Leonardo da Vinci’s pyramid-shaped emergency aircraft design was a parachute.
In a manuscript now associated with the Codex Atlanticus, Leonardo described a canopy made from linen held open by a framework of poles. He reasoned that a person could descend safely from a height under the canopy. His design was approximately twelve braccia wide and twelve braccia deep, with a matching height; the historical braccio was a Renaissance unit whose exact modern length varied.
Leonardo’s parachute was not a modern fabric parachute. It was a rigid or semi-rigid pyramid-like structure, and there is no firm evidence that he tested it. In 2000, British adventurer Adrian Nicholas built and tested a replica, reporting that it descended successfully, although he used a modern backup parachute for safety.
The parachute concept is distinct from Leonardo’s flying machines. It was intended to slow a fall, not provide powered or sustained flight. The design shows Leonardo applying geometry and air resistance to a practical safety problem.