Story ID: 135March17
SAE To Tackle Helicopter IBF Standards
By: Kerry Lynch
Caption: The FAA has asked SAE to work through two of the more difficult issues as it attempts to complete a policy statement on IBF installation.
Word Count: 791
The FAA, which has long been working on a policy statement for rotorcraft inlet barrier filter (IBF) installations, has turned to the standards-setting organization SAE International for help on two of the most difficult technical aspects surrounding that policy.

The 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 the organization to define a means to determine and verify power availability for IBF-equipped rotorcraft.

The FAA made the request as it has been hashing out concerns expressed in response to a proposed IBF policy it released a year ago. That draft policy generated so much opposition that the agency extended the comment period and then held a public meeting to receive industry input.

Operators, aftermarket providers and other industry groups have expressed concern that the policy would require detailed proprietary engine data that manufacturers tend to be reluctant to share publicly. In addition, industry executives expressed concern that the original policy 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 IBF market should the draft policy become final as originally written.

FAA officials have said they will carefully consider the comments, and Lorie Symon, executive director for Aerometals, noted that the “huge industry response during the public comment period really got the FAA to see how important an issue this is to operators and to the helicopter industry.”

Symon said that outdated regulations created some of the obstacles to satisfying the FAA’s requirements in the draft policy. “The FAA agreed that this is a safe technology. We were just running up against regulations that are decades old and written in such a way that it was hard to figure out alternative methods of compliance.”
Significant Hurdles
Many of the issues of the original draft policy statement have been worked out, but the two remaining issues—inlet distortion limits and power assurance checks—remain unresolved. The issue of inlet distortion limits “comes right down to whether or not we can get the information we need from the manufacturers. We’ve got to solve that dilemma before we can discuss all the different means of compliance,” Symon said.

Obtaining proprietary data “is probably one of the biggest issues that the SAE committee is going to struggle with,” she said. But she noted that manufacturers are required to release certain data through their type certificate data sheets. “One of the things I would like the SAE committee to explore is whether it is possible to make the inlet distortion limits a part of that information.”

Power assurance checks are a technology issue, Symon said, noting that existing power check data already takes into account effects of potential losses of power from IBF installations.

“We have to resolve these two issues because they are major,” Symon said. “If we cannot come up with an alternative means for us to be able to prove that we are not affecting inlet distortion, we are done. If the engine and airframe manufacturers say, ‘No you can’t have that data,’ then we are done. There is no way around it.”

But Symon expressed hope that the SAE committee will be able to work through these issues. “Unfortunately it is not a short process, but it is a good first step.”

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

The 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. Aftermarket providers, manufacturers, operators and other interested parties will participate. A virtual committee meeting was scheduled for February 15 to begin work on the standard, with a face-to-face meeting to be held on March 9 during Heli-Expo.

 “Our hope is that these tasks will result in Aerospace Recommended Practices that can then be referenced in our helicopter advisory material,” an FAA spokeswoman said.

 “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.

 
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