§ Mr. Hazellasked the Secretary of State for Defence whether he will make a statement on the findings of the board of inquiry into the mid-air collision between a Canberra and a Victor on 19th August 1968, over the township of Holt, Norfolk.
§ Mr. BoydenYes. The accident occurred when a Canberra from Royal Air Force Germany, which had completed a task on Wainfleet range and was climbing in an easterly direction from the range, collided with a Victor climbing out of Marham in a north-easterly direction. The Canberra pilot contacted the Eastern Radar Station during his climb out from the range and was instructed by the Controller to turn 30 degrees right for identification. There were many thunderstorms in the area and the dense weather returns made identification on the Primary Radar impossible. The Controller therefore had changed to the "Secondary Radar only" display in order to achieve it. Although this display provides a positive means of identification it cannot be used to maintain radar control because only an aircraft transmitting a radar signal can be seen by the Controller. Having achieved identification, the Controller advised the pilot to revert to normal navigation. One minute and twenty seconds later the Canberra collided with the Victor in cloud.
The Victor had been using the standard lane for climbing out of Marham, with some small variations to avoid the heaviest weather. The pilot obtained some assistance from the Midland Radar Station in avoiding thunderstorms on the climb, but the Controller had great difficulty in identifying the aircraft owing to the abnormally heavy weather returns on Primary Radar. These weather returns 267W concealed the approaching Canberra from him. Conversely the Eastern radar Controller did not see the Victor on the Secondary Radar.
The Board's finding was that the cause of the accident was the abnormal weather conditions coupled with the unsatisfactory performance of the ground radar in these conditions.
We are naturally much concerned to ensure that there will not be another tragic accident of this kind. The odds against such an accident are of course immense; but full assurance will be possible only when the existing radars have been replaced by more modern equipment which will not be seriously affected by thunderstorms. Meanwhile work is in hand on improving the effectiveness of existing radars; mandatory new penetration and departure procedures for aircraft using the ranges on the coast of East Anglia have been introduced, together with certain new restrictions on flying by other military aircraft in the area.