The aircraft maintenance professional's source for technological advancements, maintenance alerts, news, articles, events, and careers
Issue link: http://amt.epubxp.com/i/789984
AIRCRAFT MAINTENANCE COMMERCIAL MRO 16 JANUARY/FEBRUARY 2017 TECHNOLOGY the decision to use OEM or PMA parts is often driven by the customer so they offer both options. According to Grimshaw, independent MROs tend to specialize in specific components or sub- systems within the aircraft. For Triumph Accessory Services that means electrical generators, hydraulic pumps, pneumatic valves, air cycle machines, vari- ous types of actuators, and power generation and transmission equipment. The bulk of the work comes from air carriers that no longer perform in-house repairs, from parts brokers and distributors that need components tested, repaired and overhauled to resell, and from freight carriers converting passenger aircraft. OEM repair shops, on the other hand, can offer a broader portfolio of parts. In addition, they can offer air carriers parts at below-catalog rates, while the MRO often must pay full price. Therefore, to compete effectively, third-party repair shops often promote the use of PMA parts. Rich Simmons, operations manager at Texas Pneumatic Systems (TPS), a third-party MRO that specializes in pneumatic, fuel, and hydraulic com- ponents, concurs. "If a customer is looking for a cost-effective solution, we want to be able to offer them the PMA parts because they are less expensive than the OEM," says Simmons. "For our service, we would be remiss if we didn't offer that." TECHNOLOGY, QUALITY, AND PRICE A prime example of the push-pull between OEM and PMA provider can be found in the main- tenance and repair of environmental control systems used in most military and commercial aircraft. Environmental control systems (ECS) provide air supply, cooling and heating, and cabin pres- surization for the crew and passengers. Major OEMs such as Honeywell, United Technologies Corporation Aerospace Systems (UTAS), and Liebherr dominate the market. A key component in these systems is the air cycle machine (ACM). To produce cool air without the uses of a refrigerant, such as Freon, this high- speed rotating machine utilizes sophisticated foil air bearings that conform to the shape of a mating rotating shaft. Most commercial and military air- craft today utilize ACMs with this type of bearing. However, at 30,000 to 45,000 rpms even well- manufactured foil bearings can fail or wear out from constant use over time. When this occurs, the ACM may fail to operate in-flight. More serious failures or imbalances of the rotating elements can also cause ancillary damage to other components in the air conditioning pack. INDEPENDENT MROS recommend PMA parts, like the air cycle machine (ACM), because these parts offer the same quality but are less expensive. Come see us at Heli-Expo 2017 March 7th - 9th 2017 Kay Bailey Hutchison Convention Center Dallas, TX Booth #: 8109