Page:CAB Aviation Accident Report, Mid-Air Collision on 15 December 1959.pdf/7

- 7 - provided a good foundation for an accurate analys1s of these important considerations.

Analysis of the factual information and physical evidence leads the Board to the determination that the inflight contact sequence began with the Beechcraft on a heading of 154-degrees and the F-86L on a heading of 110 degrees. Initial inflight contact occurred when the F-86L nose structure contacted the fuselage of the Beechcraft Just behind the right rear cabin window. The sequence progressed as the nose structure above the wing of the F-86L penetrated and out through the Beechcraft fuselage at an angle of 110 degrees to the fuselage centerline measured clockwise from.the nose. Forces attending the sequence sheared off the Bonanza fuselage aft of the swath line while the right wing of the F-86L most probably passed below the plane of the wings of the Beechcraft.

Because the colliding F-86L was in straight and level flight during the sequence and because the wings of neither aircraft made contact it is most apparent the Bonanza was also straight and level. This is substantiated by the lack of any vertical deformation to the structure involved in the collision. These factors cause the Board to believe that no evasive action occurred which would indicate the Bonanza pilot saw the F-86L's during the collision closure.

As part of the Board's analysis a vector diagram, Attachment A, was prepared using the aforestated factual material necessary to the study. In this manner the probable flightpaths of the aircraft were determined for the 60-second period of closure prior to the collision. From the study it was poss1ble to determine the relative position of each aircraft to the other at any given period. Similarly, it was possible to assess the opportunities afforded each pilot to have sighted the other's aircraft in order to avoid the collision.

The study shows that at the beginning of the 60-second period the colliding aircraft were separated 3.48 statute miles. At this time the Beechcraft was located 67 degrees to the left of the nose of the Jet formation leader's aircraft. It would have been slightly above the leader and Visible to him through the canopy glass, presenting a quartering rear profile. During the first 30 seconds, while the F-86L's were turning, the angular position of the C-35 gradually shifted to a pos1tion about 26 degrees to the left of the nose of the leader's aircraft and to approximately eyelevel. During the final 30 seconds, with formation straight and level, the position of the Beechcraft would remain unchanged.

The study also shows that at the beginning of the 60-second period the F-86L formation was positioned 129 degrees to the right rear of the nose of the Beechcraft or approximately 40 degrees to the rear of the 90-edegree position. The jets would have been below the level of the Beechcraft. During the first 30 seconds the pos1tion of the jet formation would gradually shift forward until it was positioned level at a sighting angle of 110 degrees to the right rear of the nose of the C-35. During the final 30 seconds this position would remain unchanged.

From the available evidence and analytical study of this accident it is the conclusion of the Board that an overtaking situation occurred in which the F-86L formation overtook the Beechcraft from its right rear. The Board concludes that during the 60-second period of closure the Beechcraft was positioned well within the forward visual quadrant of the jet formation leader and that it presented an