The Engine & Propeller Directorate (E&PD), located in Burlington, Massachusetts, is responsible for original type certification or changes to approved designs of aircraft engines and propellers in addition to Technical Standard Order (TSO) approvals of auxiliary power units (APU).
We are responsible for developing rules, policy, and guidance for these products, and assureing standardization across all FAA Aircraft Certification Offices that perform certification work on these products. The E&PD Standards Staff (PDF) is the working element of the E&PD that directly carries out these functions.
The Engine Certification Office (ECO) and each Aircraft Certification Office (ACO) that performs certification work is accountable for planning, directing, and controlling engine and propeller type certification programs in addition to TSO approvals of auxiliary power units. Both the ECO's and ACO's primary responsibilities are to find compliance to the applicable Airworthiness Standards (i.e. 14 CFR parts 33 and 35 and TSO C77B) and assure continued airworthiness of these products, once in service.
The Manufacturing Inspection Office (MIO) is responsible for assuring aviation parts are manufactured to approved standards and issuing production certificates to manufacturers in accordance to the requirements of 14 CFR part 21.