Egads! How do I know if my homebuilt is airworthy?

Robert Daniel

Originally published August 1994

As with any aircraft, it is the pilot's responsibility to know if the aircraft he is about to fly is airworthy. For most pilots, a good preflight will reveal most major defects but he still places a great deal of trust in the designer, manufacturer, and the last mechanic who laid hands on it. Since in the homebuilt arena, the manufacturer, mechanic, and the pilot are often the same person, a lot of responsibility falls on his shoulders. During the construction and early flight test stage, most builders are careful and conscientious enough to do a good job and you're probably no exception. But what happens when you have to do the first annual on your aircraft? Will you be able to find all the defects? Will you be able to fix the ones you find?

The real scope of this article is to give you some things to think about as you build your aircraft. Thinking about them now may give you the opportunity to make your aircraft more maintainable and, in the long run, more reliable. So here goes. When you look over your project, keep in mind the following items that you'll have to inspect every year:

  1. MOVEABLE PARTS for: lubrication, servicing, security of attachment, binding, excessive wear, safetying, proper adjustment, correct travel, cracked fittings, security of hinges, defective bearings, cleanliness, corrosion, deformation, sealing, and tension.
  2. FLUID LINES AND HOSES for: leaks, cracks, dents, kinks, chafing, proper radius in bends, security, corrosion, deterioration, obstruction, and foreign materials.
  3. METAL PARTS for: security of attachment, cracks, distortion, broken welds, corrosion, condition of paint, and other apparent damage.
  4. WIRING for: security, chafing, burning, defective insulation, loose or broken terminals, heat deterioration, and corroded terminals.
  5. BOLTS IN CRITICAL AREAS for: correct grip length, torque, safetying or locking devices.
  6. WOOD STRUCTURE for: security of joints, dry rot, fungus, separation of ply on plywood panels, grain separation, contamination, cracks, dents, and metal corrosion stains.
  7. COMPOSITE STRUCTURE for: cracks, dents, exposed fiberglass cloth, delamination, discoloration, paint, and primer deterioration.
  8. FILTERS, SCREENS, AND FLUIDS for: cleanliness, contamination, and/or replacement at specific intervals.

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Contents of The Leading Edge and these web pages are the viewpoints of the authors. No claim is made and no liability is assumed, expressed or implied as to the technical accuracy or safety of the material presented. The viewpoints expressed are not necessarily those of Chapter 1000 or the Experimental Aircraft Association.
Revised -- 27 April 1997