On April 28, 1988, the forward upper fuselage of an Aloha Airlines Boeing 737 separated during an interisland flight, leaving a gaping hole in the passenger cabin. In spite of an 18-foot-long gap in the upper fuselage, the airplane landed safely. Inspections of the fuselage showed that the cause was related to fatigue cracks and corrosion. Following this incident, the Aviation Safety Research Act of 1988 and the Aging Aircraft Safety Act of 1991 were passed. These two acts addressed Transport category airplanes, and resulted in increased inspections and the implementation of new inspection techniques to ensure continued airworthiness of those aircraft. Are general aviation aircraft subject to the same aging process? Will general aviation aircraft start coming apart in the sky anytime soon?
Beginning the process
In January, the Small Airplane Directorate of the FAA hosted a General Aviation Continuing Airworthiness Summit in Kansas City, Missouri. Attendees included the FAA, aircraft owners and operators, and representatives of the industry including AOPA. The goal of this summit was to start an ongoing dialogue between aircraft users and the FAA to see if there is an aging-aircraft problem in general aviation and, if there is, how to cooperatively develop a plan of action to ensure continued safety and airworthiness of general aviation airplanes into the twenty-first century.
The three-day summit opened the door between the FAA and the general aviation industry to determine the main areas of concern. The results indicated that the FAA and the industry are both frustrated by—and concerned about—the lack of any reliable process to enhance communication, conformity, and information sharing. Major areas of concern included service difficulty reporting, the air worthiness process, Form 337 and field approvals, education of the FAA, data availability, maintenance, exploring the possibility of formulation and use of a historical aircraft category, and easing the approval of safety improvements—in other words, how to streamline existing FAA programs, and to create a clearinghouse for safety and maintenance data.
The fact that the FAA invited the industry and users to this conference to help formulate plans for future airworthiness is seen by the general aviation community as a giant step in the right direction. During a recent interview, Mike Gallagher of the Aircraft Certification Service in the Small Airplane Directorate said that one of the reasons for the summit is that the general aviation fleet is aging. The average age of a general aviation airplane is thought to be approximately 30 years.
Cooperation in the AD process
According to the wrap-up report from the summit, the Small Airplane Directorate is coordinating a cooperative process that takes a proactive approach to ADs. While this process is in place to some degree with the present notice of proposed rulemaking (NPRM) process, the FAA seems to be saying that cooperation between experts in the industry and the FAA before the AD is written will create better AD notes. This certainly bodes well for general aviation airplane owners and operators, who have seen some ADs issued in the past that defy logic. For example, in 1999 an AD was issued saying that when the fuel selector in certain Beechcraft airplanes was in between detented positions, with the pointer end between these positions, fuel wouldn’t flow. Apparently this AD was laughed out of existence, because it was later rescinded. In some cases it has appeared that the FAA has used failures that most experts think can be directly traced to poor maintenance to attempt to implement expensive wide-ranging redesigns of complete systems. The facts surrounding AD 2000-01-16, addressing twin-engine turbocharged Cessna 300- and 400-series’ exhaust systems, show how the involvement of owners and operators—and in this case owner organizations—can produce positive results during AD issuance.
The turbocharged twin Cessna exhaust AD
Because of a number of fatal accidents in 300- and 400-series Cessna turbocharged twins that involved exhaust systems failure, the FAA notified certain owners’ groups that there was going to be a rewrite of an existing AD. The AD had already been amended five times. This is in spite of the fact that an AD already existed and had been in place for 20 years. The Cessna Pilots Association, in Santa Maria, California, and AOPA spearheaded an effort to help—and in some cases force—the FAA to rethink the 20-year-old AD. The FAA eventually issued a directive that was much less onerous than the original proposal. This effort saved twin Cessna owners thousands of dollars. The value of including technically based owners’ groups in the AD process was proven in this example. A few FAA aircraft certification offices (ACOs) have been seeking owners’ group input related to AD issuance for years. The FAA seems to have recognized that the best source of information concerning maintenance, repair, and safety for many older airplanes is owners’ groups. This is especially true of aircraft that are orphaned; that is, the manufacturer is defunct and the holder of the type certificate is unknown. The summit also proposed to study the possibility of formation of an owner-maintained category of aircraft, in which the owner would be responsible for the aircraft maintenance.
Canada’s owner-maintained aircraft system
On April 17, 2000, Art Laflamme, Transport Canada’s director general of aviation, signed an act that created a separate category of certified aircraft that allows owners to take complete responsibility for the maintenance of certain older airplanes. The airplane owner can elect to give up his Normal category airworthiness certificate and replace it with an Owner Maintained certificate. While complete details were not available at press time, rough guidelines indicate that airplanes with up to 200 horsepower, with fixed landing gear, fixed-pitch prop, and with no more than four seats may be eligible for conversion to this category. Gallagher mentioned that this program has some appeal to the FAA.
Can an airframe have too many hours?
A great many general aviation pilots view an airframe with more than 5,000 flight hours with suspicion, yet there is a lot of evidence that a well-maintained and structurally upgraded airframe will not suffer an appreciable loss of airframe strength. Pat Hawk, the director of maintenance for Flight Express in Orlando, Florida, which operates more than 60 Cessna 210s and more than 30 Beechcraft Barons, says that he has six 210s with more than 22,000 airframe hours and another bunch with 13,000 to 14,000 hours. Hawk has asked Cessna if there’s a service life on the airframe but hasn’t been able to find anyone willing to put a figure down on paper.
Does that mean that the airplanes designed before the implementation of more modern certification standards were designed with an infinite service life? The answer seems to be partially explained in the regulations that were in place when almost all general aviation airplanes were certified. Civil Aviation Regulation 3 didn’t require any design life specifications for certification. FAR parts 23 and 25, the certification regulations used for new airplanes today, require manufacturers to specify the service life of certain components. For instance, the Piper Malibu PA–46-310, certified under Part 23, has a fuselage time-in-service limit of 10,145 hours. The wing time-in-service limit is 15,530 hours. Does this mean that the airplanes designed before design limits were required are not as safe as the airplanes designed under the life limit-specific regulations? There’s no indication that this is true based upon the conclusions in accident reports. But there are shortcomings in the present data-gathering system that both the FAA and the industry recognize.
According to one airframe engineer, there is always an additional safety factor designed into airframes—so that even if an airframe exceeded its design life by a factor of 10, the loss of strength in the aluminum would not be enough to exceed the design-load factors. In other words, if an airplane designer selected a design life of 10,000 hours and the airplane were to fly to 100,000 hours, the airframe strength would still be within design limits. While this all sounds good—and there hasn’t appeared to be any history of general aviation airplanes falling out of the sky because of age-related airframe failures—on April 29, 1999, a Cessna 402C with more than 20,000 hours in service did suffer a wing lower spar cap fatigue failure that resulted in a fatal crash. Because of this crash, an AD was issued (AD 99-11-13) mandating a one-time visual inspection of the area in the wing that the Cessna engineers determined may be susceptible to cracking after 10,000 hours. This AD required that the results of these inspections be submitted to the FAA for further study. This gathering-data approach to determining safe airframe life seems to be the trend that the FAA is favoring in establishing continued airworthiness guidelines as airframes age. Improved data gathering and the free exchange of information between the industry and the FAA are the main goals of the continued airworthiness summit.
Continued airworthiness programs
One general aviation manufacturer with a continued airworthiness program currently in place for its general aviation airplanes is Cessna, with its 100-, 200-, 300-, and 400-series CAP manuals. (The manuals can be bought from the publications division of Cessna.) These manuals detail inspections and, in some cases, service kits that the manufacturer has determined are necessary for continued airworthiness. It’s likely that Cessna’s continued airworthiness programs may become the templates for development of similar programs for other general aviation airplanes.
How to ensure continued airworthiness?
The answer seems to be that as long as the average general aviation airplane is maintained in accordance with the manufacturer’s service recommendations, there is no limit to the airframe time-in-service. And therein arises some big questions, especially for orphaned airplanes. More than a few manufacturers of older general aviation aircraft are defunct. In some cases, the holders of the type certificate data sheets are unknown to even the FAA. The result of this is a dearth of printed service information and guidance, zero parts availability in some cases, and no factory-supplied service or accessory kits to address design shortcomings.
Yet these orphaned airplanes are still flying, and flying safely. How can this be, you may ask? The answer is that some dedicated owners and maintenance people have learned through the exchange of information and experience how to maintain these airplanes. Often this information is not written down anywhere. Hence the need to establish a method of making this critical safety and maintenance information available for future owners before the information is lost. Orphaned airplanes are bound by the same regulations as manufacturer-supported airplanes, such as Cessnas, Beechcraft, and Pipers. Airplanes supported by an active manufacturer are a lot less likely to be rendered unairworthy by parts problems since these manufacturers—and others manufacturing parts under parts manufacturing approvals (PMA)—are still doing a pretty good job of manufacturing, certifying, and distributing airworthy parts. In addition, each of these manufacturers also has an engineering department that can approve various repairs and modifications that may be needed as the aircraft age.
How can an owner ensure airworthiness?
What about the orphans? Does it make sense to buy and fly a Funk, a Taylorcraft, or an Ercoupe? If you already own an orphaned aircraft, what can you do to make sure it’s airworthy—especially if you can’t get any support from the manufacturer? The most important thing owners can do is to find a mechanic who is extremely knowledgeable about the particular airplane. That means he has a lot of experience on your make and model of airplane. He should have all the available manuals and service information for both the engine and the airframe.
What if there is no one near you who has the requisite experience, manuals, and tooling? You can help to educate a local mechanic by taking an active part in the maintenance, especially the information-gathering phase. You may not be gifted with a wrench or screwdriver, but dedicating yourself to gathering information will take the place of those skills.
Band together with other owners and share information. Whether this means joining an organized type club, such as the American Bonanza Society or the Comanche Club, for example, or monitoring or even creating a Web page or network of knowledgeable contacts will depend upon the airplane. A current list of associations and airplane type clubs is available in AOPA’s Airport Directory and in the AOPA Online version of the directory on the AOPA Web site ( www.aopa.org/members/clubs/).
There are chat rooms on many of the aviation Web sites that are devoted to different makes and models of aircraft. Many type clubs have maintenance forums, fly-ins, and technical advisors who are able to assist owners in learning about their airplanes.
Hopefully, the general aviation community and the FAA will be able to form an ongoing partnership to establish some real workable solutions for future airworthiness—solutions that create regulations and ADs based upon the combined experience of the community to enable today’s airplanes to safely fly far into the twenty-first century.
E-mail the author at [email protected].
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