Aviation Senior Citizens. Just as humans need more and different care as they age, so do older aircraft such as these two still popular models, a Piper Comanche and a Beech Bonanza, both well on the high side of 40. Photo by Dave Higdon

Some members of the general aviation (GA) community and GA aviation industries are angry over changes in FAA policy that make it more difficult to obtain field approvals (FAA Form 337) for aircraft modifications. Because of the current policy, which was instituted in 2004, some kinds of modifications that used to be granted as field approvals now require an STC (supplemental type certificate).

The 337/STC policy was the topic of a sometimes-heated discussion at Wednesday’s annual "Type Club & Aging GA Aircraft Issues" meeting. Held each year at AirVenture, the meeting brings together leaders from the agency and the industry to identify problems and seek creative solutions.

Both field approvals accomplished via FAA Form 337 and STCs provide agency approval for changes to an aircraft not conforming to its original type certificate or to an existing STC for that airplane. Typical field approvals or STCs might cover aftermarket or non-aviation replacement parts, radios, instruments, engines, propellers, STOL kits, or airframe modifications. A field approval applies to a single aircraft. As the complexity of the modification increases, the policy requires an STC rather than a 337. An STC applies to all aircraft of a single aircraft type—all Cessna 172Bs, for example. A "middle ground" option—a "One-Time STC"—applies, like a 337, to only one aircraft. The process is more rigorous than a 337 but simpler than a full STC. Local FAA representatives can grant field approvals. Obtaining an STC or one-time STC is a more complicated approval process handled through FAA regional offices.

At Wednesday’s meeting, aircraft restorers and vintage type-club officers argued that the 2004 change in FAA policy has effectively eliminated field approvals by "forcing everyone into the STC process," even for items previously receiving Form 337 field approvals. They further argued that long delays in granting STCs have effectively eliminated the STC option as well, forcing owners of aging aircraft to forego proper maintenance or use unapproved parts.

FAA officials responded that the policy change was necessary. "Some of the 337 field approvals [that were granted before the policy change] went well beyond what the FAA inspectors should have done or were qualified to do," said Jim Ballough, FAA Flight Standards director. "A lot of people out there do not understand the 337/STC processes," he added, and that led to what the FAA feels were inappropriate field approvals.

If the change in policy and the resulting increase in STC requests have caused delays in STC approvals, that’s a problem, Ballough said. "We’re going to work it out." He added, "If there are other issues that need to be resolved, work through EAA, communicate your concern to them, and we’ll take a look at it."

"A lot of this has to do with education," said H.G. Frautschy, executive director of EAA’s Vintage Aircraft Association and editor of Vintage Airplane magazine. "We’re working with the FAA’s John Colomy on a series of articles that will appear in Vintage Airplane magazine this fall, explaining the 337 and STC approval process."

After several people at the meeting complained that the FAA’s policy change was unreasonable and unnecessary, John Hickey, FAA’s director of aircraft certification services, replied, "We didn’t do this in a vacuum; we held meetings and listened to people all over the country, including four meetings in Alaska where the issue was most contentious." But, he added, the FAA has a responsibility to uphold aircraft standards and ensure aircraft safety, "and some of the existing 337s fell way outside the standards" for field approvals.

With tensions apparently rising on both sides of the issue, Kim Smith, of the FAA Small Airplane Directorate, appealed to the group, "Please," she said, "while we disagree on some things, let’s not lose the energy or the collaborative spirit we started with here." Alluding to issues that remain contentious and unresolved, she told the group that solutions will be found. "We [FAA and the industry] can do it separately or we can do it together. You’ll be happier if we do it together."

"The 337 policy has changed," said Earl Lawrence, EAA vice president of industry and regulatory affairs. "We are going to have to do the engineering data when we make major changes in an aircraft. Blaming the FAA is not the answer. The agency is really bending over backwards to work with us on this."

"If this [policy] is the issue," Lawrence told the industry leaders, "let’s get together on it, get our act together, and then work with the FAA."