
The Power of Testing and Video Evidence: Lessons from an Aerial Lift Tragedy
In this podcast episode, hosted by David Smith of Alpine Engineering & Design , the topic of discussion revolves around the effective use of testing and videos in evaluating legal cases and forming expert opinions. To illustrate this point, the host shares a tragic story involving a teacher who was conducting an aerial lift science project.
The project involved students from several grades who were tasked with building a contraption to protect an egg from breaking when dropped from a certain height. An aerial lift was arranged to drop the contraptions from a height of about 50 feet, with approximately 600 students watching the event. However, during a 360-degree turn around the truck to showcase the school’s aerial lift, a catastrophic failure occurred. The basket, still 30 feet in the air, came crashing down, resulting in the death of the operator and critical injuries to the teacher.
Upon inspection, it was discovered that several balls in the turntable of the aerial lift had come loose. The lift consisted of a stationary truck frame called a pedestal, on top of which was a rotating ring known as the slewing ring. The part above the slewing ring moved while the part bolted to the pedestal remained stationary. In this case, 9 of the 20 balls securing the stationary part had fallen out intact, and the remaining 11 were broken and fractured, leading to the catastrophic failure.
Different opinions emerged regarding how the balls became loose and why they were not checked before the incident. The hypothesis put forth was that the movement of the aerial lift, specifically the basket and arms, exerted force on the balls, causing insufficiently tight balls to work themselves out. To support this expert opinion, tests were conducted using a simulated contraption that mimicked the movement of the aerial lift. In a video, the contraption demonstrated how the balls started to work themselves out within a few cycles of movement, providing clear evidence of the cause of the incident.
The importance of video proof and thorough testing is emphasized throughout the episode. It is noted that relying solely on expert statements can be insufficient, and visual verification through videos can strengthen the argument. The tragic incident serves as a reminder of the necessity of conducting comprehensive testing and utilizing video evidence in legal cases to prevent unnecessary accidents and ensure accountability.
Overall, the podcast episode highlights the role of an aerial lift expert witness in analyzing accidents, forming expert opinions, and presenting compelling evidence through testing and videos. It underscores the importance of thorough investigation and the value of visual proof in legal proceedings.