14 CFR § 23.2250

The applicant must design each part, article, and assembly for the expected operating conditions of the airplane.

Design data must adequately define the part, article, or assembly configuration, its design features, and any materials and processes used.

The applicant must determine the suitability of each design detail and part having an important bearing on safety in operations.

The control system must be free from jamming, excessive friction, and excessive deflection when the airplane is subjected to expected limit airloads.

Doors, canopies, and exits must be protected against inadvertent opening in flight, unless shown to create no hazard when opened in flight.