Билет №37

1). Instrument Landing System is a runway approach aid providing lateral and vertical guidance that allows aircraft to safely approach the runway from several miles out.

2). ILS Airborne Equipment - ILS equipment in the aircraft consists of a receiver with localizer, glideslope and marker beacon facilities, three aerials, a control unit, and an indicator displaying localizer and glideslope deviation and set of marker beacon lights. The control unit normally always either ILS or VOR frequency to be selected. Selection of the VHF localizer frequency automatically selects the paired UHF glideslope frequency.

3). At what Frequency operate Radio Telefone. Airband radiotelephones used for air to ground communication between pilots and controllers operates in the VHF band from 118.0 to 136.975 MHz, using amplitude modulation.

Билет №38

1). Marker Beacons - all marker beacons transmit on a radio frequency of 75 MHz. The energy pattern is fan shaped and mainly vertical with the result that there is very litter chance of interference. By comparing the pressure or radio altimeter readings with the published height of the glide slope at the markers, it is possible to check the proper functioning of the ILS. Passage over the markers also allows range from touch-down to be checked. Outer, middle and inner markers transmit on the same radio frequency but with different rates of amplitude modulation. The modulated signal contains Morse-type dots and dashes and activates the blue, amber or white lights which flash in synchronism with the dots and dashes.

2). Flag Alarms - will appear and the needles will centralize when:

• The aircraft is outside of the ILS service area.

• There is a significant fault in the transmission, e.g. modulation not deleted.

• The ground or airborne equipment is switched off.

3). At what Frequency operate MLS. The operating frequencies for MLS lie in a portion of the C-band (5030–5091 MHz) designated for use in aeronautical telecommunications. This frequency choice allows a 12-ft (3.6-m) antenna to generate the 1° beam width pattern needed to exclude most reflections.

Билет №39

1). What does MLS offer.

• Multiple approach paths to the same runway - horizontally.

• Large numbers of channels.

• Curved and zigzag as well as straight in approaches.

• Improved range information.

• Automatic data transfer (ground-to-air).

2). Describe the term Multiple Approach Paths .

Whereas ILS is limited to a single localizer centre line, MLS can provide approach paths which vary 60° or more from the direction of the associated runway. This permits greater flexibility for ATC by allowing aircraft to make simultaneous approaches along different paths. Aircraft can approach in alternating fashion from either side of the extended runway centre line. It is possible for MLS to vector aircraft to multiple runways using a single MLS transmitter site.

3). At what Frequency operate VOR. Beacon VOR radiates at one of 160 carrier frequencies (ranging from 108 to 117.975MGts 50kHz steps) and the reference signals are variable frequency 30Hz phases.