PMA Parts: Baseless controversy or industry problem?

Aviation International News » June 2004
October 8, 2007, 10:10 AM

“As an OEM we look at the product as a whole and not just as a collection of individual parts. We design our engines as an entire system,” Wayne Russell, manager of parts support for Pratt & Whitney Canada, told AIN. Russell said some engine parts have a high enough turnover rate that it becomes economically attractive for some companies to produce them for aftermarket installation.

According to FAR 21.305, parts approved for use on aircraft must conform to FAA-approved production standards. Two of the most common methods are in conjunction with the equipment manufacturers’ type-certification procedures (often referred to as OEM parts) and FAA approval under a Parts Manufacturing Approval (PMA). Many, if not all, OEMs take issue with PMA parts for various reasons.

OEM management rightfully views most PMA parts as competition, but occasionally the feelings run much deeper than mere competitiveness. Some OEMs resent PMA manufacturers as “poachers,” stressing that the OEM does all the engineering and testing for the part and then a PMA manufacturer reverse engineers it and applies for PMA approval. “We pay the freight for the research and development, and then along comes some outfit that takes our part, looks it over, makes a blueprint and gets a PMA authorization from the FAA,” one airframe manufacturer’s engineering department chief said.

Russell said there is more to parts than simply manufacturing and providing them to the customer. Acknowledging a PMA part might cost less than the OEM version, Russell explained, “We give you more than the part itself; you get extensive support. We have technical publications, documentation, field support, training, service centers and a 24-hour help desk. And we keep all the replacement parts in inventory, even those that rarely turn over, so it really is one-stop shopping.” Russell said the company continues to support all of its engines, including the original PT6A-6. “It first went into production in 1963 and we stopped making it in the early 1970s but we support it fully to this day.”

Peter Boyd, chief engineer of customer support for Pratt & Whitney Canada, added, “We work hard to get AOG parts to the operator as fast as possible. We’re a 24/7 operation and have a mobile repair team we can dispatch anywhere in the world to work on an aircraft that’s grounded. Of the 56,000 engines we’ve built since we started business in 1963, 40,000 are still in service and we still support them. If one can’t be repaired on wing, we maintain a fleet of rental engines for our customers.”

Despite the benefits associated with most OEM parts there is another side of the story.

Larry Shiembob, president and CEO of Mesa, Ariz.-based Extex, manufactures and sells PMA Rolls-Royce 250 engine parts. “Any marketplace works better when there’s competition, and PMA manufacturers are competition. Competition brings technical innovation. The notion that companies that offer PMA parts don’t provide support is simply wrong.” Shiembob stressed the technical benefit.

 “What we do as a PMA designer is address the service difficulties associated with an OEM’s original type-certified (TC) part,” Shiembob explained. “Under the best of circumstances, a given OEM is going to discover some unpredictable problem with some part. Or perhaps technology will advance after the original design, making it possible to produce a better part. There’s little incentive for an OEM to revamp its process and have the new version of a part approved by the FAA when it is already selling the part as is. A PMA manufacturer doesn’t have an inventory of original parts to sell, so it can design a replacement part using state-of-the-art technology. In the end the customer gets a much better part.”

Shiembob offered as an example the Rolls-Royce 250 nozzles his company makes for the aftermarket. “Our process increases nozzle life from the OEM’s 700 hours to more than 3,000 hours,” he said. “We can look at what exists, look at the issues, engineer it better and produce it.”

Shiembob agreed that some OEMs maintain their products for many years, but he said some don’t. “Some OEMs are too busy to support older product lines, so a PMA manufacturer will come along and fill that niche.” He also noted that some OEMs will have informal, and in some cases even formal, arrangements with PMA providers to support product lines the OEM no longer does. He added. “Everyone knows what happens when there’s no competition in a given marketplace. The only provider then makes the rules and it can do whatever it wants.”

Shiembob also pointed out the initial cost of a PMA part is frequently less than the original, but equally important the real saving is often in the improved durability as a result of better materials, tighter tolerances and reduced life-cycle costs.

From the FAA’s perspective, there is no legal difference between OEM and PMA parts. Most FAA personnel are no longer allowed to talk directly to media, but someone very familiar with the PMA and OEM approval processes said, on condition of anonymity, that PMA applications must show how the new part meets or exceeds the requirements set forth by the original TC holder.

Mike King, v-p and general manager of distribution for Wood Dale, Ill.-based AAR, said, “We represent about 350 OEMs that may not have the infrastructure to market themselves effectively, but we don’t just sell parts; we also sell service.” According to King, AAR is a supply-chain management and inventory-logistics service. “We contract with the end user to supply and repair their parts,” he said. “We provide a just-in-time inventory and track their parts in the repair process.” Despite doing an extensive OEM parts business, the company also sees the value of PMA parts.
“We have our own PMA group,” King said. “We design, manufacture and sell PMA parts specializing in Pratt & Whitney and GE engine parts and Honeywell APU parts. Beginning this month, we are embarking on a project to move into PMA parts for airframe, accessories, landing gear and structures.”

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