nally approved for Grade A cotton fabric. Again, there are many more to list. But, some major alterations can be approved by an A&P-IA. Other major alterations can not be approved by the A&P-IA. A few of these alterations are engine and/or prop changes, changes in wheels and brakes, changes in tail wheel installations, changes in fuel system (addition or sub traction of fuel tanks), installa tion of an entire electrical system including battery and charging system, and alteration of wing and/or control surface shape. So what happens (with the FAA) when a person buys an air plane that had been converted to a crop duster/sprayer and wants to return it to "stock" configuration? That's always a good one to analyze. The A&P-IA can remove the modi fications to the structure and replace components originally used in the airplane-and can re turn it to service. However, when all work has been completed, the FAA must do a conformity inspection to deter mine if the airplane conforms to its original type certificate, and issue a new standard airworthiness certifi cate. The old airworthiness certifi cate was in the restricted category, and it is no longer valid. The point here is that the mechanic is modi fying an existing structure back to standard, not the opposite. Thus far, in my career as an air craft mechanic, I've been through six different FAA conformity in spections, the most difficult being on my 1929 Command-Aire be cause there were no drawings or other type design data. You may be fortunate if there is a type club for your aircraft that may have a large collection of draWings for the pur pose of keeping an aircraft airwor thy. And that is a most important factor for future dealings with the FAA. We'll have more on that later. Factory drawings continue to be a most important item for aging aircraft but may be the most diffi-
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ther hard copy or microfiche, while some are still in storage. AERONAUl"ICS BRANCH And many drawings were de AERONAuncs BUI..lEnN No. 7-A stroyed. Such was the case for the Command-Aire. Where were (are) the draw AIRWORTHINESS REQUIREMENTS ings stored? Originally they OF were stored in Washington, AIR COMMERCE REGULATIONS I D.C., in the department's files. As the drawing files grew and more aircraft received the cov eted approved type certificate, the drawing files were relocated to the old torpedo factory build ing at Alexandria, Virginia. As the files continued to grow, the newly formed FAA relocated the drawings to the district office (DO) nearest to where the airplane was manufactured. Some draw ings were lost during transfer, and some were destroyed at the DO. But many drawings are still stored , at the Federal Records Storage Cen ter in Suitland, Maryland. I have -
perused boxes and boxes of original Figure 1 blueprint drawings stored there for years! It's absolutely amazing what cult to obtain. Drawings are needed is there. But no one knows exactly when the owner finds it necessary what is in each of the boxes. I have a brief transcript of what I saw in to replace a primary structural com ponent, such as wings, control sur 1982, but it's a drop in the bucket faces, fuselage, landing gear, etc. of what is actually there. Perhaps How were drawings originally this could be another column in submitted to the Aeronautics Branch the future. So drawings are a most impor of the u.S . Department of Com merce, or later the Civil Aeronautics tant item when it comes to repair Administration (CAA)? The answer ing a structure or fabricating new. lies in Aeronautics Bulletin No. 7-A What if you want to make a new dated July 1929. (See figure 1.) wing structure and there are no Within the CANs bulletin, Para draWings available? Aha! The wall graph 4-PROCEDURE reads: "The has been set and it is almost impos drawings, which the manufacturer is sible to obtain drawings from the required to furnish in duplicate, are FAA, although it is the "caretaker" of all ATC drawings. checked for conformity." After the air I will say that wood structures are plane is approved for manufacture, "One set of drawings is impressed with probably the easiest to reproduce the seal of the Department of Com from original parts, because aircraft merce and returned to the manufac quality wood is still aircraft qual turer to be used in the construction of ity wood and the component can his airplanes. The other set is placed be reverse-engineered. A major de in the department's files." It is the viation will be the type of adhesive location and access to the second used to manufacture the part. The manufacture of metallic parts pro set of drawings that is always con vides yet other challenges. What troversial (these drawings are com monly called "first copy"). Some type of aluminum is it? Was it heat treated or not heat-treated, and drawings have been released, ei DEPARTMENT OF COMMERCE
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