Southwest Airlines is one of  several operators using aftermarket inerting-kit components.

Airlines Gaining Inerting System Supplier Alternatives

Inerting system reliability problems open doors for suppliers

Airlines are on track to meet the FAA-mandated installation of fuel tank flammability-reduction systems by year-end, but reliability issues with the OEM-backed systems are leading an increasing number of carriers to seek alternatives to support their fleet, boosting prospects for several aftermarket suppliers.

Among those emerging from the third-party pack is Cobham. The company’s Mission Systems division—once part of Bendix—developed the first inerting application, for military helicopters, more than 30 years ago. It supplies components for the Boeing 787 and Mitsubishi MRJ systems. But its largest opportunity is evolving, thanks to missteps by competitors chosen by Airbus and Boeing to meet the FAA’s Fuel Tank Flammability Reduction mandate.

Nigel Howarth/AWST

Southwest Airlines is one of several operators using aftermarket inerting-kit components.

Southwest Airlines is one of several operators using aftermarket inerting-kit components.

The 2008 rule called for new-production versions of affected models with center-wing tanks to have systems installed starting in late December 2010. It also requires airlines to retrofit affected in-service models by Dec. 27. The rule, one of many changes triggered by probes into about 20 center fuel-tank explosions, including TWA Flight 800 in 1996, covers nine aircraft families, including the Boeing 737 and Airbus A320.

While the rule does not prescribe a fix, Airbus and Boeing opted for inerting systems, which lower the oxygen levels in tanks, removing the risk of explosion. About two years after new aircraft began rolling out with the systems installed, 737 operators began reporting reliability issues with air separation module (ASM) membranes that are key to the inerting process. Supplied by Parker Hannifin and designed to last at least 20,000 hr.—about four years—many operators were experiencing failures in half that time. 

“The system has not been as reliable as we’d like it to be,” says Kent Horton, director of aircraft engineering for Southwest Airlines. Replacement ASMs, the only way to get new membranes, are about $70,000. Enter the third-party suppliers.

Cobham in late 2015 announced its 737NG ASM offering was flying with an unnamed U.S.-based customer. It added two major North American 737 operators—and was close to signing with a third—as well as a large European carrier. It has 250 of its ASMs in service. “They are shipping pretty quickly,” says Mike Donahue, Cobham Mission Systems business development director.

In addition to Cobham, AeroParts has developed an ASM repair featuring a new membrane and fixed 100 out-of-warranty systems in the last two years. 

JetAire Group has taken a different tack, developing a system that lines tanks with a proprietary foam to suppress fuel ignition. Based on an approach used in the military for years, JetAire has kits for 737 Classics, 757s and 767s and A320s. It expects to have an approved 737NG system by mid-year.

Boeing is working on a more reliable ASM, but its time line keeps slipping. “We are working with our supplier to ensure that the improved [ASM] kits will be available in [the fourth quarter of] 2017,” Boeing says.

Meanwhile, major operators of U.S.-registered aircraft report no problems lining up kits to meet the Dec. 27 retrofit deadline. The OEM-offered kit is most popular, but carriers are using alternate suppliers to boost reliability. 

“We have worked with a third party to provide an alternate component in the system, and we’re seeing the performance on that component [is] more in line with what our expectations were originally,” Southwest’s Horton says.

The new Boeing kit’s delay plus reports of similar problems with A320-family systems suggests that the market for alternatives will be large. 

While the FAA ended up alone in mandating a retrofit (European regulators reversed course, concluding the costs were not justifiable), the forward-fit requirement was adopted globally. This means that more than 6,000 737NGs and A320s delivered since about mid-2009 have the systems.

“Many of the operators are just now coming out of warranty,” says Larry Britt, AeroParts business development manager. “There’s a huge market for us.”

This has the suppliers jockeying for position. In addition to the membrane repair, AeroParts offers a customized insulation sleeve for the 737 ASM. The part was requested by operators to ease reassembly of a repaired system, such as an ASM under warranty it sent back to Parker, Britt says.

Cobham is using input from operators to guide its product development. “We’ve flipped our focus to the end customers from the OEM,” Cobham’s Donahue explains. “We interview the customer and grade their interest [in different products]. We have a documented path of what their goal is, which helps guide our product development.”

The dialog helped Cobham develop  a seven-year warranty option for its ASMs. Now some customers are asking for a “life-of-aircraft” option, which would run about 14 years, or two average leases, Donahue notes. “It’s taking the subsystem off the radar screen for the airline,” he says, adding that customer data show inerting systems are among the three costliest subsystems on some aircraft models.

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