FAA Certification: A Practical Guide for Aerospace Manufacturers

Prime Propulsion
20 hours ago
7 min read

FAA certification is the common thread running through nearly every engineering decision an aerospace manufacturer makes. Whether you're producing a replacement part, modifying an aircraft, approving a repair process, or qualifying a test cell — you're navigating the FAA certification system. Understanding how that system works, and which approval path applies to your specific situation, is the difference between a program that moves efficiently and one that stalls in a comment cycle it didn't see coming.

This post provides a working overview of FAA certification — what it covers, how the different approval paths relate to each other, and what it takes to move through the process cleanly. For manufacturers and MRO operators new to the certification process, it's the starting point. For those with existing programs, it's a useful framework for evaluating where your current approach is working and where it may be creating risk.

What FAA Certification Covers

The FAA's certification authority covers the full lifecycle of civil aviation products in the United States — the design, production, airworthiness approval, and ongoing maintenance of aircraft, engines, propellers, and their components. For manufacturers, certification is the mechanism by which the FAA authorizes you to produce, modify, or approve products for installation on certificated aircraft.

That authority flows through several different approval types, each governed by its own regulatory framework within Title 14 of the Code of Federal Regulations. The four most relevant for propulsion and component manufacturers are:

Type Certificate (TC) — the foundational design approval for a new aircraft, engine, or propeller. Held by the original equipment manufacturer. All downstream approvals reference the TC.

Supplemental Type Certificate (STC) — an FAA approval for a modification to a type-certificated product. If you're changing a design that someone else originally certificated, you're working in STC territory. Governed by 14 CFR Part 21, Subpart E.

Parts Manufacturer Approval (PMA) — an FAA approval that authorizes a manufacturer other than the TC holder to produce replacement or modification parts for certificated aircraft. Governed by 14 CFR Part 21, Subpart K. Grants combined design, production, and installation authority in a single document.

Repair Specification — an FAA-approved document that defines the methodology for performing a major repair on a specific aircraft component. Governed by 14 CFR Part 43. Reusable across multiple articles of the same part number without requiring new approval each time.

Test cell correlation sits alongside these approvals — not a product certification itself, but the FAA approval that authorizes a maintenance facility's test cell to produce airworthiness-quality performance data under 14 CFR 43.2.

Understanding which of these applies to your program is the first decision in every certification engagement. Getting it wrong — pursuing a PMA when an STC is required, or treating a major repair as a minor one — creates rework that is far more expensive than getting the determination right at the outset.

How the FAA Certification System Is Structured

The FAA doesn't review every certification submission directly. Instead, it delegates engineering authority to Designated Engineering Representatives (DERs) and Organization Designation Authorizations (ODAs) — qualified individuals and organizations who review and approve technical data on the FAA's behalf.

A DER holds specific authority delegated by the FAA under 14 CFR Part 183. That authority is documented in a Certification Letter of Authorization (CLOA) that defines exactly which regulations the DER is authorized to make findings against. A DER with Part 33 delegations can approve engineering data for aircraft engine programs. A DER with Part 23 and Part 25 delegations can approve data for fuel system and powerplant installation programs on fixed-wing aircraft. A DER with Part 27 and Part 29 delegations covers rotorcraft powerplant integration.

The DER's role in the certification process is to review your engineering data package, evaluate it against the applicable airworthiness standards, and issue a Form 8110-3 — the engineering finding that constitutes FAA approval of that data. Without a DER finding, your submission to the FAA Aircraft Certification Office (ACO) is incomplete regardless of how strong the underlying engineering is.

This structure has an important practical implication: the DER is not just a signature at the end of the process. A DER engaged early — during compliance planning, before data development begins — shapes the package in a way that minimizes FAA comment cycles. A DER brought in at the end to sign off on work that was already done without their input generates comments, rework, and timeline slippage that was entirely preventable.

The FAA Certification Process: What It Actually Looks Like

Regardless of approval type, FAA certification follows a consistent general sequence. The specific requirements within each step vary by regulatory path, but the overall structure is the same.

Step 1: Determine the certification basis. Identify which regulations apply to your product or modification, and which edition of those regulations governs your program. For most propulsion programs this means Part 33 for engine-related work, Part 23 or Part 25 for fixed-wing powerplant installations, and Part 27 or Part 29 for rotorcraft powerplant integration.

Step 2: Establish the compliance plan. Document how you intend to show compliance with each applicable regulation — through analysis, test, inspection, similarity, or a combination. For STC programs this becomes the Project Specific Certification Plan (PSCP), agreed upon with the FAA ACO before data development begins. For PMA programs it's the compliance matrix under 14 CFR §21.303 and AC 21.303-4.

Step 3: Develop the engineering data package. Generate the drawings, analyses, test plans, test reports, and substantiation data that demonstrate compliance with the certification basis. This is the technical core of the program. Package quality here determines how smoothly FAA review goes.

Step 4: DER review and approval. Submit the data package to your DER for engineering review. The DER evaluates whether the data adequately demonstrates compliance, identifies gaps or weaknesses, and issues Form 8110-3 findings for each area of compliance. Packages that haven't been reviewed by the DER before FAA submission almost always generate comment cycles.

Step 5: FAA submission and ACO coordination. Submit the complete package — including DER findings — to the appropriate FAA Aircraft Certification Office. The ACO reviews for administrative completeness and technical adequacy. Well-organized, complete packages with strong DER findings move through ACO review with minimal comments.

Step 6: Approval issuance. For PMA programs, the FAA issues the PMA document. For STC programs, the FAA issues the Supplemental Type Certificate. For repair specifications, the FAA issues the approved repair specification document.

Which FAA Certification Path Is Right for Your Program

Pursue a PMA if you're producing a replacement or modification part for a certificated aircraft or engine and you are not the TC holder. PMA gives you design, production, and installation authority in one document and is the primary mechanism for aftermarket parts manufacturers and MRO operators converting proprietary repair processes into marketable products.

Pursue an STC if you're making a design change to a type-certificated product — an engine modification, a fuel system redesign, a new propulsion system integration. The STC holder owns the approved design change and can authorize others to install it.

Pursue a repair specification if your facility has developed a proprietary repair methodology for a specific component and performs that repair repeatedly. The repair specification authorizes your facility to perform the repair without obtaining a new one-time Form 337 approval each time.

Pursue test cell correlation if your MRO facility overhauls and tests certificated engines. The correlation package demonstrates that your test cell produces data equivalent to the OEM reference cell, satisfying the 14 CFR 43.2 requirement before engines are returned to service.

In some programs, multiple approvals apply simultaneously — an MRO that develops a proprietary repair, gets it approved as a repair specification, and then converts it to a PMA is navigating all three in sequence. A defense contractor integrating a commercial turbofan into a military platform may be pursuing an STC while also needing PMA support for certain components.

What Determines How Long FAA Certification Takes

The most common question we get from new clients is how long the process will take. The honest answer is that timeline is almost entirely determined by three factors: submission quality, DER engagement timing, and FAA workload.

Submission quality is the factor you control most directly. Packages that are complete, well-organized, and address every applicable regulatory requirement before they reach the FAA ACO move quickly. Packages with gaps, missing DER findings, or inadequate substantiation generate comment cycles — each of which adds 4 to 8 weeks minimum to the program.

DER engagement timing is the factor most manufacturers underestimate. Bringing a DER in after the engineering is done to review and approve it is not the same as working with a DER from the start of the program. Early DER involvement shapes the compliance approach, identifies issues before they become comments, and produces a package that the DER has already evaluated before it reaches the FAA.

FAA workload is the factor you control least. ACO review timelines vary by office and by program volume. The best mitigation is submitting a package that requires minimal FAA interaction — a complete, well-organized submission that gives the ACO reviewer everything they need without follow-up requests.

The Role of Prime Propulsion in FAA Certification

Prime Propulsion is a DER-led FAA certification consultancy. Our founder holds active FAA delegations in Parts 23, 25, 27, 29, and 33 — covering the full range of fixed-wing and rotorcraft powerplant certification — and brings firsthand experience from Pratt & Whitney, the FAA, and the U.S. Air Force as a propulsion Subject Matter Expert on an ACAT 1D major defense acquisition program.

Every engagement is led by the DER directly. That means the engineer reviewing your compliance approach, developing your data package, and issuing your Form 8110-3 findings is the same person you speak with throughout the program. No project managers in between. No handoff queues.

If you're evaluating which FAA certification path applies to your program, or if you have an existing program that has stalled in the review process, contact us for a free 30-minute consultation. We'll give you a direct assessment of your options before you commit to anything.

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