Opinion ID: 894934
Heading Depth: 3
Heading Rank: 1

Heading: What Ledesma's Two Experts Said

Text: Ledesma's expert David Hall, an accident reconstructionist, testified by deposition that he believed a mark in the road showed that the drive axle struck the pavement before the truck struck the Firebird, consistent with Ledesma's theory that the truck malfunctioned and caused the collision. He reached this conclusion by reviewing a number of photographs. Based on the photographic evidence of damage to the Firebird and an engineering paper providing a method for estimating speed based on the Firebird's body damage, Hall also estimated that Ledesma's truck was traveling at a very slow speed when it struck the Firebird, again consistent with Ledesma's theory of the accident and inconsistent with Ford's theory that Ledesma was speeding and otherwise driving carelessly. Ford raises numerous complaints about the reliability of Hall's testimony. Ford notes that the post-accident photographs of the road were taken by Ledesma and his father with a low-quality disposable camera, that there are many spots and marks on the grainy photographs, and that the marks do not reliably indicate that the drive shaft struck the road prier to the crash with the Firebird. Ford stresses that the investigating police officer found no gouges in the pavement despite a careful search of the accident scene. Ford also raises numerous complaints about Hall's estimate of the truck's speed at the time of the Firebird collision. These complaints include two observations: (1) the engineering paper on which Hall relied states that it should not be used when examining side swipes such as the accident in issue; and (2) the damage to the Firebird, as confirmed by the car's owner and a repair estimate, was far more severe than Hall assumed, rendering his estimate of a very slow impact unreliable. Ford complains that the testimony of Ledesma's principal expert, metallurgical and mechanical engineer Geert Aerts, was likewise unreliable. Ledesma counters that Aerts is a leading expert on truck leaf springs; Aerts has investigated about 150 leaf-spring failures. Ford does not claim that Aerts was unqualified to testify as an expert on the accident in issue but contends that his theory of the accident was unreliable for various reasons. Aerts focused on the u-bolts holding the rear axle to the rear springs and concluded that one of them was defectively manufactured. His theory was that a rear passenger-side u-bolt was loose, causing it to vibrate. This vibration eventually fatigued and fractured a center pin holding the leaf springs to the rear spring plate, which in turn allowed the u-bolts, spring plate, and rear axle to slide backwards, pulling the drive shaft from the transmission. Aerts examined the truck's u-bolts while they were still on the truck and found the torque on each bolt to be well below that required by Ford's specifications. While he conceded that the torques might have changed due to the accident, he concluded that the u-bolt in issue was under-torqued when Ford assembled the truck. Aerts testified extensively about how the th:bolt came to be under-torqued. One explanation was that one leg of the u-bolt was manufactured a few millimeters higher than the other, which could have caused the nut on the shorter leg to receive an insufficient torque when it and other nuts were simultaneously tightened. Aerts claimed that, according to a Ford product engineering sheet for the u-bolt, admitted into evidence, this slight difference in heights of the legs exceeded the tolerance in Ford's own specifications. The engineering sheet provided diagrams and various specifications for the u-bolts. Aerts also testified that the product en gineering sheet required the bottom, curved portion of the u-bolt to be flattened to allow for a better grip on the axle, and that the flattened portion on the allegedly defective bolt was off center by about three-quarters of an inch. According to Aerts, this manufacturing defect reduced the surface area of the bolt in contact with the axle, thus reducing the bolt's grip on the axle. This defect also allegedly allowed the bolt to dig into and deform the axle housing, causing the bolt to further loosen over time. The product engineering sheet clearly shows that the flattened portion of the u-bolt is to be centered at the bottom of the curved portion of the bolt, with flattening forty-five degrees up from either side of the bottom of the bolt, and a blend from flat to round for another forty-five degrees on both sides of the bolt. As further evidence of a pre-accident defect, Aerts focused on the rear spring plate. The u-bolts went through this plate, which sits on top of the leaf springs. The u-bolts were tightened onto the plate with four nuts. The rear spring plate also had a center pin attaching the leaf springs to the plate. Aerts claimed that rust and marks on the spring plate near the hole for the center pin indicated that the u-bolt was loose, allowing the assembly to vibrate and the pin to, scratch the spring plate over a period of time. These observations were consistent with his theory of a u-bolt that was loose before the accident, resulting in vibration that caused the center pin to suffer a fatigue fracture and precipitate the u-bolt slippage and drive shaft dislocation. Aerts also theorized that, perhaps for a reason other than the uneven u-bolt ends and flattened portion of the bolt, Ford simply failed to tighten the u-bolts to the torque required by its own specifications, causing the assembly to vibrate and eventually fail after a few months of driving. Ford challenged Aerts's testimony at every turn. It argued that Aerts never confirmed the existence of denting in the axle housing and that Ford's expert May testified that he could find no such denting. Ford contended that the u-bolt was deformed because of the tremendous forces of the accident. It further offered evidence from May, who was familiar with Ford's manufacturing process, that the sockets on its four spindle nut runner, the machine used to tighten the nuts onto the u-bqlts, are four inches deep, easily deep enough to properly tighten the nuts despite the slight difference in the height of the u-bolt legs. May claimed that the difference in the u-bolt lengths was within Ford's allowable tolerances. May also testified that he could not see the .75-inch misalignment of the flattened portion of the u-bolt that Aerts observed.