23.685—Control system details.
(a)
Each detail of each control system must be designed and installed to prevent jamming, chafing, and interference from cargo, passengers, loose objects, or the freezing of moisture.
(b)
There must be means in the cockpit to prevent the entry of foreign objects into places where they would jam the system.
(d)
Each element of the flight control system must have design features, or must be distinctively and permanently marked, to minimize the possibility of incorrect assembly that could result in malfunctioning of the control system.