AOPA's Catch-A-Cardinal Sweepstakes

Airframe refurbishment 101

So you've bought an airplane. The first thing you want to do is take it apart, right?

Well, maybe you have other ideas, like flying it.

But even if you have never purchased an airplane with the word "project" in mind, you may wonder (as the hours build in your respective logbooks) what's really lurking inside your airplane's skin, beyond the inspection plates and above the headliner, underneath the carpet and behind the panel.

When we began the refurbishment process on AOPA's 2007 Catch-A-Cardinal Sweepstakes airplane, a 1977 Cessna Cardinal 177B, we already knew that a limited deconstruction of the airplane came first on the agenda. This thinking was born from the experiences of projects past, when gremlins (from poor repairs to funky wiring) surfaced once we were well into a given sweepstakes refurbishment — problems that might have been more readily addressed early on. Part of our purpose in assembling the diverse pool of talent within the sweepstakes airplane's refurbishment team at Griffin, Georgia, was to facilitate this process.

And recently you may have heard grumblings around the aviation community regarding aging aircraft. With a large portion of the general aviation fleet approaching 30 or 40 years in service, we have some valid questions to ask about the state of our airplanes (see " Waypoints: GA's Next Challenge," February Pilot). The only way to really find out what's inside is, well, to look inside. Although we can't possibly give direction for every airframe project out there, we hope to help you determine if it's worth it for you to take a similar look inside your airplane, and give you initial ideas on how to find the right people to do this job.

Because you don't want just anyone taking your airplane apart.

That said, the basics of what we did are fairly straightforward, and well within the capabilities of a good shop or a couple of decent airframe and powerplant technicians. At least one should have inspection authority (we'll refer to this as an IA technician), and at least one should be comfortable enough with either sheet-metal or composite repair to clean up any problems encountered, or repair or replace any unserviceable parts that come off the airplane.

You should take a look at past projects that your mechanics have performed (focus on those airplanes that are up and flying again — though a look at projects in process can be illuminating as well). To put it in perspective, most A&Ps would find it far more challenging to build an airplane on their own than to take a production airplane down to its framework and put it back together again. But there are certain similarities. Most of all, you need to have a plan.

How far do we go?

A cadre of sheet-metal and rivet-gun artists stood waiting to get their hands on this delicious disassembly. But before we started, our on-site project manager Dan Gryder fashioned a corner of his hangar facility to accommodate the airplane and the process with dedicated shelving and workspace. At the same time, our chief inspector and parts manager Danny Rexroad, owner of Classic Aircraft Maintenance, developed a meticulous and low-cost cataloging system to keep track of parts as they came off the airplane and to determine which ones would need repair, replacement, or just a good cleanup before going back onto the airplane.

Our process used a unique numbering system cross-referenced to the Cessna parts catalog for the Cardinal. About 100 labor hours were spent on this task, but we now have a giant binder in which we account for every part, down to the last screw removed from the airplane.

The team removed the cowling first, followed by the control surfaces (including the Cardinal's beefy stabilator), which went onto a special rack. Larger racks had been built for the wings, and they departed the airplane after a quartet of massive bolts was encouraged out from their fittings. The wide Cardinal doors (two of the airplane's most convenient features, yet requiring a certain amount of fuss and finesse because of their size) came off their hinges and were set aside for future attention. Next, Anja Cook, Brian Hubbard, Larry Gobble, Steve Dodnoruk, and Earl Clements from Air Wrench deconstructed the tail further, removing the vertical stabilizer and tail cone.

The interior came out readily — seats, carpet, and plastic moldings, and then the headliner above. With this move, the main wing carry-through spar saw daylight after three decades under cover. This impressive metal structure glowed with a golden color, protected all these years with an anodized process at the factory. That sight alone was worth the price of admission.

Don and Jeff Swords, from Don's Dream Machines, disengaged the engine from its mounts, and carefully laid out all the accessories. Then the mount itself came off the stainless-steel firewall (soon to be buffed out to a mirror shine compliments of our friends at Nuvite, which creates an entire line of aircraft care products). The airplane's landing gear was removed and the airframe placed on a rolling, purpose-built cradle for ease of access.

Last, further interior deconstruction included removing the rudder pedals and other elements near the instrument panel for inspection, and then removing the seat tracks and floorboards.

This final step (removing the floorboards) required the drilling out of 185 rivets to accomplish, but the results surpassed our expectations. We sought to assess any corrosion in this area (we found only minor, limited areas of it), and we knew we would replace the seat tracks, which were still well serviceable but worn from 4,000-plus hours of adjusting to pilot posture demands.

What we didn't anticipate was the incredible insight into the airframe structure that this step allowed. The Cardinal fuselage is actually in three parts — the forward cockpit area, the rear empennage area, and a central band, which connects the two. This central band incorporates the spar and the main landing-gear attach points, creating a centerpiece to which essentially the entire front and back of the airplane bolt on. What a lesson in engineering! And what even greater respect I have for the Cessna product as a result.

Other things we found inside: scat tubing that should be replaced for better wear; the powder of easily cleaned-up, superficial corrosion in the wings; a long list of hardware to be replaced because of stripped threads, rust, fatigue, or simply cosmetic appeal; and a lot of tired wiring.

Total time spent on airframe disassembly? About 70 labor hours. A portion of this work would be possible for an aircraft owner to complete under supervision, reducing the cost and increasing the learning potential exponentially.

Before starting your own project, you should prioritize what you will disassemble based on your goals for doing so. At one end of the spectrum, you may be looking only for major problems to address, such as corrosion, fatigue in the structure, or worn control cables. At the other end, you may be launching a full-blown restoration, in which you'll attend to safety of flight items, but also home in on aesthetic details, such as specialty hardware and fairings replacement, and minor dent repair.

Fall to pieces

I'll be honest here. As an aircraft owner commanding your own airplane's disassembly, you may need to brace yourself for the sight of your once-flying airplane in pieces. The first time I saw the disassembly, I caught my breath. But I kept in mind several key concepts throughout this initial, critical part of our refurbishment, the most important of which was the level of detail that such a disassembly would allow us to achieve in making the 2007 sweepstakes airplane a thing of beauty, inside and out. And not just from a physical perspective — no, I truly relished our ability to replace old wiring, cables, and hardware, and to inspect critical elements such as fuel lines, control cables, and primary structures within the airframe.

At times I had to call upon my memories of flying the airplane into Griffin last November to remember the fine flying machine that N18729 was — but the care we're giving it now will take this airplane to a higher level altogether. When I fly your Cardinal again, I'll fly it with confidence, knowing every piece is clean and conforming, and every part is in its place.

E-mail the author at [email protected].

Who's behind us?

The AvNet's Dan Gryder

The AvNet owner Dan Gryder has been an active flight instructor since 1982, specializing in tailwheel training and rating completions. Flight training may be the cornerstone of Gryder's résumé, but he developed The AvNet to address a diverse range of "aviation situations" for which he can figure out an "aviation solution."

Since 2001, Gryder has operated out of his large commercial hangar at the Griffin-Spalding County Airport, offering convenience for pilots who fly in to engage in virtually every kind of flight training. His company owns numerous aircraft including a Douglas DC-3. The AvNet also performs general aviation consulting such as assessing and advising corporate flight departments regarding best practices for safe, clean operations; developing marketing promotions with companies; and advocating for an aircraft owner during an airplane purchase or restoration. But he's open to suggestion: "I like to cherry-pick the neatest projects," says Gryder. Helping AOPA manage this year's sweepstakes project is a great example. Visit the Web site or call 678/688-7069. — JKB