Wheel chocks work by being snugged up against tires to prevent them—and the aircraft—from moving. Legacy chocks made of wood sometimes fail for a variety of reasons, Troidl said. “Wood by nature can vary in weight and density, so some may float away in a strong rain; others may get waterlogged and become very heavy or get stuck under a tire. Wood can easily warp or splinter off pieces that could be sucked into the aircraft engine on start up.”| udayton.edu