Under which CFR Part is the Piper PA-28-235 certified along with additional requirements?

The Piper PA-28-235 is certified under 14 CFR Part 23, which governs the airworthiness standards for normal, utility, acrobatic, and commuter category airplanes. Part 23 establishes criteria for design, performance, and safety to ensure that these aircraft are suitable for their intended roles. This part covers a wide range of parameters including structural integrity, flight control systems, and emergency procedures, specifically tailored for smaller general aviation aircraft like the Piper PA-28 series.

Part 25, in contrast, applies to large transport category airplanes, which is not applicable to the PA-28-235. Part 21 addresses the certification processes for aircraft and their components but does not specifically establish airworthiness standards. Lastly, Part 29 pertains to rotorcraft, which is irrelevant to the PA-28-235 since it is a fixed-wing aircraft. Therefore, the correct framework for certifying the Piper PA-28-235 along with its operational requirements is found in Part 23.