Donaldson Brings Cost-Saving Filtration System to Helicopter Operators

By By Joseph Ambrogne | March 2, 2015
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Bob Stenberg

When money is tight—which, if we’re being honest with ourselves, is almost universally the case in this industry—aerospace buyers focus inward on cost centers rather than outward on the cutting edge. And with the latest drop in oil prices and U.S. defense spending, rotorcraft operators may forgo the next best ride and instead look for subtler ways to extend the life of their current fleets. Heli-Expo 2015 is bringing with it a slew of next generation airframes, composite materials, satellite communications systems, and state-of-the-art glass cockpits; all of which are set to revolutionize the industry. And while it may not have the flashiest technology, Donaldson Aerospace Filtration, a provider of the engine-saving inlet barrier filter (IBF), may nevertheless turn the heads of attendees who are increasingly eager to reduce costs.

Operators must adhere carefully to both FAA-prescribed inspection intervals and the manufacturer’s estimated time before overhaul (TBO) to keep their engines free of corrosion, wear-and-tear, and foreign debris. But even the TBO is an optimistic number, presenting an estimate of the engine’s lifespan in ideal conditions. In harsher environments, helicopter engines come into contact with higher amounts of foreign particles—like salt, dirt, ash and sand. Often, these engines never last to the recommended TBO, forcing operators to ground their aircraft more often and spend more money on repairs. “The compressor impeller, say, on a 250 Rolls-Royce engine, is about a $70,000 part,” says Bob Stenberg, Donaldson’s business development director. “Without a filter, you’d have to throw that part away at overhaul. And the life of the part is maybe two or three overhauls, so if you keep it on the engine longer, you’re saving that amount of money for a period of years. We hear that consistently across operators for most of our systems.”


Donaldson has been providing filtration systems for 100 years, and—with its acquisition of Aerospace Filtration Systems—aircraft engine filters since 1999. Now the company custom designs a full service of filtration systems for rotorcraft engines. The IBF is its most successful product, filtering out almost all of the particles that would otherwise damage an engine. “It’s 99 percent efficient on particles all the way down to close to three microns,” says Stenberg. “It takes all of the dirt out of the air and keeps the air going into your engine clean. So with clean air, the engine operates to its TBO; it isn’t removed early.”

For many operations, the difference is huge. This is perhaps nowhere truer than for Military helicopters flying in the desert climates of the Middle East. Stenberg explains how the company extended the life of Kiowa Warriors in Iraq: “That engine had barely reached TBO in the United States,” he says, “and when it first went over there, the engines were being replaced at about 100 hours for low performance. But after they put the barrier filter on, the engines went to TBO. I think at the time, their TBO was like 1800 hours; it might be 2000 now. Every engine in country in the desert is reaching its TBO.”

Most recently, the company received a supplemental type certificate (STC) to produce IBFs for the Airbus EC130 T2. Though he doesn’t have any specific data on EC130 engine efficiency for a given operating environment, Stenberg estimates that, “they might go close to 800 or 1000 hours, but really the TBO on the engine is 2,000 hours — they are only getting halfway there.“ Regardless of the flight time saved, the new IBFs will make scheduled maintenance easier. “The thing we hear a lot is that when I take my engine to overhaul, I have to replace a bunch of very expensive parts. But with your filter in front of the engine, you know the tear down and the engine almost looks squeaky clean,” he says.

After the EC130 T2, Donaldson has five more STCs and three major Military programs in development. Additionally, OEMs are increasingly working with Donaldson to incorporate IBFs on new airframes, rather than simply adding them to models already in service. Bell Helicopter is equipping IBFs on its Military V-22 tiltrotors, as well as its commercial 505 and 525. AgustaWestland is also is putting IBFs on one of its newest models, the AW189.

In terms of rotorcraft mission profiles, Stenberg lists police, EMS, tour and utility operators as among the customers most likely to benefit from the IBF. In particular, the company is looking to make inroads into the offshore sector, where helicopters are particularly subject to corrosion from salt water. “We’ve got test data that shows we can take approximately 90 percent of the salt out of the air and the spray that comes into the engine,” he says. “So with, that and with some of the other things that we are doing, we absolutely think that we will be pushing those products into that industry more and more.”

Other companies, such as Pall and FDC Aerofilter, make barrier filters similar to Donaldson. Stenberg doesn’t denigrate the competition, acknowledging that both companies provide solid products. But in comparison, he sees the Donaldson IBF as a higher quality system at a reasonable (if slightly higher) cost. ­

Related: Engine News

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