In a multi-fatality products liability case arising from the crash of a de Havilland DHC-3 Otter aircraft in Alaska in 2013, a federal district court in Alaska excluded evidence from five other accidents and incidents to prove negligence, a design defect, or notice of a design defect after concluding that those accidents were not “substantially similar” to the Otter accident.

In In Re Crash of Aircraft N93PC on July 7, 2013, At Soldotna, Alaska, plaintiffs alleged that the aircraft's TPE 331-10R-511C turboshaft engine was not producing power when it crashed shortly after takeoff, because the engine's torsion shaft fractured and failed in flight.  Defendant Honeywell International (“Honeywell”) disputed that the torsion shaft failed in flight and moved in limine to exclude evidence of five other accidents or incidents about which plaintiffs' experts Colin Sommer and Arthur Coffman had testified.

The Court noted that “[o]ther-accident evidence to prove negligence, design defect, or notice of a defect is admissible on a showing of ‘substantial similarity' of the other accidents to the accident which is the subject of the litigation.”  The Court further noted that “‘[s]ubstantial similarity depends upon the underlying theory of the case.  Evidence proffered to illustrate the existence of a dangerous condition necessitates a high degree of similarity because it weighs directly on the ultimate issue to be decided by the jury.'”

In applying these rules, the Court emphasized that “[e]ven if the proponent establishes substantial similarity of circumstances, the trial court has discretion to determine the admissibility of such evidence and ‘must weigh the dangers of unfairness, confusion, and undue expenditure of time in the trial of collateral issues against the factors favoring admissibility.'”

In its detailed examination of the five other accidents and incidents and whether they were “substantially similar” to the Otter accident, the Court analyzed a number of facts and circumstances, including the following:  (1) whether the same model of Honeywell engine was involved; (2) whether the same model of torsion shaft was involved; (3) whether there were allegations of aircraft conditions that were different in each of the accidents and incidents; (4) the level of experience of the pilots in each accident or incident; (5) the phase of flight when the alleged torsion shaft failure occurred (i.e., on takeoff or during a different phase of flight); and (6) whether the aircraft involved was a single engine or multi-engine aircraft.

After performing this detailed analysis, the Court concluded that plaintiffs had not established “substantial similarity” and, therefore, evidence related to these five other accidents and incidents was excluded for the purpose of proving negligence, a design defect, or notice of a design defect with respect to the torsion shaft.  However, in rejecting a blanket exclusion of the evidence, the Court also noted that the substantial similarity requirement only applies if the evidence is being offered to prove negligence, design defect, or notice of a defect and, therefore, it still was possible (upon an appropriate showing at trial) that evidence related to these accidents and incidents might be relevant and could be admissible for another purpose.

This case illustrates the vital importance of developing an appropriate record to challenge attempts by plaintiffs to offer other accident or incident evidence to prove negligence, defect, or notice of a defect.  In Re Crash of Aircraft N93PC on July 7, 2013, At Soldotna, Alaska, 2021 U.S. Dist. LEXIS 108635 (D. Alaska Jun. 10, 2021).

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.