Mechanical Engineering Expert Witness Opinions on Design Defects and Manufacturing Defects Admitted

Mechanical Engineering Expert Witness Opinions on Design Defects and Manufacturing Defects Admitted

Plaintiff Patricia Medellin filed a lawsuit to recover damages for severe injuries she suffered when she fell while using Defendant’s Little Giant Velocity Ladder, a multi-use ladder with adjustable features. The ladder could be configured into various climbing systems, including an extension ladder. Medellin asserted that the “Rock Locks” (version 2.1), which were the locking mechanisms on either side of the ladder used to secure the extension sections at the user’s chosen height, failed to function properly. This alleged failure resulted in the Rock Locks not securing the ladder in its extended position, leading to Medellin’s fall from height.

On November 29, 2019, Patricia Medellin and her fifteen-year-old grandson, Benjamin Jones, were hanging Christmas lights along the roof of Medellin’s home. They unfolded the ladder and extended it until hearing the Rock Locks “click” into place, indicating proper security. At some point after Medellin climbed the ladder, she heard clicking sounds as the top of the ladder retracted downward, and the bottom of the ladder slid away from the house. Benjamin Jones also heard clicking sounds and observed the ladder telescoping down. Medellin fell with the ladder, landing face-down on it. As a result, Medellin alleged she sustained multiple bodily injuries.

Medellin alleged that the Defendant had “defectively designed and manufactured” her ladder and “provided improper warnings and instructions.” According to Medellin’s expert witness, Stanley A. Kiska, the Rock Locks could be inadvertently set in a “false lock” condition, where “the extended section of the ladder is able to remain in place and may appear to be locked to the user, but, in fact, it is not properly and completely secured.” When in this false lock condition, the ladder gives the illusion of being securely locked, though it is not. The ladder, when in a false-locked condition, would retract (i.e. shorten) under the user’s weight during a climb, resulting in both the ladder and the user falling.

The Defendant moved to exclude Stanley Kiska’s testimony and sought summary judgment. The case had been referred to the Magistrate Judge Peter Bray in accordance with 28 U.S.C. § 636(b)(1). The Judge Peter Bray gave his recommendation after reviewing the motions, the responses, and relevant legal provisions.

Mechanical Engineering Expert Witness

Stanley A. Kiska, a licensed professional engineer holding a Bachelor of Science degree in Mechanical Engineering, has a comprehensive background in ladder-related matters. With a 16-year tenure as a Product Engineer/Senior Product Engineer at the Werner Ladder Company, he garnered extensive expertise in ladder design, development, testing, manufacturing, and quality control. Currently, Kiska serves as an independent engineering consultant for Integra Engineering, PC, specializing in forensic engineering and investigating hundreds of ladder and scaffolding accidents. He has applied forensic engineering principles to develop opinions, write reports, and provide expert witness testimony in depositions and trials, representing both Defendants and Plaintiffs. With over 35 years of experience, his qualifications underscore his proficiency and authority in the field.

Discussion by the Court

Stanley Kiska’s opinion was that Medellin’s ladder could be placed in a false locked condition on the ground, set into position for use, and partially climbed without revealing the false locked condition to the user. He reached this opinion after reviewing deposition testimony from Medellin and Jones, examining photographs and videos of Medellin’s ladder, and inspecting both the ladder itself and the site of Medellin’s accident. Additionally, Kiska studied reports and video demonstrations of testing conducted by another of Medellin’s experts, Peter J. Poczynok, P.E., in a separate federal case (Davis v. Little Giant Ladder Sys., LLC, 2:19-cv-00780-SPC-NPM (M.D. Fla.)). Kiska also consulted with Poczynok during the process.

The Davis lawsuit involved the identical ladder model, the same version of Rock Locks, and the same false lock claim as the present case. Poczynok’s testing and reports in Davis, which were attached to Poczynok’s declaration in this case demonstrated that ladders with Rock Locks version 2.1 could be set in the false lock condition and positioned for use while still falsely locked. Additionally, Poczynok illustrated that the false lock could disengage after a user’s weight was applied to the ladder’s rungs. In his declaration for this case, Poczynok stated that, during his work on the Davis case, he “was able to place the locks in a false lock condition when he set up the ladder on the ground, then raised it into position.” He further mentioned that he had “on numerous occasions placed the locks in a false lock condition, on the ground, on the same model ladder that was involved in Medellin’s incident, including Medellin’s ladder, and had been able to set the ladders into a raised and upright position with the false lock intact.” Kiska reviewed and incorporated Poczynok’s testing and opinions into his analysis of Medellin’s accident.

While the Defendant raised multiple complaints about how Kiska relied on Poczynok’s testing, it’s noteworthy that the Defendant did not move to exclude Poczynok’s opinions. Poczynok had been designated as an expert witness in the case and was permitted to testify at trial, specifically about his opinion that the ladder could be placed into a false lock condition on the ground and then raised into position without disturbing that condition. The Defendant clarified that it strategically chose to “utilize Poczynok’s testing videos to highlight elements absent from Medellin’s accident”. Additionally, the Defendant did not object to Kiska relying on Poczynok’s testing. The objection was solely directed at Kiska’s opinions that Medellin was able to (1) set her ladder into a ‘false lock’ condition on the ground and (2) raise it into position without disturbing the condition.

Kiska based the objected-to opinion on various sources of information and his extensive professional engineering experience in the field. He drew upon Poczynok’s testing, conducted his own inspection of the ladder, and considered the eyewitness testimony of both Medellin and her grandson. The Defendant failed to present any valid reason for asserting that Kiska’s reliance on these information sources was improper. It was entirely appropriate for Kiska to rely on Poczynok’s opinions, as the Federal Rules of Evidence allow experts to base their opinions on the opinions of other experts, according to the Advisory Committee’s Notes to the 2000 Amendments of Fed. R. Evid. 702.

The Defendant heavily criticized Poczynok’s testing methodology and opinions but framed these complaints as arguments against Kiska’s reliance on Poczynok’s opinions, rather than directly moving to exclude Poczynek as an expert. The Defendant argued, in the context of seeking to exclude Kiska’s opinions, that Kiska could not rely on Poczynok’s opinions because there was “no established protocol or general acceptance of such testing.” However, the Defendant made a strategic choice not to challenge Poczynok as an expert and expressed the intention to cross-examine Poczynok at trial as part of its defense. Therefore, any attempt by the Defendant to challenge Poczynok’s opinions under the guise of objecting to Kiska’s reliance on those opinions was not presented before the Court at this juncture.

The Defendant contended that Kiska was obligated to validate or replicate Poczynok’s testing before relying on it, a requirement the Court found no awareness of. Contrary to the argument, as discussed in the preceding paragraph, Kiska was only required to ensure that the other experts he relied on were reliable. Poczynok’s reports were deemed to meet this standard, being detailed, inclusive of photos, describing his testing, and outlining his methodology. Kiska thoroughly reviewed these materials and integrated them into his analysis.

The Defendant argued that Poczynok’s testing could not be reliably applied to the context of Medellin’s accident due to several reasons: (1) the pitch of Medellin’s roof was more distinct than the roof on which Poczynok conducted his testing; (2) in four of Poczynok’s ten tests, the ladder was extended well beyond the roofline, making those tests inapplicable to Medellin’s accident, a point conceded by Kiska; (3) of the remaining six applicable tests, only two showed the ladder contracting and losing contact with the roof, resulting in the climber falling; (4) in the two tests where the climber fell, the ladder did not slide straight back, as in Medellin’s case, but instead rotated out from under the climber due to the roof’s pitch; and (5) none of the ten tests replicated the “clicking” sound described by Medellin and Jones.

The Court was not convinced that the distinctions between Poczynok’s tests and Medellin’s accident rendered the tests inadmissible. Even if Poczynok’s tests were not intended to precisely recreate Medellin’s accident, the Court emphasized that recreations must only be “substantially similar” to provide a fair comparison, as outlined in United States v. Norris, 217 F.3d 262, 270 (5th Cir. 2000). The Court found that the conditions of Poczynok’s testing were substantially similar to those of Medellin’s fall. Poczynok used the same model ladder as Medellin (equipped with Rock Locks 2.1), configured it as an extension ladder, and positioned it against a pitched roof above the driveway. The Court also highlighted that Kiska critically evaluated Poczynok’s tests and disregarded those he deemed inapplicable to Medellin’s accident. The distinctions raised by the Defendant were not significant enough to render Poczynok’s tests an unfair comparison to Medellin’s accident. The Court noted that any disparities between Medellin’s accident and Poczynok’s testing could be demonstrated through cross-examination. 

The Defendant argued that Kiska’s opinions on design defect should be excluded, contending they were unreliable and irrelevant.  Specifically, the Defendant asserted that Kiska failed to provide evidence or testing to demonstrate that his alternative design would have prevented Medellin’s accident.

In design defect claims, the Plaintiff is required to present a safer alternative design that “would have prevented or significantly reduced the risk of the Plaintiff’s personal injury  without substantially impairing the product’s utility”. While the alternative design must be tested before a jury can conclude it would prevent or reduce the risk of injury, it’s not mandatory for the Plaintiff to build and test a prototype. Testing “can be as simple as applying math and physics to establish the viability of a design,” as clarified in Sims v. Kia Motors of Am., Inc., 839 F.3d 393, 407 (5th Cir. 2016).

Kiska provided the opinion that the Rock Locks 2.1 were defective in design due to the aluminum barrel pins pivoting into place and the locks lacking contrasting color to signal incomplete insertion of the barrel pins. His alternative design suggested the use of steel barrel pins that move linearly/perpendicularly into place and are colored red. The Defendant contended that Kiska had not tested the proposed design, thus lacking evidence that it would have prevented or significantly reduced the risk of Medellin’s injury.

Kiska tested the alternative design by applying engineering principles and analyzing the functionality of the current and proposed designs as a professional engineer. In support of the steel barrel pin with perpendicular movement, Kiska compared the coefficient of friction between an aluminum barrel pin and a steel barrel pin. He pointed out that “aluminum barrel pins are undesirable because of the higher coefficient of friction that exists between sliding parts (aluminum on aluminum vs. aluminum on steel), which can adversely affect proper locking”. Kiska determined that the friction coefficient of the aluminum-to-aluminum interface would be approximately twice as great as aluminum-to-steel, making it more difficult for the locking pins to engage properly and, therefore, more likely to ‘falsely lock.’

Kiska had also proposed using barrel pins that approach the rung holes perpendicularly, similar to those utilized in version 3.0 of Defendant’s Rock Locks. Although Kiska did not take measurements of a ladder equipped with Rock Locks 3.0, he testified that the perpendicular design is “more forgiving all things being equal” and “more favorable in terms of properly engaging and not hanging up on the inner section swage and false locking”. Kiska explained that, based on the design’s operation, the angled or arcing approach of the ladder’s barrel pins necessitates a “more exacting alignment between the sections” to get the barrel pins to properly engage beyond a false lock. The Court concluded that Kiska should be permitted to testify about his proposed alternative design, and any weaknesses in his analysis could be addressed through cross-examination.

Regarding the red coloring on the barrel pin, the Defendant argued that Kiska did not test the proposed design, wasn’t a human factors expert, and did not cite any study, testing, or modeling to demonstrate that a colored barrel pin would reduce the risk of injury. However, Kiska, being an expert in the field, was familiar with the use of coloration for safety purposes. He expressed the opinion that “many manufacturers use creative coloring (particularly the color red) as a means to draw attention to locking components as a means to communicate to users that a safety problem may exist”. Kiska’s report included side-by-side photographs illustrating the visual differences in the ladder’s design and the alternative design. He noted that when the colored pin is completely inserted, the red color would not be visible to the user, indicating that the lock is properly engaged. Kiska also referred to one of Defendant’s prior ladder designs that used colored locks to signal improper engagement of the locking mechanism. The Court acknowledged the weaknesses pointed out by the Defendant but deemed the arguments insufficient to completely exclude Kiska as an expert. Any weaknesses could be addressed by the Defendant through cross-examination to present them to the jury.

The Defendant argued that Kiska’s opinions on manufacturing defects were irrelevant because Kiska had not demonstrated that: (1) the identified manufacturing defects existed when Medellin’s ladder left the manufacturer; and (2) the manufacturing defects caused Medellin’s accident.

In a manufacturing defect claim, the Plaintiff was required to prove, among other things, that a product was defective when it left the manufacturer and that the defect was a producing cause of the Plaintiff’s injuries.

Kiska’s report had identified two manufacturing defects: (1) the hardness of the ladder’s feet exceeded the product specification’s upper tolerance limit; and (2) the width of the ladder’s outer section assembly exceeded the product specification’s upper tolerance limit. The Defendant argued that Kiska had not demonstrated that Medellin’s ladder was defective when it left the manufacturer.

Kiska’s report stated that “Inspection of the subject ladder shows that it was not manufactured to specification”, and Medellin’s deposition testimony, which Kiska reviewed, tended to demonstrate that the ladder’s condition remained unchanged between its manufacturing and Medellin’s accident. For instance, Medellin mentioned purchasing her ladder in November 2017 and using it only twice before her accident occurred: once in 2017 and once in 2018. She stored the ladder in her garage in its most compact configuration—fully retracted on both sides and folded in half. No one else used the ladder, and it had not been used after Medellin’s accident. Kiska inspected Medellin’s ladder and found it to be in generally good condition. The Defendant did not challenge Medellin’s testimony regarding her storage or use of the ladder or provide evidence that the ladder’s condition changed between its manufacture and Medellin’s accident or between Medellin’s accident and Kiska’s inspection. Whether the identified manufacturing defects existed when the ladder left the factory was deemed a question for the jury.

Regarding the causal connection between the manufacturing defects and Medellin’s accident, Kiska explained that the hardness of the ladder’s feet exceeded the product specifications, and harder material provides less slip resistance. He opined that “The likelihood of bottom slip out of a ladder is greater when its feet are composed of a harder material. This was the case with Medellin’s ladder”. Kiska reviewed the ladder’s specifications, which required slip-resistant feet “with a ‘Shore A durometer of 80+1-2.’” Thus, the maximum durometer reading would be 82 Shore A, but Medellin’s ladder’s left foot measured 91-92 Shore A, while the right foot measured 92-93 Shore A. Kiska stated that the feet on Medellin’s ladder would not be expected to provide as much resistance to slipping out as feet within the proper specifications. Thus, Kiska tied the out-of-specification hardness of the ladder’s feet to its propensity to slide out from under the user.

Kiska had also determined that the outer assembly of Medellin’s ladder exceeded the product specification’s upper tolerance limit. He explained that the specification drawing set the ladder’s outer assembly width at 15.00 inches, +0.00/-0.06, meaning the width should not exceed 15.00 inches under any circumstances. Kiska measured Medellin’s ladder at various points and found that both extension sections exhibited widths greater than allowed by the manufacturing drawings. This increased clearance could allow for greater misalignment of the two sections and their mating parts. Kiska explained that while some clearance is necessary for sections to slide freely, excessive clearance increases the inner section’s ability to shift relative to the outer section, adversely affecting the alignment of the locking pins and exacerbating the ability of the pins to be directed into their respective rung holes.

Kiska had connected his measurements indicating the ladder was out of specification to the ladder’s tendency to become falsely locked. Consequently, Defendant’s motion to exclude Kiska as an expert was denied.

Defendant sought summary judgment, reiterating the same arguments presented in the motion to exclude Kiska’s opinions. Defendant contended that Medellin did not establish causation, failed to propose a safer alternative design, and could not link the manufacturing defects to her accident. The Court, having found Kiska’s opinions admissible, suggested that if Defendant contested the degree of slip resistance in Medellin’s ladder, it could address that issue during Kiska’s cross-examination. The Court recommended that the Defendant’s Motion for Summary Judgment be denied.

Therefore, Judge Peter Bray denied Defendant’s Motion to Exclude the Opinions of Stanley Kiska and also recommended the denial of Defendant’s Motion for Summary Judgment. The parties were granted fourteen days from the service of the Memorandum and Recommendation to submit written objections. Failure to file timely objections would result in the preclusion of appellate review for factual findings or legal conclusions, except for plain error.

On January 2, 2024, the Defendant filed four objections. Initially, the Defendant contested Judge Bray’s denial of their challenge to Kiska’s opinions regarding the “false lock” condition of the Plaintiff’s ladder. Subsequently, the Defendant objected to Judge Bray’s determination that Kiska’s opinions on design defects should be allowed as evidence. Additionally, the Defendant raised an objection to Judge Bray’s conclusion that Kiska’s opinions on manufacturing defects should be admitted. Finally, the Defendant opposed Judge Bray’s recommendation to deny their Motion for Summary Judgment.

Upon thorough de novo consideration of the objected portions of the Magistrate Judge’s Report and Recommendation (M&R) and a review of the remaining proposed findings, conclusions, and recommendations for plain error, the Court found no errors. Consequently, the Court accepted the M&R and adopted it as the opinion of the Court. The Defendant’s arguments were deemed insufficient to warrant reversal, as they were fully examined and failed to demonstrate a compelling reason for a different outcome.


The Court rendered the following decisions:

  1. Judge Bray’s Magistrate Judge’s Report and Recommendation (M&R) was fully accepted and adopted as the holding of the Court.
  2. The Defendant’s Motion to Exclude the Opinions of Stanley Kiska is denied.
  3. The Defendants’ Motion for Summary Judgment is also denied.

The Court has not arrived on an outcome for this case since the remaining issues involved in this case still await resolution.

Key Takeaways:

Stanley Kiska’s expert opinion regarding the “false lock” condition of Medellin’s ladder was accepted by the Court, asserting that the ladder could be falsely locked on the ground, raised into position for use, and partially climbed without the user detecting the false lock. Kiska based this conclusion on a comprehensive review of deposition testimonies, photographs, videos, ladder inspections, and testing conducted by another expert, Peter J. Poczynok, in a related case. Despite the Defendant’s objections to Kiska relying on Poczynok’s testing methodology, the Court noted that the Defendant strategically chose not to challenge Poczynok as an expert witness during the case and did not object to Kiska’s reliance on Poczynok’s testing.

Furthermore, the Defendant’s objections to the validity of Poczynok’s testing for comparison purposes were overruled by the Court, which deemed Poczynok’s testing substantially similar, with any disparities to be addressed during cross-examination. The Court also allowed Kiska to testify about design defects and propose an alternative design, emphasizing that testing could be as simple as applying math and physics. The Defendant’s objections to Kiska’s reliance on Poczynok’s testing for design defects were considered insufficient, and the Court permitted Kiska to present his expert opinions.

In addition, the Court addressed the Defendant’s objections to Kiska’s opinions on manufacturing defects, specifically challenging the lack of evidence demonstrating that the defects existed when Medellin’s ladder left the manufacturer and that they caused the accident. The Court found Kiska’s measurements and analysis adequate to present a question for the jury on these issues.

Overall, the Court deemed Kiska’s expert opinions admissible, rejecting the Defendant’s objections as lacking merit and providing a comprehensive analysis of the expert’s methodologies and conclusions in the case.

Case Caption: Medellin v. Wing Enters., Inc.

Docket Number: 4:21cv3582

Court: United States District Court, Texas Southern

Citation: 2023 U.S. Dist. LEXIS 232419

Order Date: December 17, 2023


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