1. Understanding the Faa'S Role in Aerospace Regulation
The Federal Aviation Administration (FAA), operating under the U.S. Department of Transportation, sets and enforces airworthiness standards for civil aircraft designed, manufactured, and operated in the United States. Its regulatory reach covers design approval, production oversight, and maintenance requirements across all civil aircraft categories.
The Faa'S Authority and Jurisdiction
FAA jurisdiction applies to domestic manufacturers and to foreign manufacturers seeking U.S. .arket access. Bilateral aviation safety agreements with partner authorities can reduce redundant testing, but full FAA compliance remains the baseline for any aircraft entering U.S. .ervice. Our Aerospace and Defense practice works with manufacturers navigating these requirements at every stage.
Why Faa Compliance Matters for Your Business
A compliance failure can lead to aircraft groundings, stop sale orders, certificate revocations, and civil penalties that accumulate daily. For defense contractors, FAA airworthiness standards often overlap with military acceptance criteria, making federal compliance a prerequisite for program participation.
2. Aircraft Certification: the Pathway to Market
Getting an aircraft to market requires two separate approvals: one for the design and one for the production process. Which certification type applies depends on whether the manufacturer is introducing a new design or modifying an existing one.
Type Certification Vs. Supplemental Type Certificates
A Type Certificate (TC) is the FAA's formal approval of a new aircraft, engine, or propeller design. No manufacturer may sell a new aircraft model in the United States without one.
A Supplemental Type Certificate (STC) authorizes a specific modification to an already certificated aircraft, such as adding new avionics or retrofitting a structural component. An STC supplements the original TC rather than replacing it, and both must remain valid for the modified aircraft to operate. The FAA's classification of a proposed change as major or minor determines which path applies.
The Application Process and Timeline
A TC application goes to the FAA Aircraft Certification Office (ACO) with jurisdiction over the applicant's location. The process moves through the following stages:
- Establishing the certification basis and applicable regulations
- An issue paper process to resolve novel or unusual design features
- Type Inspection Authorization for prototype testing
- Conformity inspections and flight testing under an approved test plan
- Final airworthiness determination and certificate issuance
Part 23 aircraft typically complete the process in two to four years. Transport category Part 25 programs run considerably longer, particularly for designs with novel technologies. Applicants without a structured compliance plan before the application is filed tend to experience the largest delays.
3. Part 23 and Part 25: Small Vs. Large Aircraft Standards
The applicable airworthiness standard turns on aircraft size and category. Selecting the wrong framework at the start of a program can require costly redesign, so getting this determination right matters early.
| Part 23 | Part 25 | |
| Applies to | ≤19 seats, ≤19,000 lbs MTOW | Transport category aircraft |
| Regulatory approach | Performance-based (post-2017 rewrite) | Prescriptive, detailed testing required |
| Compliance flexibility | Higher; alternative means accepted | Lower; extensive supporting data required |
Applies to
- Part 23≤19 seats, ≤19,000 lbs MTOW
- Part 25Transport category aircraft
Regulatory approach
- Part 23Performance-based (post-2017 rewrite)
- Part 25Prescriptive, detailed testing required
Compliance flexibility
- Part 23Higher; alternative means accepted
- Part 25Lower; extensive supporting data required
Part 23 Regulations for Smaller Aircraft
The 2017 rewrite of Part 23 replaced prescriptive rules with performance based safety objectives. Manufacturers can now propose alternative means of compliance rather than following a fixed method. This creates real design flexibility, but requires early agreement with the FAA on a compliance checklist that documents how the manufacturer plans to meet each safety objective.
Part 25 Requirements for Large Transport Aircraft
Part 25 sets detailed requirements across structural integrity, systems safety, flammability, emergency evacuation, and flight performance. Dedicated FAA flight test teams and formal test plans are standard. Working with aviation and aerospace attorneys who know Part 25 can prevent the late stage compliance gaps that extend programs by months.
4. Manufacturing and Production Compliance
A Type Certificate covers the design. A Production Certificate (PC) is a separate approval authorizing a manufacturer to build aircraft that conform to that design. Many companies underestimate the scope of the PC process, which requires a fully documented quality system before the FAA will issue the certificate.
Production Certificate Requirements
To obtain a PC, the manufacturer must demonstrate that its quality system consistently produces conforming articles. The FAA evaluates:
- Quality management procedures and documentation
- Inspection and test capability at each production stage
- Supplier oversight records and an approved supplier list
- Conformity inspection records and corrective action processes
Supplier Obligations and Due Diligence
PC holders are responsible for their suppliers' compliance, not just their own. Supplier failures that allowed nonconforming parts to reach certificated aircraft in service have triggered FAA enforcement actions. For companies involved in aircraft transactions where existing production approvals transfer to a buyer, reviewing the seller's PC status and supplier oversight records is a necessary step in due diligence.
5. Airworthiness Directives and Ongoing Compliance
Certification and production approval do not end a manufacturer's regulatory obligations. Once aircraft enter service, the FAA expects type certificate holders to monitor safety performance and participate actively in correcting problems that surface.
What Airworthiness Directives Are
An Airworthiness Directive (AD) is a legally enforceable FAA regulation that requires a specific corrective action for an unsafe condition. The FAA issues ADs under 49 U.S.C. § 44701; they may require inspection, modification, part replacement, or operational limitation. Compliance is mandatory for all operators and owners of affected aircraft within the specified time.
When a TC holder identifies a safety concern, it typically coordinates with the FAA to develop the corrective action. The FAA then formalizes that action as an AD. Manufacturers that fail to report known unsafe conditions face exposure under 14 CFR Part 21, and intentional concealment can result in criminal referral.
Reporting Requirements and Penalties
Under 14 CFR § 21.3, holders of type certificates, production certificates, and supplemental type certificates must report any failure, malfunction, or defect that has resulted in or could result in an unsafe condition. This obligation applies before an incident occurs.
Civil penalties under 49 U.S.C. § 46301 can accrue per day of continued noncompliance. The FAA may also revoke, suspend, or modify certificates. Where a compliance failure contributes to an accident, product liability exposure in civil litigation follows independently of the FAA enforcement action.
6. Frequently Asked Questions
What is the difference between a Type Certificate and a Production Certificate?
A TC approves the aircraft design. A PC authorizes a manufacturer to produce articles conforming to that design. Both must be in place before a manufacturer can legally produce and sell an aircraft in the United States.
Does Part 23 or Part 25 apply to my aircraft?
Part 23 covers aircraft with a maximum takeoff weight of 19,000 pounds or less and 19 or fewer passenger seats. Part 25 covers transport category aircraft. The FAA makes the final classification based on design characteristics and intended operation.
What happens if a manufacturer misses an AD compliance deadline?
Operating an aircraft out of AD compliance violates federal regulations and can result in civil penalties, certificate action, and mandatory grounding of the aircraft until the operator achieves full compliance.
30 Mar, 2026
