The Bell Helicopter 407 is one model that Donaldson Aerospace supplies with IBFs. Photo courtesy of Donaldson
The SAE S-12 Helicopter Powerplant Committee is slated to propose changes to the FAA requirements for inlet barrier filter certifications by the middle of next year, the FAA said Oct. 16.
Designed to keep dirt, dust, sand, foreign objects and other contaminants from entering a helicopter engine, IBFs can provide greater protection than traditional particle separator/inertial separator systems or foreign object debris (FOD) screens. IBFs are relied upon by operators flying from unimproved locations on firefighting, rescue and utility missions, and have been used widely by the U.S. military in operations in Iraq, Afghanistan and similar areas.
In January 2016, the FAA posted a policy on IBF installations to remedy what the agency said was a lack of guidance on the topic. The FAA also issued a policy statement in May last year that reflected many of the changes.
"Due to the level of interest and comments received on the FAA’s proposed IBF policy statement when it went out for public comments, we reached out to industry to seek their help in forming a committee to develop alternate methods for IBF installations," FAA spokesman Lynn Lunsford wrote in an email Oct. 16. "The SAE S-12 Helicopter Powerplant Committee accepted our request and initiated this effort in February 2017. Major U.S. and European rotorcraft and engine manufacturers, along with IBF modifiers, are supporting this task."
"The FAA’s Rotorcraft Standards Branch has been participating in the SAE S-12 meetings, along with the Transport Canada Civil Aviation (TCCA) and the European Aviation Safety Agency (EASA)," Lunsford wrote. "The focus of the committee is on alternate methods to evaluate engine inlet distortion and to establish power available for IBF installations. The committee is targeting to complete their task by mid-2019. Once completed, the FAA will review the committee’s recommendations and adopt into the FAA’s rotorcraft IBF policy statement, as appropriate."
Most IBFs have been installed under supplemental type certificates (STCs) issued by the FAA or foreign aviation authorities to verify the safety of the installations. To obtain certification, the FAA proposed changes for IBF-equipped helicopters to demonstrate that they are staying within limits for engine inlet distortions and that the IBFs do not compromise power available from a helicopter’s engines.
But the changes have led to complaints from companies, including Donaldson Aerospace and Aerometals, the two leading IBF manufacturers in the United States, about the compliance burden, increased time to get new IBFs on the market and falling sales.