Expert Witness Profiler

Tag: Root Cause

  • Forensic Engineering Expert’s Testimony on Brake Levers Admitted

    Forensic Engineering Expert’s Testimony on Brake Levers Admitted

    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.

    Forensic Engineering Expert Witness

    Craig A. Sylvester 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.

    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:

    Case Caption: Hartley V. Sunbelt Rentals, Inc
    Docket Number: 2:24cv1078
    Court Name: United States District Court, Washington Western
    Order Date: November 24, 2025
  • Automotive Engineering Expert Witness’ Testimony Regarding the Latent Defect in Airbag Inflators Admitted

    Automotive Engineering Expert Witness’ Testimony Regarding the Latent Defect in Airbag Inflators Admitted

    Plaintiff, William Harrison Sims’ claims arise out of an October 24, 2019, two-vehicle collision involving Plaintiff, who was operating the 2004 BMW (“Subject BMW”). Tameca Harris-Jackson (“Harris-Jackson”) was operating the Hyundai that collided with the Subject BMW. Plaintiff alleges he sustained “severe, permanent, and life-altering injuries” due to the driver-side Takata airbag unexpectedly rupturing and shooting “metal shrapnel into his face and body.”

     Defendants procured and installed the airbag inflator during the process of “designing, manufacturing, assembling, and producing” the vehicle. Plaintiff brought this action for damages against both Defendants BMW of North America (“BMW NA”) and Bayerische Motoren Werke AG (“BMW AG”), alleging strict liability and negligence from procuring and installing the airbag.

    Plaintiff submitted that Mr. Robert C. Lange, BMW’s mechanical engineer, is prepared to opine that he is unaware of any evidence showing the Defendants “could have been aware air bag systems supplied by Takata to BMW AG were defectively designed prior to Takata’s announcement of defect findings beginning in 2014.” 

    Lange will also opine that when the subject 2004 BMW was distributed by BMW NA, “no motor vehicle manufacturer or distributor could have known of the technical research findings regarding the latent defect in Takata air bag inflators because the science was not settled until 2015-2016.”

    He also contended that Takata falsified data provided to vehicle manufacturers through 2015 and failed to correct the false data once the defect was discovered. Plaintiff argued that Lange’s opinions were unsupported and unreliable. 

    Automotive Engineering Expert Witness

    Robert Lange has over 50 years of experience in automotive engineering. He specializes in motor vehicle systems architectures, structures, safety, and public health.  

    Lange has experience in statistical analysis of motor vehicle service performance databases, statistical forecasting and reliability analysis, FMEA and failure mode avoidance methods, collision-related data acquisition and analysis, safety rulemaking, strategy, and the like. 

    Get the full story on challenges to Robert Lange’s expert opinions and testimony with an in-depth Challenge Study. 

    Discussion by the Court

    The issue is whether Lange’s opinions are based on sufficiently reliable methods and principles. If they are, then Lange’s opinions are undoubtedly helpful to the jury. If his opinions are unsupported ipse dixit, they must be excluded. 

    Lange’s Methodology and Opinions

    Plaintiff contended that BMW knew that the subject vehicle was defective because the airbag inflator used phase-stabilized ammonium nitrate (“PSAN”) as the airbag’s propellant, causing the inflator to rupture when the airbag deployed during the accident. 

    Lange discussed his investigation into the Takata air bag failures. He noted that Honda conducted the first recall of Takata air bag systems for inflator failure in a letter dated November 11, 2008. 

    National Highway Traffic Safety Administration (“NHTSA”) hired Dr. Harold Blomquist to assist in its Takata defect investigation and issued his report in 2015. 

    Documents from the Recall Query revealed that Takata represented to Honda that the ruptures were caused by a “Stokes press” that forms propellant into a wafer, causing the propellant to burn too quickly and rupture the inflator. Accordingly, in 2010, Honda expanded the recall to include the new basis. Between 2010 and 2013, Honda and Takata continued to receive reports of inflator ruptures, and Takata retained consultants to conduct a root cause analysis. 

    Takata’s root cause analysis continued, and in 2014, research pointed to moisture and temperature in high absolute humidity regions as causing an increased propellant burn rate. Lange, however, concluded that “during the inflator development phases, Takata falsified data provided to vehicle manufacturers. When the false data was discovered, Takata failed to correct the false data by informing the manufacturer and correcting the record.”

    Plaintiff’s Objections

    Plaintiff challenged the admissibility of the following opinions offered by Lange:

    75. I am unaware of any evidence showing BMW AG and BMW NA could have been aware air bag systems supplied by Takata to BMW AG were defectively designed prior to Takata’s announcement of defect findings beginning in 2014.

    76. As of the date of distribution of the Subject 2004 BMW 330Ci, by BMW NA, no motor vehicle manufacturer or distributor could have known of the technical research findings regarding the latent defect in Takata air bag inflators. The science was not settled until 2015-2016.

    Plaintiff also challenges the following statement made by Lange:

    “During the inflator development phases, Takata falsified data provided to vehicle manufacturers. When the false data was discovered, Takata failed to correct the false data by informing the manufacturer and correcting the record. Takata’s false dealings with vehicle manufacturers evidently extended into 2015.”

    Plaintiff contended that Lange will confuse the jury if permitted to offer evidence that Takata lied to other vehicle manufacturers without having proof Takata lied to BMW. Moreover, Lange “knows little about the relationship between BMW and the supplier of the defective airbag inflator at issue in this case, Takata.”

    Plaintiff also argued that Lange’s opinion that he is “unaware of any evidence” showing BMW’s knowledge of the defect is not helpful to the jury. Plaintiff asserted that Lange failed to inform himself on the subject matter sufficiently, and his lack of evidence that BMW was aware of the risks attendant to using PSAN does not equate with BMW’s lack of knowledge.

    Ruling

    Lange has extensive experience working at Ford Motor Company, Failure Analysis Associates, and the General Motors Corporation. During his work with Ford, Lange was responsible for vehicle design and remedying safety defects serviced as recall actions. As the Safety Executive with General Motors, Lange oversaw research projects involving air bags, occupant restraint systems, driver assist technology, and other vehicle systems. He also supervised the “Product Investigations” Department and was responsible for identifying potential safety defects and initiating investigations. In other words, the Court held that  Lange possesses the requisite experience to review the data, investigative reports, and shifting root-cause analysis discussed in his report.

    On balance, the Court did not find that Lange’s opinions rest on mere ipse dixit and instead are based on his review of relevant documents showing Takata’s shifting root cause analysis. Takata initially focused on a manufacturing defect before conceding that the defect had broader implications, which was consistent with Takata hiding the ball from BMW. Basing one’s opinions on the Honda recall and subsequent NHTSA investigations to conclude that the science was not settled until the mid-2000s is a sufficiently reliable methodology. Lange’s opinion that BMW NA was not responsible for the defective design of the subject inflator and that BMW was not on notice until around 2015 was supported by these evolving investigations. 

    Held

    The Court denied Plaintiff’s motion to exclude certain opinions of Robert C. Lange.

    Key Takeaway:

    Lange reviewed the data, investigative reports, and shifting root-cause analysis to conclude that Takata falsified data provided to vehicle manufacturers through 2015 and failed to correct the false data once the defect was discovered.

    Case Details:

    Case Caption: Sims V. Bmw Of North America LLC
    Docket Number: 6:22cv1685
    Court: United States District Court, Florida Middle
    Order Date: February 20, 2025

    Please refer to the blogs previously published about this case:

    Accident Reconstruction Expert Witness’ Testimony Admitted Despite His Failure to Calculate G-Force 

    Neurology Expert Witness’ Injury Causation Testimony Admitted

    Accident Reconstruction Expert Witness’ Opinion Regarding Plaintiff’s Lane of Travel Ignored Physical Evidence