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1.6
1.6.1
1.6.1.1
Aircraft information
General
The factual information regarding the history of the aircraft, its engines, equipment and instrumentation remained valid as contained in section 1.6 of the 1983 ICAO report.
1.6.1.2
The aircraft was equipped with the following instruments and equipment relevant to some degree to the investigation: three VHF transceivers, two HF transceivers, two SSR transponders, one Selcal, two weather radars, three INS, two ADF receivers, two VOR/ILS receivers, one marker beacon receiver, two DME, two compass systems, two autopilots, one auto-throttle, two horizontal situation indicators (HSI), two attitude director indicators (ADI), four radio magnetic indicators (RMI), one DFDR and one CVR.
1.6.1.3
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The aircraft communication radio aerials were positioned as follows: HF 1 left wing tip. HF 2 right wing tip, VHF 1 above upper deck fuselage area, VHF 2 - under central fuselage, and VHF 3 - on top of rear fuselage.
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1.6.2
Aircraft flight log
1.6.2.1
discrepancies:
1.6.2.2
During the flight from New York to Anchorage the flight crew recorded the following
heading flag was in view on co-pilot's HSI. The central instrument warning system (CIWS) light was flashing but went out with compass transfer switch
VHF 2 was noisy
map table spring was damaged.
The aircraft was dispatched from Anchorage in accordance with the Minimum Equipment List with the defect in the No. 2 compass system deferred. The VHF 2 was ground checked and found to operate normally. Repair of the map table spring was deferred for rectification in Seoul.
1.6.3
1.6.3.1
Inertial navigation system
The aircraft was equipped with three Litton LTN-72R-28 INS units. The INS was not modified for radio updating.
1.6.3.2
Each INS consisted of three units. The mode selector unit (MSU) was used to control the operating modes of the system. The control display unit (CDU) was used to enter and display navigation data. Both units were located on the flight deck. The inertial navigation units (INU) contained the inertial sensors plus a computer to perform the navigational computations. The INUS were located in the aircraft electronics bay with a battery for each as a backup source of power.
1.6.3.3
The INS allowed the pilot to, inter alia, store flight plans of up to nine waypoints, display navigational data, and provide steering commands to the autopilot for automatic flight control.