--by Paul Cianciolo, FAA Safety Briefing
Understanding the basics of aircraft certification can help you make sound decisions affecting the airworthiness and operation of the aircraft you own or rent. To help explain this, let’s take a look at the FAA’s role in how aircraft are designed, produced, and maintained.
Type Certificates
A type certificate is a necessary step along the path to producing and selling aircraft to the public. It serves as FAA approval of an aircraft type design, which includes the aircraft’s airworthiness and operating limitations.
To obtain this certification, a company must show that the aircraft design complies with FAA standards. These standards lay the groundwork for safe handling qualities, structural integrity, systems reliability, and other characteristics that many of us take for granted in the aircraft we fly. One of the key ways a company shows compliance with the airworthiness standards is through testing, such as on-ground wing structural tests or inflight spin tests. The FAA’s role is to examine the type design, as well as oversee and verify the tests that demonstrate a product complies with FAA standards.
If you want to add new technology, modify, or change the design of a type-certificated aircraft, you need a supplemental type certificate (STC) issued. Obtaining an STC typically requires a great deal of work for both the applicant and the FAA, especially for new technology that has not previously been approved on a type-certificated aircraft. All of this work is for a good reason. When you carry out an approved modification on your aircraft, you expect it to be safe and compliant with appropriate airworthiness standards.
Once the FAA determines that the applicant has demonstrated compliance with the airworthiness standards, including any special conditions issued specifically for the project, the FAA issues an STC. The FAA can also issue special conditions when it determines that the airworthiness regulations do not contain adequate or appropriate safety standards because of a novel or unusual design feature, such as an inflatable airbag system on multiple-place and single-place side-facing seats (i.e., seats positioned in the airplane with the occupant facing 90 degrees to the direction of airplane travel).
Production Certificates
If a company wants to consistently reproduce a type-certificated aircraft that it manufactures for sale to the public, then the FAA must issue a production certificate. The intent of production certification is to ensure that each product conforms to its type design and is in a condition for safe operation. The FAA conducts ongoing audits and evaluations to make sure the company’s production system continues to meet standards.
A parts manufacturer approval (PMA) is a combined design and production approval for modification and replacement parts. It allows a manufacturer to produce and sell these parts for installation on type-certificated aircraft.
Airworthiness Certificates
During preflight, checking that the aircraft has an appropriate and current airworthiness certificate displayed onboard is the pilot’s responsibility. Many factors can affect the condition of the airworthiness certificate after issuance, and it is the pilot’s responsibility to determine that an aircraft is airworthy before flight. Two things you’ll want to verify is that an aircraft must always:
- conform to its type certificate along with any approved changes to the type design, and
- be in a condition for safe operation.
Not all airworthiness certificates are the same. Let’s have a look at the different kinds you may encounter.
There are two different classifications of FAA airworthiness certificates: standard airworthiness certificates (allowing seven categories of operation), and special airworthiness certificates (with eight specialized categories).
A standard airworthiness certificate (FAA form 8100-2 displayed in the aircraft) is the FAA’s official authorization allowing for the operation of type-certificated aircraft in the following categories: normal, utility, acrobatic, commuter, transport, manned free balloon, or a special class. The certificate remains valid as long as the aircraft meets its approved type design; is in a condition for safe operation; and maintenance, preventive maintenance, and alterations are performed in accordance with Title 14 Code of Federal Regulations (14 CFR) parts 21, 43, and 91.
A special airworthiness certificate (FAA Form 8130-7) is the FAA’s authorization for the operation of aircraft in specialized categories as outlined in 14 CFR section 21.175. These eight categories are: primary (e.g., personal use aircraft), restricted (e.g., agricultural, forest/wildlife conservation, aerial survey, or patrol), multiple (restricted plus one or more other categories except primary), limited, light-sport (e.g., for special light-sport aircraft made in accordance with consensus standards), experimental (e.g., research and development; crew training; exhibition; air racing; demonstrating compliance with regulations; operating amateur-built, primary kit-built, or experimental light-sport aircraft), special flight permit, and provisional. For more details about each of these categories, see go.usa.gov/xEGs2.
An experimental certificate for research and development, showing compliance with regulations, crew training, or market surveys is effective for one year after the date of issue or renewal unless the FAA prescribes a shorter period. The duration of an experimental certificate issued for operating amateur-built aircraft, exhibition, air-racing, operating primary kit-built aircraft, or operating light-sport aircraft is unlimited, unless the FAA establishes a specific period for good cause.
When it comes to determining if an aircraft is airworthy, the PIC is always the final decision-maker.
Safe design and construction are only part of the picture when it comes to safe aircraft. You can help keep your aircraft airworthy — safe and in conformance with its type design — by maintaining and operating it according to its airworthiness and operating limitations.
Repairs and Alterations
Two actions that can affect conformance with the type certificate of an aircraft are repairs and alterations, which are defined as follows:
A “repair” is an action taken to return an aircraft to its current type design, and therefore to an airworthy status. Typical repairs include replacing defective parts, such as a vacuum pump; or making approved sheet metal repairs, such as repairing damage from a bird or deer strike.
An “alteration” is any action that changes or modifies the original type design. For example, an alteration might involve installation of an engine or propeller not included in the type design.
When a repair or an alteration affects the aircraft’s weight and balance, structural strength, performance, powerplant operation, or flight characteristics or operations, it is deemed to be a “major” repair or alteration.
Anyone who performs required maintenance and inspections, preventative maintenance, repairs, or alterations must document their work. The pilot is responsible for ensuing repairs have been appropriately documented before operating the aircraft. You should be able to locate the entries for required maintenance, inspections, and preventive maintenance in the aircraft’s maintenance records. For anything that qualifies as a major repair or major alteration, the aircraft maintenance records require a completed FAA Form 337.
A field approval is one of the means used by the FAA to approve technical data used to accomplish a major repair or major alteration. It is an approval through an authorized FAA Aviation Safety Inspector (airworthiness) of technical data and/or installations used to accomplish a major repair or major alteration. This type of approval may be accomplished for one-time approval, and the inspector approves the repair or alteration by signing block 3 of FAA Form 337.
Return to the Sky
The FAA’s Aircraft Certification Service is responsible for overseeing the design, production, and original airworthiness certification of civil aircraft and related products. Maintenance personnel approve the aircraft for return to service, but it is the pilot-in-command (PIC) who actually returns the aircraft to service by flying it. When it comes to determining if an aircraft is airworthy, the PIC is always the final decision-maker.
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Paul Cianciolo is an associate editor and the social media lead for FAA Safety Briefing. He is a U.S. Air Force veteran, and a rated aircrew member and volunteer public affairs officer with Civil Air Patrol.