337's are not normally used or necessary to "fix" things, using PMA'd parts. There are some exceptions however. Changing something that isn't original, is considered a Modification, and needs STC approval, even if the part is PMA'd. But replacing original parts that are considered "airworthiness " items, needs to be done by your Ap/IA, or under his direct supervision.I could get into " as good as or better than", but that too requires field approval, and an STC, and I don't think that was part of your question anyway. A good example came up just today. Someone wants to change the carpet in a certified aircraft, and thought going to the carpet store was ok. It isn't. All materials used in a certified aircraft have to be FAA Approved for that use. A freshly painted and renovated aircraft is a red flag to the FAA. If they see new carpet, they can require that you furnish the receipt, if the material isn't tagged, to prove it's source. They can ground the plane, or furnish you a permit to return to base, then ground the plane till you either furnish a receipt, or remove the item. My advice to the person in question was to by legitimate materials, and if not tagged, carry the receipt in the certificate holder, just in case. The guy didn't like my advice, But these FAA ramp guys know what there doing, and are pretty sneaky in the process. Just remember, the stranger in the coffee shop or on the ramp or in the ready room is not your friend unless proven so. Doug
<<attachment: winmail.dat>>
