Why can airplanes be as strong as black boxes?
They could, but then they would be too heavy to get off the ground. The so-called black boxes house the flight data recorders and cockpit voice recorders that investigators use to help them determine the cause of a crash. They are made of steel so they can survive the impact of a crash as well as fire and immersion in water. Steel is much too heavy for an airplane, which mostly is made of aluminum and various lightweight composite materials. Still, airplanes are designed to be strong as well as lightweight. In many of the accidents that have occurred, the airframe has remained largely intact following impact with the ground.
