TNAG-2856-FCO40-4109-Hong-Kong-compensation-claim-regarding-Korean-Air-Lines-Flig-1993 — Page 80

1.6.4

Weather radar

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1.6.4.1

The aircraft was equipped with two Bendix RDR-IF weather radar sets and the associated wave guide and aerial system. This radar had a maximum range of 200 NM with a 180° scan capability.

1.7

Meteorological information

1.7.1

Weather over the North Pacific

1.7.1.1

There was extensive coverage of low, medium and high level clouds over southern Kamchatka associated with an active cold front. Over the Sea of Okhotsk the cloud decreased to scattered low clouds in a ridge of high pressure lying roughly northwest to southeast across R20. Cloud coverage increased again approaching southern Sakhalin to a condition of mostly overcast low cloud with scattered medium and high clouds, the latter in streaks, due to the approach of a warm front located at 18:00 hours over the extreme south of Sakhalin Island.

1.7.2

1.7.2.1

Light conditions

The moon was in the last quarter with approximately 45 per cent of the disc illuminated. At 18:00 hours the moon was about 60° above the horizon. The sun rose at 20:13 hours on 31 August in the area of interception. At 18:30 hours at FL 350 night time darkness still prevailed.

1.7.3

1.7.3.1

Winds

The estimation of the wind field along the track of KE 007 was based on the final analysis for the 250 hPa pressure level valid for 18:00 hours 31 August 1983 obtained from the Canadian Meteorological Centre, the 250 hPa wind forecast valid at 18:00 hours 31 August 1983, routine air- reports given by KE 007, data provided by the Russian Federation and routine air-reports made by KE 015 east of 180 W.

1.7.3.2

The winds were generally westerly (260-290°) and the wind speeds were between 30 and 50 kt with local maxima (50-55 kt) between 170-175 W, and 155-145 E, respectively. In addition, an area of very weak winds was experienced between 150-145 E over the Sea of Okhotsk. The presence of this minimum was evident from KE 007's exchange of wind information with KE 015 as recorded on the CVR at 18:05 hours; KE 007 reported 215/15 kt. The weak wind fitted well with the final analysis for 250 hPa for 18:00 hours 31 August 1983.

1.7.3.3

The wind field indicated that the jet stream was well south of the track of KE 007. Under these circumstances, the presence of any significant turbulence was unlikely.

1.8

1.8.1

Aids to navigation

The en-route ground based aeronautical aids to navigation available on the assigned route were the following:

a) Anchorage airport surveillance radar (ASR), with a coverage of 60 NM and

completely overlapped by the Kenai radar;