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1.14.1.3
A comprehensive assessment of the physical characteristics of the tapes and the information recorded was made to ensure that they contained authentic records from the CVR and the DFDR installed on KE 007.
1.14.2
Cockpit voice recorder
1.14.2.1
CVR design and installation
1.14.2.1.1
KE 007 was equipped with a Collins 642C-1 CVR, part number 522-4057-002 and serial number 1397. The CVR was designed to record four channels of information on a continuous loop of tape that was 0.25 inches wide and approximately 215 ft in length. The tape was driven at 1.33 inches/second by a synchronous motor that rotated at a speed dictated by the frequency of the aircraft's 400 Hz AC power supply. The CVR was required to retain a minimum of the last thirty minutes of recorded information.
1.14.2.1.2 The CVR had a light-weight outer case into which was slid a chassis containing the tape transport which was housed in an armoured and heat-insulated container. Forward and aft of the container were the associated connectors, power supply and electronic circuits. The armoured container was designed to protect the tape from exposure to fires and high speed impacts.
1.14.2.1.3 The CVR was installed adjacent to the DFDR in the Aft Equipment Centre located in the pressure cabin aft of the left rear passenger door and above the level of the top of the door.
1.14.2.1.4
The 400 Hz power supply to the CVR was fed from the circuit breaker panels near the Flight Engineer's station on the flight deck, in a raceway along the upper right side of the main passenger cabin to a point opposite the CVR and then across the top of the cabin to the CVR. The CVR signals were fed in a raceway along the upper left side of the fuselage.
1.14.2.1.5 The information recorded on the individual crew member's audio channels depended on the selections each had made on his audio selector panel. This could have included any combination of incoming information from the three VHF and two HF radios together with intercom and public address messages. Audio through hand, boom or oxygen mask microphones of the crew member concerned were also recorded.
1.14.2.2
Inspection of the CVR components
1.14.2.2.1 Examination of the tape transport identified it as being from a Collins 642C-1 CVR. The unit had suffered structural and corrosion damage and components inside had been dismantled. The corrosion was similar to that seen on other recorders that had been immersed in sea water.
1.14.2.2.2 The armoured container had suffered a severe blow on the front side, which had deformed it inwards. Marks in one corner of the box that formed the inner layer of the armoured container were consistent with damage to the turntable and its metal cover which indicated that those items had become detached from their mountings. Also, the side of the container had been subjected to a large distributed force, such as a high speed water impact.