help it align with the DESIRED flight path.

The correct ANSWER is (c) RADIAL

To explain: The line of position is CALLED the radial from the VOR. The position of an aircraft can be fixed using the intersection of radials from two DIFFERENT VOR stations.

The CORRECT answer is (c) VHF

For EXPLANATION I WOULD say: The VOR uses frequencies in the VHF band, i.e. very high frequency band. The LETTER V in VOR stands for VHF. The system is used by both commercial and general aviation.

The CORRECT option is (a) 30

Explanation: The extremely directional second signal SENT by a VOR ground station, generally rotates in a clockwise direction in space for about 30 times a second. In ORDER to PROPAGATE such signals, phased antenna arrays have to be used.

Correct option is (b) Radio direction finding

Explanation: The term RDF in aviation terminology refers to radio direction finding. The system is USED in order to DETERMINE the direction from which the received SIGNAL was originally transmitted.

The CORRECT choice is (d) The UNITED States

The BEST I can explain: The VOR was developed in the United States. It was developed in the beginning of 1937 and was deployed by 1946. In 2000, there were about 3,000 VOR stations OPERATING around the world.

Correct option is (c) 200 MILES

The EXPLANATION: The signals TRANSMITTED from VOR stations are competent up to 200 miles. The transmitted signals act as a line of sight in between the RECEIVER and the transmitter.

The correct option is (b) RNAV

Easy explanation: Newer RNAV approach procedures are replacing the older VOR and NDB approaches. These newer systems are HOWEVER expensive and involve HIGH MAINTENANCE costs. They may also be REFERRED to as GPS.

Right answer is (c) 90 m

The explanation is: The predictable accuracy of VOR SIGNALS is 90 m, which is approximately 300 FEET. The accuracy can also be described as 2 sigma at 2 NM from a PAIR of VOR BEACONS.

Right answer is (b) Line of sight

To elaborate: VOR stations are dependent on line of sight. They HEAVILY rely on it as an unclear line of sight means the observer will not be ABLE to see the TRANSMITTING ANTENNA clearly and thus an appropriate signal will not be received.

The correct choice is (a) False

Easiest explanation: False, radio devices based on VHF transmission are less VULNERABLE to diffraction. This is DUE to the FACT that VOR bearing is not affected by winds. It is also not affected by the RELATIVE ORIENTATION of the aircraft at a particular instant.

The correct choice is (b) True

To explain I WOULD SAY: True, the channels 108.10, 108.15, 108.30, 108.35 and so on, are RESERVED for ILS in the US.

Right answer is (d) 108.0 MHZ and 117.95 MHz

To explain: The VORs are assigned RADIO CHANNELS between 108.0 MHz and 117.95 MHz. VOR range is limited to the HORIZON, or closer if mountains intervene.

Right OPTION is (a) 50 kHz

To EXPLAIN I would say: The spacing between VOR channels is 50 kHz. The frequencies lie in the very high frequency (VHF) range and VOR STATIONS rely on line of sight. Further, to leave channels for ILS, in the range 108.0 to 111.95 MHz, the 100 kHz DIGIT is always even.

Correct choice is (d) 9,960 Hz

Easiest EXPLANATION: The conventional 30 Hz REFERENCE signal is frequency modulated on a 9,960 Hz SUB carrier.The omnidirectional signal usually CONTAINS an AMPLITUDE modulated voice channel.

The correct option is (b) Omni BEARING indicator

The explanation: A typical light-airplane VOR indicator may also be CALLED Omni bearing indicator, or OBI. It consists of a knob to rotate an Omni Bearing Selector, referred to as OBS. This OBS is used to set the desired COURSE.

The CORRECT choice is (a) Horizontal SITUATION indicator

Easiest explanation: HSI refers to Horizontal situation indicator. It is a FLIGHT instrument that combines VOR-ILS DISPLAY, thus reducing the pilot’s workload.

The CORRECT answer is (a) Jet Routes

For EXPLANATION I WOULD say: In the United States, the upper air routes are referred to as jet routes. Further, the routes are named as such as most countries around the WORLD, use SEPARATE systems of airway at different levels.

Correct answer is (d) VORTAC

For explanation I WOULD say: VOR and TACAN beacons that are collocated together are REFERRED to as VORTAC. A VOR equipment collocated solely with a DME equipment is referred to as a VOR-DME. All these are radio BASED navigational aids for PILOTS.

Right option is (b) True

Explanation: True, all the radio NAVIGATION beacons monitor their own OUTPUT. This is a necessary requirement for such beacons because they use REDUNDANT systems and thus failure of one system will lead to a change over to the AVAILABLE standby systems.

The correct answer is (c) Temperature

Explanation: Temperature is not a parameter monitored by the VOR BEACONS. However, bearing accuracy, signal level, presence of notches ALONG with the REFERENCE and variable signal modulation indices are the FIVE parameters monitored by the VOR beacons.