Aerometals has secured its long-awaited supplemental type certificate (STC) approval for its Sikorsky S-92 inlet barrier filter (IBF). The STC culminated a five-year certification process that involved some 100 hours of flight testing and a $6 million investment on the part of the El Dorado Hills, Calif.-based aerospace parts manufacturer.
The STC was Aerometals’s most extensive and costly process yet, as the manufacturer worked with the FAA to satisfy certification requirements. The process had slowed as the FAA has been ironing out its policy guidance on approvals for rotorcraft IBFs. “It really has been a huge undertaking for us,” said Aerometals executive director Lorie Symon. “We’ve learned a lot. The FAA has learned a lot. It is really going to give us a good basis going forward…on how we can streamline these processes and make them more efficient.”
The FAA Los Angeles Aircraft Certification Office worked closely with Aerometals, she said, as it tried to meet the “spirit of the regulation.” For development, Aerometals used the latest generation computational fluid dynamics modeling software to maximize the filter design efficiencies and predictability, including modeling for turbulence mitigation, shape design and optimization of the overall filter performance and protection characteristics.
The IBFs are designed to protect against ingestion of salt, sand and other potentially corrosive materials, and as a result, extend power margins between overhaul intervals, and reduce possibility of premature engine removals. This filter not only substantially reduces foreign object damage and engine compressor erosion, but significantly limits salt nuclei ingestion during offshore operations, the company said. Symon noted that during testing, the filter media was shown to limit well over 90 percent of salt nuclei ingestion.
The S-92 IBF STC results in no changes to published performance, she said. The IBF, however, is currently restricted in flight into known icing and flight in falling and blowing snow. Symon noted that a large number of S-92s operate in warmer locations, such as the Gulf of Mexico. But she added, “We will at some point do the falling and blowing snow flight testing. That unfortunately requires you to chase the weather.”
Aerometals worked to ensure there were not other substantive operational restrictions, she added. “That was one of the reasons the S-92 took us as long as it did. We were unwilling to accept unreasonable restrictions.” Limiting weight on a transport category helicopter such as the S-92 would have been a “deal killer,” she said. “If I can carry 20 people out to an oil rig but put a filter on and can only carry 18, I am losing more revenue than saving by using the filter.” That was not a choice that Aerometals wanted to present to potential customers.
Sikorsky had partnered with Aerometals and was willing to share extensive inlet distortion data required for the approval, Symon said. Noting that the data requirements are a significant obstacle in the FAA’s proposed policy guidance, she added, “identifying projects going forward, at least until new standards are finalized, that is something we are going to take into account. We must have either an airframe or engine manufacturer that is willing to share the data with us.”
While the STC was in progress, Aerometals had stopped taking letters of intent because of the uncertainty surrounding the timing. But with the approval in hand, “We are hitting the ground running, and the response has been tremendous,” she said. Operators in the Middle East, North Africa and the Gulf of Mexico have especially shown interest.
Aerometals has begun production and was planning to ship the first several kits before Heli-Expo. At the same time, the company is eyeing an expansion that will double its footprint. The company acquired a neighboring lot and is building a second 75,000-sq-ft plant that will enable it to expand manufacturing capabilities.
As it ramps up on the S-92 filter, Aerometals already has identified future projects, including an IBF for the Airbus Helicopters H130 (formerly EC130T2). That project already has been submitted to the FAA to begin the certification process. The company has already obtained the necessary inlet distortion limit data on the project. Aerometals further is in negotiations with an engine manufacturer for another aftermarket kit.
Aerometals also offers IBF kits for various other Bell, Airbus, MD and Sikorsky models.