This set of Aircraft Maintenance Multiple Choice Questions & Answers (MCQs) focuses on “Aviation Communication Systems – ILS-1”.
1. What is the full form of ILS?
a) Inclined Landing System
b) Incident Landing System
c) Instrument Landing System
d) Immediate Landing System
Explanation: ILS refers to Instrument Landing System. It is an aircraft system that enables pilots to take an instrument approach to landing if they are unable to establish visual contact with the runway.
2. ILS operates as a __________ based instrument approach system.
Explanation: ILS operates as a ground based instrument approach system. It provides the aircraft with horizontal and vertical guidance just before and during landing.
3. The localizer provides _________ guidance.
Explanation: The instrument landing system of an aircraft involves two independent sub systems. The two systems are the localizer and the glide slope. The former provides lateral guidance whereas the later provides vertical guidance.
4. A localizer is generally located beyond which end of a runway?
Explanation: The localizer system is generally located beyond the departure end of a runway. The system comprises a number of pairs of directional antennas.
5. What of the following is the lateral component of the ILS?
a) Glide slope
d) Gyro compass
Explanation: Localizer is the lateral component of the ILS. Whereas, glide slope is the vertical component. The localizer works like cooperation between the transmitting airport runway and the receiving cockpit instruments.
6. The LOC signal is in the __________ range.
a) 11 Hz
b) 11 MHz
c) 110 Hz
d) 110 MHz
Explanation: The LOC signal is in the 110 MHz range. Similarly, G/S signal is in the 330 MHz range. Localizer and glide slop carrier frequencies are paired with each other.
7. What is the frequency range for LOC carrier frequencies?
a) 108.10 MHz to 111.95 MHz
b) 108.10 Hz to 111.95 Hz
c) 10.10 Hz to 11.95 MHz
d) 10.10 MHz to 11.95 MHz
Explanation: The frequency range for LOC carrier frequencies is 108.10 MHz to 111.95 MHz. Each antenna transmits a narrow beam, for the LOC.
8. ILS beams intended for use in one direction only are called __________
a) Single beam
b) Forward beam
c) Back beam
d) Double beam
Explanation: ILS beams intended for use in one direction only are called back beams. These beams are of help during the approach, but the use of back beam localizer reduces precision compared to normal use.
9. The center of the glide slope signal is arranged so as to define a glide path of roughly __________ degrees above the horizontal reference.
Explanation: The center of the glide slope signal is arranged so as to define a glide path of roughly 3 degrees above the horizontal reference. A carrier signal is used to transmit the glide slope signal.
10. The pilot controls the aircraft such that the glide slope indicator remains in the center of the display.
Explanation: True, the pilot controls the aircraft such that the glide slope indicator remains in the center of the display. This is to ensure that the aircraft is following the glide path and it reaches the runway at the proper touchdown point.
Sanfoundry Global Education & Learning Series – Aircraft Maintenance.
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