New amendments to Part 36 require a minimum 3 dB–noise reduction for small single-engine propeller aircraft– including turboprops–weighing more than 3,307 pounds, for which an original type certificate is applied after February 3. As proposed, the new standard would have also applied to new STCs. But after weighing comments from the industry, the FAA changed the final rule so it would not apply to STCs for airplanes already type certified “even if it results in an acoustical change.