From the professional to the owner/maintainer, it all starts with the right stuff. The wrong stuff can kill.
The right I am referring to in this case is more down to Earth than moon walking, its the right hardware for aircraft maintenance and repair. My personal odyssey for the right hardware begins with the purchase of an airplane in 1985, when I figured we could only afford to own an airplane if we took care of it ourselves under the supervision of an A&P Airframe and Power Plant. That is when our annual pilgrimages to Oshkosh began. We enjoyed the shows and demonstrations but the seemingly endless supply of hardware and tool vendors was just as fun. For a flea market shopper, those bins of parts are close to heaven on Earth...or are they? All those bits and pieces are useful only if you know your way around the aircraft hardware lot. Bluntly, using the wrong fastener or fitting in the wrong application can be a fatal mistake. And trust me, some of the guys selling this stuff at flea markets my know less about it than the buyers, or worse yet, be willing to tell you anything they think you want to here irrespective of reality. That said, there are also well known vendors of know quality hardware to be found here as well as such as Aircraft Spruce or dedicated small operations that have been in business for years and have a permanent place of business other than a vendor's booth at various flea markets. I just think buying hardware by the handful with no paper trail for anything structural is risky business, homebuilder or not.
STANDARDS EXPLAINED
This should go without saying, but I will say it anyway: The hardware you should be using on your airplane ✈is NOT the same thing you find in a typical local hardware store. And don't be misled to thinking that the stainless steel bolt that you buy at Ace is the best stuff. It is not and in fact, stainless is generally a lousy choice for any strength application. Hardware store grade 5 and grade 8 bolts may meet strength requirements. AN (the acronym for Army/Navy), NAS (National Aircraft Standard) and MS (Military Specification) hardware is specialized material and often quite expensive compared to even the premium stuff sold in the local hardware store. Expensive is relative 15 cents rather than 5 cents. AN hardware is by far the most common of the three standards, but finding it in low cost abundance is akin to the search for the Grail. And yet buying hardware from the dealer or the aircraft manufacturer is a bit like the quest for gold artifacts at times. That said , in some instances, we would use no other source, such as for wing bolts. That may be the only way to tell it you are getting the genuine article. FBO's Fix Base Operators sometime have hardware stocks and if you find a good supply locally that can be bought on an as-you-need-it-basis, consider yourself lucky.
SURPLUS SOURCES
I wouldn't use an airshow fly market, or any other surplus source for critical or safety-of-flight applications or where high strength bolts are required. Counterfeit parts are an unfortunate fact of life and they could just as easily show up in the bins at Oshkosh as anywhere else. That is were the dealer and manufacturer becomes the source of choice. Wing bolts for a Bonanza, for example, are extremely precise and cost hundreds of dollars if bought from Raytheon OEM. But it's the only choice we will make in such a critical application. Any replacement bolts should be new and have some measure of tractability and quality control. Keep in mind that some bolts MUST be new for each use, as they stretch in a way calibrated into the torque value prescribed for the installation. This true for things like rod bolts but also in other applications. Refer to the aircraft service manual for detailed specs.
PARTS IS PARTS
Using the right stuff is NOT an option, it's required by the FAR 43.13 (b) for production aircraft. I don't want to sound to morbid here, but if evidence of unapproved hardware was found on your airplane after a reportable accident you and or your mechanic could find yourself in an enforcement tussle with the FAA Federal Aviation Administration. The insurance company might make noise about it, too, although case history suggests they eventually pay up anyway. In my view, it's not worth testing the issue. FAR 91.7(b) places the requirement for assuring the aircraft is in airworthy condition prior to flight on the owner/operator. So the bucks stops in the left seat, sooner or later. Other than small hardware items such as nuts and bolts, all aircraft parts are manufactured under an approved production inspection system, a production certificate, a (TSO) Technical Service Order, or (PMA) Parts Manufacturing Authorization and should have the appropriate (ID) Identification mark or tag. AN bolts can commonly be identified by head markings, which can identify the manufacture, material, strength, purpose, corrosion resistance, etc. They also come in clevis and eyebolt configuration.
CONCLUSIONS
I have only touched on the subject of hardware to raise your awareness of an under-appreciated Safety-of-flight item. It using the right hardware unfortunate that this is often overlooked because it's seemingly so simple. Also, using the right hardware can be a huge time sink in chasing down the right items for the job and it's tempting to just skip it. But you can NOT just do that. That is why having a good AN hardware supply on hand is a worthwhile project for any owner like myself doing his own maintenance . AC43.13-1B covers this in much greater detail and I think is a must-read {dry as it is} for anyone interested in doing aircraft maintenance at any level. Now, and particularly in the future, the Internet will play an increasingly important role, as trustworthy sites for equipment, hardware and information become available and better known. An excellent point to begin an Internet search is www.avweb.com. You can find an entire cross-section of aviation related topics and breaking news. (-:
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