SAE To Tackle Helicopter IBF Standards

The FAA has tasked SAE with developing a recommended practice standard on an alternative means to substantiate that an inlet barrier filter modification on a helicopter does not exceed engine inlet distortion limits. Even though it has been trying to draft a policy statement on IBFs for some time, Donaldson Aerospace & Defense still received U.S. approval for its dry media IBF for the Bell 407 in July.

(Photo: Donaldson Aerospace & Defense)

The U.S. FAA, which has long been working on a policy statement for rotorcraft inlet barrier filter (IBF) installation, has turned to SAE International for help on two technical aspects. SAE was tasked with developing a recommended practice standard on an alternative means to substantiate that the IBF modification does not exceed engine inlet distortion limits. The FAA also asked SAE to define a means to determine and verify power availability for IBF-equipped rotorcraft.

SAE’s S-12 Helicopter Powerplant Committee is taking the lead on the standards with help from the S-16 Turbine Engine Inlet Flow Distortion Committee. A virtual committee meeting is scheduled for February 15 to begin work on the standard, with a face-to-face meeting on March 9 during Heli-Expo.

“We are pleased to be working with the FAA on the development of these important rotorcraft standards and appreciate the trust that the FAA has placed in SAE International to use industry standards as guidance material,” said David Alexander, director of aerospace standards for SAE International. Power availability and engine distortion limits have been two of the more difficult issues that the FAA has faced as it has attempted to put together a policy on IBF installations.

The FAA has been sorting through public comments it received on a draft policy statement released a little more than a year ago, an agency spokeswoman said. Noting the SAE activities, the spokeswoman added, “Our hope is these tasks will result in Aerospace Recommended Practices that can then be referenced in our helicopter advisory material.”

The draft policy had generated substantial opposition because it called for detailed proprietary engine data that manufacturers tend to be reluctant to share publicly. In addition, industry executives expressed concern that the original policy had included the potential for performance penalties that would render IBFs impractical and would drive up certification costs considerably. The primary aftermarket providers, Aerometals and Donaldson, questioned whether they would be able to remain in the market should the draft policy become final as originally written.

FAA officials have said they would carefully consider the comments, but the agency has maintained, “The increased usage of…IBF installations on rotorcraft requires guidance to ensure safe and standardized installations.”

The FAA has not released a timeline when a final statement might be released. Timing of the SAE standards also was unclear, but an SAE spokeswoman said that on average, the development of standards and recommended practices could take between 18 and 24 months.

(Kerry Lynch - AINOnline News)