TNAG-2856-FCO40-4109-Hong-Kong-compensation-claim-regarding-Korean-Air-Lines-Flig-1993 — Page 102

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1.14.3.7.2 The basic parameters of coarse altitude, calibrated airspeed and magnetic heading for these four flights recorded on the DFDR were consistent with the known details of the flights.

1.14.3.8

Validation of the data recovered from the DFDR

1.14.3.8.1

The DFDR record showed that the magnetic heading was constant throughout most of the last flight. The recorded headings were plotted on a sensitive scale on which the resolution of the measurements was clearly evident. This showed that the recorded headings were predominantly 245.4° with variations from 244.9° to 246.0°. The validity of the heading indication was confirmed by the record of the associated roll attitudes of the aircraft. The variations in roll attitude were minimal and were themselves supported by the lack of any significant control wheel movement.

1.14.3.8.2 The magnetic heading was studied for validation at appropriate stages in the recording of the previous flights. Also, the recorded magnetic headings during take-offs and landings were compared with runway directions and were found to be within acceptable tolerances.

1.14.3.9

The take-off and cruise phases

1.14.3.9.1 The DFDR record confirmed that KE 007 turned on to runway 32 at Anchorage and immediately commenced its take-off run. About 23 seconds after lift-off, a turn to the left was initiated onto a magnetic heading of about 220° which was reached approximately 110 seconds after lift-off. Autopilot A was selected to Command mode 130 seconds after lift-off. The aircraft then executed a turn. with up to 17° of bank angle on to the magnetic heading of approximately 245° which it reached about 180 seconds after lift-off and then maintained until the attack. Autopilot A remained in Command mode until the attack phase.

1.14.3.9.2

The aircraft reached FL 310 thirty minutes after take-off, and remained at that level for the next two hours thirty-seven minutes. It then climbed to FL 330, maintaining that level for two hours ten minutes and then ascended to FL 350. The attack occurred only three minutes after reaching that level. These changes in flight level matched the ATC clearances.

1.14.3.9.3 A list of 191 radio transmissions from KE 007 recorded on the DFDR during the last flight was compiled. The time and duration of each transmission were noted together with which radio. was used. The DFDR information was studied in detail to eliminate any false indications of transmitter keying due to synchronization losses in the recovered serial digital data.