Opinion ID: 1374687
Heading Depth: 1
Heading Rank: 2

Heading: The Post-Accident Investigations.

Text: Officials of the National Transportation and Safety Board (the Board)responsible for investigating airplane crashesarrived the day after the crash, February 16, 1983, to investigate. Representatives of Sierra Pacific, deHavilland, and Western Aircraft Maintenance joined the Board, at its request, to provide technical assistance for the investigation. The Board investigated all aspects of the accident. Attention ultimately turned to the malfunctioning elevator and elevator trim tabs, located in the tail of the plane. The investigators discovered that a bolt, nut, and cotter pin, which were supposed to be connecting the elevator devices to the pilot's connecting rod, were missing. The investigators knew that the bolt, nut, and cotter pin had not been torn away or dislodged as a result of impact, because there was no deformation of the bolt hole or in the connecting rod. Despite the crash, the tail section of the plane remained intact. Thus, one investigatorsearching for the missing nut, bolt, and cotter pinfound one single bolt at the bottom of the tail. No cotter pin or nut were ever found. Metallurgical and ultrasound testing, and microscopic examination of the bolt, conducted by the Board, showed that it had been the bolt connecting the pilot's connecting rod with the elevator devices at least from the time when the plane was repainted in 1981. The test results also showed that no nut or cotter pin had ever been used to secure the bolt, and that the bolt had worked its way out over time, holding the connecting rod to the elevator devices merely by tension. Further examination of the bolt showed that it was far shorter and of less strength than the type of bolt deHavilland specifies in its parts catalogue manuals. The bolt was so short, in fact, that it could not have been properly secured with a cotter pin and nut had there ever been an attempt to do so. Markings on the outboard side of the connecting rod also showed that the bolt had been inserted with its face outward. This contravenes deHavilland specifications, which state that the head of the bolt should face inward. The reason for this distinction is that, structurally, proper installation of the bolt, nut, and cotter pin is virtually impossible when the head of the bolt faces outward; there is very little room behind the connecting rod in which the nut and cotter pin can be attached. Furthermore, inspection of the nut and cotter pin would be more difficult if the head of the bolt were facing outward, because a mechanic would have to use mirrors or his hand to see if the nut and cotter pin were properly secured. The Board's metallurgical evidence and investigation substantiated the physical evidence discovered at the accident scene. The evidence explains why pilot Moline lost elevator control during flight: the bolt found in the bottom of the tail section had not been properly secured, and had worked its way out over time, finally falling out during the final landing approach on February 15, 1983. The question of how this could have occurred was also investigated by the Board. In December 1981, Sierra Pacific repainted the plane which crashed in this case. This required, in part, a Sierra Pacific mechanic to remove the elevators for repainting. During the repainting, Sierra Pacific mechanics also disassembled and inspected the various elevator devices and connecting rods. Reinstallation of flight controls is a required inspection item. Federal Aviation Administration rules require one mechanic to perform the installation, another independently to inspect the installation, and both to sign what is known as an M-6 work order form. This form allows investigators to accurately trace the plane's maintenance history. Thus, pursuant to FAA rules, the first Sierra Pacific mechanic should have secured the connecting rod to the elevator devices with a properly specified bolt, castellated nut, and cotter pin. A second mechanic should then have looked at this connection to ensure that it was secure. Both individuals should also have signed the M-6 form showing that they had performed their required duties. When the Board examined Sierra Pacific's M-6 forms, they found forms showing disassembly of the plane's flight controls and inspection of those parts. The M-6 form showing reassembly and inspection of those flight controls was never found. Sierra Pacific has never offered an explanation for this gap in its recordsa shockingly large and illegal gap. At the time Sierra Pacific was repainting and doing the maintenance work on the plane in issue here, it also was having the exact work done on two other identical planes. The Board found M-6 forms showing reinstallation of flight controls on these two other planes. This makes the absence of the M-6 form detailing flight control reassembly on the defective plane even more suspect. There is an M-6 form which does show that a reinspection of the instant aircraft's connecting rod and elevator devices was performed on November 5, 1982. Two Sierra Pacific employees signed the M-6 form indicating that they inspected the various connections and devices. The fact is, however, that had the inspection been properly conducted, the improper bolt and lack of a nut and cotter pin would have been discovered. This was testified to at trial by several mechanics. [1] Accordingly, the jury could have concluded that Sierra Pacific employees either lied about their performing these required inspections, or did the inspection in a grossly negligent way, callously and shockingly permitting the unfastened bolt to continue to hold the elevator control devices together by mere tension.