This set of Aircraft Maintenance Multiple Choice Questions & Answers (MCQs) focuses on “Aviation Communication Systems – VOR-1”.
1. What is the full form of VOR?
a) Virtual Omni-Directional Range
b) VHF Omni-Directional Range
c) VHF Omni-Directing Range
d) VHF Omni-Directional Radar
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.
2. VOR is a _________ range radio navigation method.
b) Ultra long
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.
3. The line of position is called the ________ from the VOR.
Explanation: 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.
4. The VOR uses frequencies in which of the following band?
Explanation: 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.
5. What is the full form of RDF?
a) Radial direction finding
b) Radio direction finding
c) Rate direction finding
d) Ratio 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.
6. Where was the VOR developed?
d) The United States
Explanation: 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.
7. The extremely directional second signal sent by a VOR ground station generally rotates in a clockwise direction in space for about ________ times a second.
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.
8. The signals transmitted from VOR stations are competent up to __________
a) 4,000 miles
b) 2,000 miles
c) 200 miles
d) 10,000 miles
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.
9. VOR and NDB approaches are being replaced by _________
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.
10. VOR signals provide much greater accuracy as compared to NDB systems.
Explanation: True, VOR signals provide much greater accuracy as compared to NDB systems. These systems also offer better reliability in comparison to NDB systems, due to a number of factors affecting the systems performance.
11. How much is the predictable accuracy of VOR signals?
a) 900 km
b) 90 km
c) 90 m
d) 900 m
Explanation: 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.
12. VOR stations depend on __________
a) Line of approach
b) Line of sight
c) Line of descent
d) Line of attack
Explanation: 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.
13. VHF radio is more vulnerable to diffraction.
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.
Sanfoundry Global Education & Learning Series – Aircraft Maintenance.
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