1. The use of autopilot for landing using ILS does not depend on _______
a) Visibility category
b) ILS ground installation standard
c) Runway lighting installation
d) Weight of the aircraft
Explanation: The height limits and visibility conditions in which the autopilot can be used to carry out a glide slope coupled approach to the runway depends on the visibility category to which the autopilot system is certified for operation, the ILS ground installation standard, the runway lighting installation and the airport’s runway traffic control capability.
2. Under what category does zero visibility conditions come?
a) Category I
b) Category II
c) Category III
d) Category IV
Explanation: Visibility conditions are divided into three categories, namely Category I, Category II and Category III, depending on the vertical visibility ceiling and the runway visual range (RVR). Category III includes zero visibility conditions.
3. What is DH?
a) Distance Height
b) Direct Height
c) Decision Height
d) Direction height
Explanation: This minimum permitted ceiling for vertical visibility for the landing to proceed is known as the decision height or DH. A very high integrity autopilot system is required for fully automatic landing below a DH of 100 ft – Cat. III conditions.
4. What is the frequency of marker beacon transmission?
a) 100 MHz
b) 75 MHz
c) 1 GHz
d) 1000 MHz
Explanation: The marker beacon transmissions are at 75 MHz. The middle marker beacon is located at a distance of between 1,000 and 2,000 m from the runway threshold and the outer marker beacon is situated at a distance of between 4,500 and 7,500 m from the middle marker.
5. MLS has a wide selection of channels to avoid interference with nearby airports
a) True
b) False
Explanation: Since microwaves are of higher frequency they can have a wide channel from 300 MHz to 300 GHz. This is particularly useful when two airports nearby are aligned equally. The MLS system an all weather guidance system with wide vertical and horizontal beam widths.
6. At what height is the auto flare initiated?
a) 100 ft
b) 50 ft
c) 25 ft
d) 10 ft
Explanation: The auto flare is initiated around 50 ft where the aircraft is over or very near the runway threshold so that the radio altimeter is measuring the height of the aircraft above the runway. Low range radio altimeters are used to ensure accuracy.
7. What type of controller is used in an auto flare control?
a) Proportional plus derivative
b) Proportional plus integral
c) Proportional plus integral plus derivative
d) Proportional only
Explanation: The auto-flare loop is a high-order system; apart from the lags present in the filtered rad.alt. signals there are also the lags present in the response of the pitch attitude command loop. This loop controls and its response is significantly slower at the low speeds during the approach. A proportional plus integral control term is used in the auto-flare controller to ensure accuracy and some phase advance is generally provided to compensate for the lags in the loop and hence improve the loop stability and damping.
8. What is the velocity at the start of flare maneuver if the approach speed is 130 knots?
a) 2.91 m/s
b) 3 m/s
c) 3.56 m/s
d) 10 m/s
Explanation: Vertical velocity at the start of flare = approach speed x glide slope angle. Thus Vv= 66.87* x sin(2.5°) = 2.91 m/s . *[converting knots to m/s].
9. What is the position accuracy that can be achieved by satellite guidance systems?
a) 10 m
b) 5 m
c) 0.5 m
d) 1 m
Explanation: The navigation position accuracy of 1 m which can be achieved with the differential GPS technique is being exploited in the US for landing guidance with a system called the Ground Based Augmentation System, GBAS. The Ground Based Augmentation System, when installed at an airport, will be able to provide the high integrity and accurate guidance necessary for landing in Cat. III visibility conditions.
10. What is the beam error in localizer for aircraft CG displacement of 5m at a range of 1,500m?
a) 0.0033 RAD
b) 3.3 RAD
c) 0 RAD
d) 5 RAD
Explanation: The beam error γ = d/R, where d is the displacement of the aircraft’s CG from the beam center line and R is the slant range of the aircraft. γ = 5/1,500 = 0.0033 RAD.