--- title: "Forensic Engineering Expert’s Testimony on Brake Levers Admitted" meta: "og:description": "The forensic engineering expert was allowed to testify because he considered seven categories of evidence in reaching his conclusion" "og:title": "Forensic Engineering Expert’s Testimony on Brake Levers Admitted" author: "Expert Witness Profiler" description: "The forensic engineering expert was allowed to testify because he considered seven categories of evidence in reaching his conclusion" --- # Forensic Engineering Expert’s Testimony on Brake Levers Admitted Posted on November 27, 2025 by Expert Witness Profiler Plaintiff Matthew Hartley sued Defendants Sunbelt Rental Inc. and Custom Equipment LLC to recover for personal injuries he sustained during a jobsite incident on June 14, 2021. Plaintiff alleged that on June 14, 2021, he “attempted to move a Sunbelt Rentals Hy-Brid Lift HB-1030 down a ramp when suddenly and without warning it began to rapidly roll down the slope of the ramp despite no effort on his part to power the lift forward.” He further alleged that the lift, which was manufactured by Custom Equipment, LLC, “rolled uncontrollably into a concrete wall at a rapid rate of speed” causing “debilitating physical injuries” and a variety of economic and noneconomic harms. Plaintiff retained Craig Sylvester, a forensic engineering expert, to determine the “root cause” of the accident. According to Sylvester, “the root cause of the incident on June 14, 2021 was a mis-wired emergency stop button, as well as the placement of one or both of the parking brake levers at the rear of the machine in an intermediate position.” Defendant Custom Equipment filed a motion to strike certain expert opinions and limit testimony of disclosed expert [Craig Sylvester](https://expertwitnessprofiler.com/expert-witness/Craig-Sylvester/1569155). ## **Forensic Engineering Expert Witness** [Craig A. Sylvester](https://expertwitnessprofiler.com/expert-witness/Craig-Sylvester/1569155) is a former U.S. Navy mustang officer and licensed mechanical engineer with more than 25 years of experience as an operator, maintainer, designer, and inspector of industrial equipment around the world. Sylvester’s expertise in industrial systems is built on his early work performing component-level repairs as an electronics technician, along with formal education in manufacturing and mechanical engineering, and naval architecture. [Want to know more about the challenges Craig Sylvester has faced? Get the full details with our Challenge Study report](https://expertwitnessprofiler.com/order/add?eId=1569155&pId=3). ## **Discussion by the Court** ### **Parties’ Arguments** Defendant requested the Court “exclude the portions of Sylvester’s opinions that are untimely, speculative and unhelpful to the jury.” Defendant argued that exclusion is warranted because Sylvester’s: (1) supplemental opinions on electromagnetic braking assistance, back emf braking assistance, and arc suppression circuits are untimely and unhelpful to the jury; (2) opinions on the intermediate position of the brake levers are speculative; (3) opinions on the parking brake’s holding torque are unhelpful to the jury; and (4) opinions that the pre-start inspection checklist failed to adhere to the ANSI A92.22 standards are unhelpful to the jury. Plaintiff contended, and Defendant accepted, that “Sylvester has no intention of testifying that the HB 1030 should have included ‘electromagnetic,’ ‘back emf’ or an ‘arc suppression circuit’ at the time of trial.” The Court thus found these admissibility questions to be moot. Plaintiff also stated that Sylvester “will not be testifying regarding [the holding torque] document” and that the “[ANSI A92.22] standards, which were adopted after the manufacture and sale of the HB 1030, would not apply to [the unit at issue.]” As Defendant did not challenge the admissibility of testimony by Sylvester that “industry standards would include a pre-start inspection of the braking system as a matter of common sense and industry standards” nor do they otherwise challenge Plaintiff’s concessions on these issues, the Court likewise found these admissibility questions moot. ### **Court’s Decision** The Court concluded that Sylvester’s opinions on the intermediate position of the brake levers “both rests on a reliable foundation and is relevant to the task at hand.” As for relevancy, the Court found that Sylvester’s opinions on the intermediate position of the brake levers will “assist the trier of fact” to determine the root cause of the June 14, 2021 incident. As the root cause of the incident is “a fact in issue,” Sylvester’s testimony satisfied the standard for relevancy. The Court also concluded that Sylvester reviewed numerous sources of information, utilized reliable principles and methods of forensic engineering, and reliably applied said principles and methods to the facts of the case. The Court noted that Sylvester “considered seven categories of evidence in reaching his conclusion, only one of which was a document generated during the course of BN Builders investigation, which occurred shortly after the incident in question.” As a result, the Court declined to exclude Sylvester’s testimony on the brake levers as “speculative.” ## **Held** The Court denied the Defendant Custom Equipment LLC’s motion to exclude the testimony of Plaintiff’s expert Craig Sylvester. ## **Key Takeaway:** The Court noted that while Defendant raised various other arguments for exclusion, none of these arguments provided a proper basis for exclusion, as they all speak to issues of fact-finding, not gatekeeping. For example, Defendant’s disagreement with Sylvester’s exclusion of other possible explanations for the accident and his reasons for doing so do not render his opinions inadmissible—they merely make it more likely that the trier of fact will view Sylvester’s conclusions about the root cause of the accident less credible.  Because the Court must act as “a gatekeeper, not a fact finder,” it cannot exclude portions of Sylvester’s testimony for any of these fact-finding based reasons. ## **Case Details:** --- ## **You Might Also Like** ![Human Resources Expert Allowed to Opine on Termination](https://ewp-blog.expertwitnessprofiler.org/wp-content/uploads/2026/04/blog-pic-640X480-2026-04-22T200052.311.jpg) [**Human Resources Expert Allowed to Opine on Termination**](https://expertwitnessprofiler.com/forensic-engineering-experts-testimony-on-brake-levers-admitted/human-resources-expert-allowed-to-opine-on-termination)![Neuropsychology Expert Not Allowed to Opine on Cognitive Decline](https://ewp-blog.expertwitnessprofiler.org/wp-content/uploads/2026/04/blog-pic-640X480-2026-04-22T144728.528.jpg) [**Neuropsychology Expert Not Allowed to Opine on Cognitive Decline **](https://expertwitnessprofiler.com/forensic-engineering-experts-testimony-on-brake-levers-admitted/neuropsychology-expert-not-allowed-to-opine-on-cognitive-decline)![Human Factors Expert Not Allowed to Opine on the Tile](https://ewp-blog.expertwitnessprofiler.org/wp-content/uploads/2026/04/blog-pic-640X480-2026-04-21T191749.960.jpg) [**Human Factors Expert Not Allowed to Opine on the Tile**](https://expertwitnessprofiler.com/forensic-engineering-experts-testimony-on-brake-levers-admitted/human-factors-expert-not-allowed-to-opine-on-the-tile)![Insurance Expert Not Allowed to Opine on Legal Duties](https://ewp-blog.expertwitnessprofiler.org/wp-content/uploads/2026/04/blog-pic-640X480-2026-04-21T155751.487.jpg) [**Insurance Expert Not Allowed to Opine on Legal Duties**](https://expertwitnessprofiler.com/forensic-engineering-experts-testimony-on-brake-levers-admitted/insurance-expert-not-allowed-to-opine-on-legal-duties)![Law And Legal Expert Not Allowed to Opine on Contract Formation](https://ewp-blog.expertwitnessprofiler.org/wp-content/uploads/2026/04/blog-pic-640X480-2026-04-20T213123.718.jpg) [**Law And Legal Expert Not Allowed to Opine on Contract Formation**](https://expertwitnessprofiler.com/forensic-engineering-experts-testimony-on-brake-levers-admitted/law-and-legal-expert-not-allowed-to-opine-on-contract-formation)