ALTITUDE WAS DUE TO A DECISION TAKEN BY THE PILOT RATHER THAN A VIOLENT GUST OF WIND . IN VIEW OF THOSE CIRCUMSTANCES THE DEFENDANT HAS ACCEPTED THAT THE LOSS OF ALTITUDE MIGHT HAVE BEEN CAUSED BY THE VERY STRONG TURBULENCE THROUGH WHICH THE AIRCRAFT WAS FLYING .
12 HOWEVER , AFTER THE WITNESSES AND TECHNICAL EXPERTS HAD BEEN EXAMINED THE DEFENDANT CONTINUED TO MAINTAIN THAT THE PILOT ' S CONDUCT WAS MANIFESTLY RECKLESS FOR THE THIRD REASON WHICH IT HAD ADVANCED . IT CONSIDERED SUCH RECKLESSNESS OBVIOUS FROM THE PILOT ' S DECISION TO ENTER THE DISTURBANCE WHICH HE SAW AHEAD OF HIM AND NOT TO TURN BACK IMMEDIATELY IN SEARCH OF AN AIRFIELD WHERE HE COULD LAND .
13 SO AS TO WEIGH UP THAT ARGUMENT IT IS NECESSARY TO CONSIDER THE VARIOUS UNDISPUTED FACTUAL CIRCUMSTANCES SURROUNDING THE LAST MINUTES OF THE FLIGHT IN QUESTION AS WELL AS THE VIEWS WHICH THE TECHNICAL EXPERTS HAVE EXPRESSED ON THEM .
14 THE FIRST POINT TO BE MADE IN THIS REGARD IS THAT THE WEATHER INFORMATION PROVIDED BY LYON-BRON AIRPORT FORECAST A VIGOROUS DISTURBANCE PRODUCING HEAVY LOCAL RAIN BEYOND MONTELIMAR ACCOMPANIED BY A STRONG GUSTING SOUTHERLY WIND WITH VISIBILITY OF 10 TO 15 KILOMETRES , REDUCED TO 6 TO 10 KILOMETRES IN RAIN . THERE WAS NOTHING IN THAT INFORMATION TO INDICATE THAT A SUDDEN AND CONSIDERABLE REDUCTION IN THE VISIBILITY WHICH IS AN IMPORTANT FACTOR FOR PILOTS FLYING VISUALLY LIKE MR VAN KASTEEL , WOULD OCCUR . ACCORDING TO THE OBSERVATIONS MADE BY MARSEILLE-MARIGNANE AT 16.00 HOURS LOCAL TIME , ONE HOUR BEFORE THE PROBABLE TIME OF THE ACCIDENT , VISIBILITY WAS 15 KILOMETRES .
15 THE SEVERE DISTURBANCE WHICH LED TO THE ACCIDENT IN QUESTION WAS THEREFORE NEITHER FORECAST NOR REPORTED BY THE WEATHER STATIONS WHOSE INFORMATION WAS AVAILABLE TO AIRMEN . IT IS ALSO CLEAR FROM THE EVIDENCE OF MR VAN KASTEEL ' S TWO FELLOW-PILOTS WHO WERE ALSO FLYING LIGHT AIRCRAFT THAT THE DECISION TAKEN BY EACH OF THEM TO FOLLOW THE RHONE VALLEY ROUTE AS FAR AS MARSEILLE WAS NOT PROMPTED BY THE WEATHER INFORMATION AVAILABLE TO THEM . MOREOVER , WHILST FOLLOWING THE COAST ONE OF THEM WAS CAUGHT UNAWARES BY VERY STORMY WEATHER AT LA CIOTAT FROM WHICH HE EMERGED ONLY AT SOME RISK .
16 THE INFORMATION PROVIDED BY LYON-BRON ALSO REPORTED THE SKY COVERED BY ALTOSTRATUS AT ROUGHLY 2 400 METRES ABOVE 4 TO 6/8 STRATOCUMULUS BETWEEN 600 AND 1 000 METRES . ACCORDING TO THE EXPERTS ' STATEMENTS , IN SUCH ATMOSPHERIC CONDITIONS THERE IS NORMALLY A CORRIDOR BETWEEN THE CLOUD MASSES WHICH IS HARDLY AFFECTED BY DISTURBANCES . THEREFORE BY FLYING AS HE DID AT AN ALTITUDE OF 1 500 METRES MR VAN KASTEEL DID NOTHING CONTRARY TO THE RULES OF GOOD AIRMANSHIP .
17 IT IS CLEAR FROM THE FOREGOING THAT MR VAN KASTEEL CANNOT BE ACCUSED OF ANY RASHNESS AS REGARDS HIS CONDUCT AS A PILOT UNTIL THE TIME AT WHICH HIS AIRCRAFT ENTERED THE UNEXPECTED DISTURBANCE