Originally Posted by
Hughes500
Cylic hotline, shows what you dont know. One of my closest friends and neighbour MADE ( he owned the company , his father set it up, having been one of Frank Whittle's engineers making the first jet engine )them for RR so he should know. So you may eat humble pie when ever you feel like it.
I don't think I'll be eating humble pie anytime soon. I really don't care what someone else (not you, incidentally) claims to know. I'm just stating facts, and you cannot manufacture certified, rotating, hot-section parts for the price you quote, it cannot be done. Maybe your friend was a vendor for RR (who incidentally purchased the Allison Engine Company and didn't design the M250), and manufactured something for them for that price in the late 1950's or early 1960's, maybe even the 70's, but he also had no design, engineering, certification or other expenses to bear. My experience and what I'm relating to you is contemporary, goes back a long time, and is real-world knowledge.
FAA summary of PMA parts.
"The design approval phase of PMA certifies that a replacement or modification article complies with the airworthiness standards of eligible products (aircraft, engine, or propeller). The applicant shows this compliance through tests and computations unless the article is identical to the article design on a type-certificated product. Identicality means that an article is the same in all respects to an article design in a type-certificated product. Evidence of license agreement shows this identicality."
206 jock, the development of PMA parts originated for many reasons, but not least to ensure that obsolescent, or expensive, parts could be replicated under a certified design, engineering, production and quality program. The debates and fights over PMA manufacture have bruised many OEM's when the PMA manufacturers demonstrated that they maintained a production process that met all the requirements for certification. The process allowed for continued production of parts when the manufacturer had disappeared, or didn't have an interest in manufacturing, or licensing someone else, to manufacture it. Of course, the real big attraction was the high dollar, high consumption parts, that would have a ready market. These high-dollar parts could be manufactured for significantly reduced costs relative to OEM pricing (which included design, test, certification, etc), and the growth of this business was driven by the high margins that a PMA manufacturer could still generate, even pricing at 50% of the OEM's price. After exploring all the legal means, the OEM's realised that THEY couldn't control this market, and in many cases matched or bettered the deals from the PMA suppliers. There
are huge margins in these parts, but the OEM utilizes these parts to fund all the other parts of the program, a burden that is not borne by the PMA manufacturer, and is the source of all the legal language that separates the OEM's product from the parts you may legally install.
How lucrative is the PMA market? When Pratt and Whitney entered the GE/Safran CFM56 PMA market, the evolution was complete. The fighting that went on in the 1990's and 2000's was quite amazing, and spilled over into all kinds of legal and regulatory battles. Much of this defined the current PMA market, and how it functions today. There is nothing wrong with a properly designed and manufactured PMA part, but there have certainly been instances of failures caused by materials, design or manufacturing process on PMA parts - and of course, there have also been multiple instances of this with OEM parts as well. This is a good article about the approval, manufacture, use and comparison of PMA and OEM parts if you are interested.
https://extexengineered.com/marking-...cfm-agreement/