e. Most of the damage sustained was consistent with it having fallen on to its inboard end and then on to some rocks. Signs were found, however, of excessive downward movement of this elevator to the extent that the hinges had damaged the steel spar, more so at the outboard hinge where the hinge arm had actually cut into the spar. It was official opinion that pilot applied force could not have caused this damage since the control column movement in restricted by stops strong enough to resist human force.
It is considered that at the time of the excessive downward movement of the elevator, the force, mainly due to leverage over the spar, was sufficient to cause failure of the hinge bolts in tension. Failure of the spar attachment upper lug clearly indicated that the outboard end of the elevator broke away first in a rearward direction. No evidence was found to suggest that this port elevator was attached to the airframe at the time of impact.
Examination of the starboard elevator indicated that its upward travel had been exceeded; this and other damage to this elevator being consistent with crash damage.
Regarding the section of the upper starboard rudder, the outboard skin at the break had failed in tension and the inboard skin was torn away from the front rearwards, this indicating that the broken off portion was first bent inwards and then backwards. Furthermore, apart from damage at the upper leading edge, which was inflicted when the rudder struck the ground, this portion of rudder was altogether undamaged. The rudder was probably detached from the aircraft before the point of impact.
As for the lower portion of the starboard rudder, failures on the outboard and inboard skins correspond to failure on the upper section. Damage on this section would appear to indicate that it did not strike the ground at the point of impact, but that it was flung forwards and carried further assisted by the strong winds prevailing at the time.
Considerable violence coupled with exceptionally strong winds and/or air turbulence was necessary to carry the port and starboard fin, port tailplane and several other pieces of empennage to their final positions. None of these parts, except the starboard fin, displayed any damage that could have occurred at the point if impact.
The port tailplane front spar had pulled out along its length, shearing all its rivets. Examination of the main impact zone indicated that the fuselage struck at right angles to the main mark down the slope and the sideways cartwheel or flick might have thrown empennage parts in to the air forward of, and to the right of, the impact area.
Examination of the point of impact of the port wingtip fuel tank indicated that the angle that the tank struck the ground was such that, had the tank been attached to the aircraft, the empennage should then have hit the ground. The tank was therefore most probably detached from the aircraft while still in the air. Positions of the No. 3 and 4 ailerons and part of the port wing support this reasoning.
The dump valves of both port and starboard tip tanks were found in the fully open position. As these valves are electro-mechanically driven, they were probably intentionally open and most likely before the port tip tank impact since this tank still had a considerable amount of fuel left over in it, judging by the flash fire area. The forward portion of the starboard tip tank, on the other hand, showed no signs of flash fire or explosion, indicating that its fuel content at the time of impact must have been low. The open dump valves appear to suggest that the pilot must have been busy dumping fuel in order to reduce the load on the airframe when it experienced the heavy turbulence and just before the aircraft began disintegrating. The aircraft weighed about 43 213 kg (95,242 lb) at the time of the accident.
In an attempt to reconstruct the events leading up to the crash, another Shackleton of the same weight and load as Shackleton 1718, took off from Runway 34 at DF Malan on August 22, 1963 to attempt to emulate as closely as possible the cou