Products Liability Law Daily Wrap Up, EXPERT EVIDENCE—INDUSTRIAL AND COMMERCIAL EQUIPMENT—S.D. Tex.: Expert evidence moves forward in part in service technician’s injury suit against mower maker, (Sep 5, 2025)

By Pankhuri Bhatnagar, B.A. LL.B.

The technician’s expert testimony proceeded since the expert was an economist qualified to project the amount of the technician’s lost wages, and his calculations were reliable.

In an action brought against a mower manufacturer by a service technician who was injured when the mower spontaneously activated and struck him, a federal district court in Texas largely granted the man's motion to exclude the manufacturer’s expert. The manufacturer’s engineer’s opinions on the technician’s failure to read and follow the product manual instructions and warnings would be unhelpful to a jury as they were based on self-evident observations or had no bearing on the man’s claims. However, the engineer’s rebuttal of the technician’s expert’s proposed alternative design was permitted as it was up to a jury to determine whether to credit those opinions (Wolt v. Embankscape Equipment, LLC, No. 4:22-cv-02503 (S.D. Tex. Sept. 3, 2025)).

Background. The mower at issue was originally manufactured by Ariens Company, d/b/a Gravely, to be manually operated. Subsequently, it was redesigned, manufactured, and sold as a remote-controlled mower by Embankscape Equipment, LLC d/b/a RC Mowers USA (manufacturer). A technician employed by a third party performed a service update issued by RC Mowers on the product but later found the mower unresponsive to the remote transmitter. He placed the actuators in neutral using the remote and approached to manually release the parking brake. Upon doing so, the mower spontaneously activated, moved forward, and knocked over the technician. The man claimed that his injuries resulted in permanent impairments. He and his wife (claimants) brought suit against various entities alleging a design defect, marketing defect, and negligence. Claims brought against the original mower manufacturer and the transmitter suppliers (Kar-Tech, Inc. and Kar-Tech Global, Inc.) were settled, leaving only the claims against RC Mowers. The parties moved to exclude each other’s experts.

Technician’s expert. The manufacturer sought to exclude the opinions of the economist who projected the amount of the technician’s lost wages, claiming that there was no factual basis to indicate that the man would stop working in 2026 and that the expert’s accounting background did not qualify him to opine about the man’s ability to work. The claimants explained that a jury would determine whether the man’s injuries rendered him unable to work, on what date that would occur, and what sum of lost wages (if any) to award. The economist merely applied his expertise to quantify what the lost wages would be on a yearly basis, taking inflation into account, over a range of time starting from 2026. RC Mowers did not challenge the calculations, which the expert’s background qualified him to perform. Since its motion only attacked opinions the economist did not actually provide, the motion to dismiss the man’s expert evidence was denied.

Manufacturer’s expert. The claimants first argued that RC Mower’s engineer’s opinions about the technician’s failure to review and adhere to instructions and warnings and the attendant consequences should be excluded as they presented nothing helpful to a trier of fact as required by Fed. R. Evid. 702(a). In his report, the engineer cited product manual warnings and instructions which the man did not follow (such as standing 30 feet away when operating the unit and turning off the engine before approaching the mower) and then concluded that had the manual been followed, the subject incident would not have occurred. The court noted that his observations were self-evident since the instructions were straightforward and a jury was capable of reading them and “determining from the evidence” whether the man complied with them. J.S. v. Am. Inst. for Foreign Study, Inc. (W.D. Tex. Sept. 24, 2013). As held in Crow v. United Benefit Life Ins. Co. (N.D. Tex. Mar. 16, 2001), expert testimony on issues that “a jury is capable of assessing for itself” is properly excluded as unhelpful. Thus, these opinions did not survive.

Next, the engineer opined that the manufacturer “provided reasonable instructions and warnings to operators, users, and service providers for [the mower’s] safe use.” The claimants pointed out that the expert was not qualified in human factors aspects of product-safety warnings to render this opinion. RC Mowers argued that the statement meant that the warnings “were reasonable to allow [the technician] to determine the intended use of the Mower as designed.” But experts are only allowed to testify about opinions disclosed in the report. Fed. R. Civ. P. 26(a)(2)(B)(i). Moreover, whether the engineering expert found the warnings adequate did not inform whether a non-engineer service technician was adequately warned of hazards associated with the mower’s intended or foreseeable use. In addition, whether the user was able to determine the mower’s “intended use” had no bearing on the design defect and marketing claims in this case, since reference to warnings and instructions is only a small piece of the risk-utility inquiry and knowledge of the existence and avoidability of dangers that are commonly known or warned against “is not an absolute bar... to liability for a defective design.’” Erwin v. Metalcraft of Mayville, Inc. (N.D. Tex. Mar. 20, 2025). As such, the testimony’s likelihood of confusing the jury significantly outweighed its probative value and it was due to be excluded.

The claimants accurately pointed out that the opinion that the “Service Procedure SP111 was an accompanying reference to the [mower’s] Manual and not intended or suggested to be a standalone manual” was not based on any supporting facts or analysis, amounting to inadmissible ipse dixit. RC Mowers acknowledged that another challenged opinion—that the mower “was reasonably safe for its intended and reasonably foreseeable usage by intended persons as designed”—was premised on opinions deemed inadmissible and was also precluded. Finally, four of the disputed opinions rebutted the conclusions of the technician’s expert that the accident was foreseeable and there existed reasonable alternative designs for the mower. Although the four opinions overlapped with the excluded opinions (since the engineer maintained that the man’s failure to read the instructions refuted the assumption that an alternative design would have prevented the accident), the court held that the engineer should not be precluded from making the rebuttals as the jury was yet to determine facts such as whether the man read and complied with the manual instructions. Accordingly, the motion to dismiss the engineer’s evidence was granted in part.

The case is No. 4:22-cv-02503.

Judge: Ho, Y.

Attorneys: James Kendon Allen Womack (Sloan, Hatcher, Perry, Runge, Robertson & Smith) for Leon Wolt and Debra Wolt. Michele Y. Smith (MehaffyWeber PC) for Embankscape Equipment, LLC d/b/a RC Mowers USA. Clinton Vaylord Cox, IV (Cox PLLC) for Kar-Tech, Inc. and Kar-Tech Global, Inc.

Companies: Embankscape Equipment, LLC d/b/a RC Mowers USA; Kar-Tech, Inc.; Kar-Tech Global, Inc.

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