Usually, the engines are mounted on the wing at three points (usually two forward and one aft) with shear (or fuse) pins, with one or two bolts at each point. The DC-10, for example 6 (later 8 pins), while the 747-200 has 6.

While it may sound terrifying, a Boeing 747 engine is typically held onto the pylon by as few as three to four massive "fuse pins" or bolts. These aren't standard hardware store bolts; they are high-precision, multi-inch thick titanium or high-strength steel alloy pins engineered to withstand hundreds of thousands of pounds of thrust. Interestingly, they are designed as "mechanical fuses"—meaning they are engineered to shear (break) under extreme, specific loads. This is a safety feature: in the event of a catastrophic engine failure or a severe crash, the bolts are designed to fail so the engine can drop away cleanly from the wing rather than tearing the entire wing off the aircraft. In 2026, these mounts are subject to the most rigorous inspection cycles in aviation, ensuring that despite the "small" number of fasteners, the connection is one of the most over-engineered and secure joints in modern machinery.