How New Technology Takes Flight
Mark James and Steve Thompson
Reprinted with permission from FAA Aviation News
Have you ever wondered how new technology finds its way into general aviation aircraft? At the heart of innovation are companies and individuals who pour their hearts, minds, and finances into developing new or improved products. From advances in avionics to new ideas for propulsion, and everything in between, these pioneers research and develop innovative technologies that often make flying better, safer, or more affordable for the rest of us. Much of this innovation takes place at the grass-roots level of aviation in the United States—the amateur-built (or “homebuilt”) aircraft community. The federal aviation regulations governing this segment of flying create an environment where new ideas can be cultivated, developed, and refined relatively quickly.
What about type-certificated aircraft operating with a standard airworthiness certificate? What does it take to introduce new technology into these aircraft? The most common method is through issuance of a supplemental type certificate (STC). Obtaining an STC typically requires a great deal of work for both the applicant and the FAA, especially for new technology that has never before been approved on type-certificated aircraft. All this work is for a good reason. When you purchase and install an approved modification on your aircraft, you expect it to be safe and compliant with appropriate airworthiness standards.
Story of an STC
For a glimpse into the role FAA plays in facilitating the safe introduction of new technology into certificated aircraft, let’s take a look at airbags. A few years ago, a company applied for an STC to install airbags in a general aviation airplane. Although airbags have long been standard equipment in cars, this was the first application of airbags in a general aviation airplane.
The potential safety benefit of airbags was easy to recognize (see box); the challenge for the FAA was in determining appropriate certification standards. When small airplane airworthiness standards (Title 14 Code of Federal Regulations (14 CFR) part 23 and its predecessor Civil Air Regulations (CAR) 3) were written, the FAA did not envision airbag technology. So, the FAA had some homework to do.
Considering that 14 CFR part 23 doesn’t require airbags, you might wonder why the FAA would be concerned with standards for their installation. After all, having airbags would be better than not having those, right? That was actually one of the questions the FAA needed to have answered. Consider what would happen if an airbag inadvertently deployed during a critical phase of flight. Or, what if the airbag, which is built into the restraint itself, weakened the restraint below certification standards? Or, what if the airbag deployed in such a way that it injured the pilot or passenger? Or, how about this one—what if after an appropriate deployment during an accident, the airbag failed to deflate and impeded the occupants’ egress from the airplane? These and other considerations influenced the FAA’s determination of additional certification standards for the STC project.
In an aircraft certification project where new technology warrants the development of specific certification requirements, how does the FAA go about implementing those requirements? Amending the airworthiness standards (14 CFR part 23) is a significant undertaking, can take years to complete, and is only appropriate if the revised standards have wide application. Fortunately, the FAA has the ability to issue special conditions, which are regulations that apply to a particular aircraft design. The FAA issues 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.
A special condition is an important tool for the FAA because it provides a timely means for the agency to establish appropriate standards for the introduction of novel, innovative technology into the world of type-certificated aircraft. FAA issued special conditions for the airbag STC to address two primary considerations. One, the airbags perform properly under foreseeable operating conditions. And two the airbags not perform in a manner or at such times that would impede the pilot’s ability to maintain control of the airplane or constitute a hazard to the airplane or occupants.
Once the FAA determined that the applicant had demonstrated compliance with the airworthiness standards, including the special conditions issued specifically for this project, the FAA issued an STC. This STC, which incorporated by reference the original TC, approved not only the airbag modification, but also how that modification affected the original design. If you would like to learn more about the airbag STC and STCs in general, go to www.faa.gov/aircraft/air_cert/design_approvals/stc.
Mark James and Steve Thompson are both aerospace engineers at the FAA’s Small Airplane Directorate in Kansas City, Missouri.