A three-engine cargo jet, full thrust, and one engine just tears away from the wing. That’s exactly what investigators now believe happened to UPS Flight 2976 in Louisville. Here’s how it works: every jet engine is held to the wing by a pylon — a metal structure packed with bolts, hydraulic lines, and sensors. If even one critical bolt cracks or a pylon fitting corrodes over time, it can trigger what engineers call “structural separation.” Once the engine comes off, the wing instantly loses both