I flew down to Battle Creek to pick up my friend Randy Greene, who had flown his Waco Classic in from New York. Randy heads up Safe Flight, a family-owned company that is the leader in developing and producing flight safety technologies. Randy’s dad, Leonard, holds the fundamental patents on stall warning and measuring angle of attack and those became the foundation of the company more than 60 years ago.
Randy was returning his airplane to the Waco factory to have the 275-hp Jacobs radial replaced by the relatively new 300-hp version. The extra horsepower, and a new MT propeller that the bigger engine spins, adds 30 percent to takeoff and climb performance, and several knots more cruise speed for the classic biplane.
I have been to Waco’s factory before, but the place continues to amaze me. The whole operation is really quite small. Waco president Peter Bowers points out that they build more airplanes per square foot of factory than any other company.
Waco’s factory looks more like a homebuilder’s hangar than any other airplane factory I have ever been in. The woodworking shop is on a platform that is built above the main hangar floor. There are jigs to hold the tubing in place to weld up the fuselage frame, and over in one corner the finished fuselage and wing frames are covered in fabric. A skilled homebuilder would use essentially the same techniques.
But as usual, appearances can be deceiving. The Waco factory is very different from a homebuilder’s shop because the Waco Classic YMF-5 is an FAA-certified airplane. What that means is that every beautiful classic biplane that rolls out of the factory must conform exactly to the type certificate so that the FAA, and more importantly the new airplane owner, knows exactly what he is buying.
When we think of certifying an airplane what usually comes to mind are flight tests to demonstrate controllability and performance, and load testing to confirm that the airframe is strong enough to meet all of the requirements. Flight and load testing certainly are crucial aspects of certification, but the fundamental aspect of certification is the documentation and process control that confirms that a finished airplane conforms to what was tested.
Peter’s favorite example of how the certification process works is a Waco wing rib. The rib is the typical wood bow and truss design that looks like the ribs that youngsters build on their first try at Oshkosh. But at Waco, every wing rib has dozens of part numbers, each with an FAA-approved specification.
Each gusset on the rib has a part number that defines every detail of its size, shape, and material – in this case, which kind of wood. The stainless steel staples that fasten the gusset have a part number and approved description. Even the glue has a unique part number and approved specification.
Does all of this documentation and material tracking make the Waco wing rib better and stronger than one a skilled homebuilder would fabricate? I doubt it. But that’s not the point of certification. What certification does is make certain to the greatest extent possible that every wing rib produced at Waco is the same as the others.
This conformity to a detailed specification does two things: First, it ensures the airplane and its structure will perform the same as the airplane that was tested and approved. Second, conformity provides a method to correct problems that occur during an airplane’s life. When all components and construction methods are consistent and documented a problem in one airplane is likely to appear in others, so an airworthiness directive can be developed to solve the problem in all like airplanes.
Waco Classic has made hundreds of improvements to the original 1930s design and each change has been approved and documented under normal certification rules. Most of the changes are to improve pilot convenience and the overall durability and serviceability of the airplane, but some changes improve the basic structure such as changing to a stronger steel for the fuselage frame tubes. Even when a change is a clear improvement – such as using stronger steel alloys – the change must be tested, approved, and fully documented.
The Waco Classic factory is a great lesson in why we need both homebuilts and certified airplanes, and how different the two airplane building methods are even when they appear to be very similar on the surface.
The homebuilt rules allow a builder to experiment, to try new methods and materials while still remaining within the bounds of accepted aircraft construction techniques. A homebuilder is creating an airplane for himself and has a great deal of freedom to change a design that may not originally be his own to make it better, or at least to make it unique.
On the other hand, a certified airplane is built for any pilot. Certification does not make an airplane perfect, or even desirable. But the entire process of establishing a standard and then sticking to it in excruciating detail gives the airplane buyer what he is expecting. I think it is impressive – even amazing – that the FAA’s certification process is able to accommodate an airplane like the Waco Classic.
The Waco was a good design nearly 80 years ago; it’s better now, and the certification system makes certain each individual airplane conforms to that design. When I get frustrated with the FAA I try to remember Waco and that if an airplane has a sound design and the factory is willing to document its procedures, the certification system works.