The Bell Helicopter 407 is one model that Donaldson Aerospace supplies with IBFs. Photo courtesy of Donaldson
A new SAE effort, requested by the FAA, could help bridge the divide between that agency and equipment manufacturers (and their customers) over how to best demonstrate the safety of engine inlet barrier filters (IBFs) on helicopters.
The dispute over proposed FAA changes to certification practices for inlet barrier filters has stalled approval for most new installations of the devices for nearly a year. It has had a major impact on businesses of Aerometals and Donaldson Aerospace, two main IBF makers.
“Instead of the FAA coming up with a policy and then us having to fight against it, this is an opportunity for the FAA and industry to sit at the same table and hammer it out,” said Lorie Symon, executive director of El Dorado, California-based Aerometals. “It's no longer just the IBF manufacturers that are part of this. So it's really the rotorcraft industry coming together to figure this out.”
About two dozen individuals have answered SAE’s Jan. 9 call for subject matter experts to join two standing committees newly tasked with finding ways to verify that the installation of IBFs do not degrade the performance of helicopters or the engines for which they are installed. SAE’s liaison on the project, Aerospace Standards Engineer Laura Feix, told R&WI respondents include representatives of the major rotorcraft manufacturers and (to date) all but one helicopter engine maker, as well as the IBF companies and helicopter operators.
“We'll be meeting with people that build engines for a living, and people that actually fly the aircraft and probably have the best perspective on what's safe,” said Matt Fortuna, general manager of Global Aerospace & Defense at Donaldson. “The users, operators and equipment manufacturers will have a good perspective on what they need to be using on their aircraft.”
The international engineering standards organization plans a Feb. 15 online meeting of committee members to launch the work. A follow-up, face-to-face meeting is planned for the afternoon of March 9 during Heli-Expo in Dallas. The main panel charged with the work is the S-12 Helicopter Powerplant Committee; it is to receive input from the S-16 Turbine Engine Inlet Flow Distortion Committee.
Feix said the outcome of the committees’ work could be SAE-sanctioned recommended practices. The FAA can accept recommended practices as methods of compliance with its regulatory requirements.
The FAA asked SAE to tackle the assignment after months of wrangling with IBF manufacturers Aerometals and Donaldson Aerospace over whether installation of the devices meet regulatory safety requirements. Specifically, the agency questioned whether the manufacturers had adequately demonstrated that installation of their products stayed within limits for engine inlet distortion and power available from a helicopter’s engines.
The dispute arose despite the fact that most helicopter IBFs have been installed under supplemental type certificates (STCs) issued by the FAA or other aviation authorities to verify the safety of the installations.
Citing the need to “ensure the safe and standardized installations of IBFs in rotorcraft,” the agency last February proposed a new policy statement on IBF installations and new regulatory guidance and compliance methods for obtaining supplemental type certificates for them.
The proposed changes led to an uproar at the FAA Town Hall during last year's Heli-Expo and a subsequent meeting near the agency’s Rotorcraft Directorate in Fort Worth, Texas, attended by 50 or so industry representatives. Many of those attendees echoed the comments of Aerometals and Donaldson executives that, after more than two decades of service with more than 7,000 units that have accumulated 20 million-plus flight hours in which no accident had been attributed to IBFs, the devices are demonstrably safe.
“There have been zero accidents,” said Aerometals President Rex Kamphefner at the time. “Where, I ask you, is the safety problem?”
FAA Rotorcraft Directorate Manager Lance Gant in September 2016 offered a suggestion that a new committee including IBF manufacturers and helicopter OEMs might develop alternatives to the agency’s proposed changes.
SAE’s Feix said it typically can take 18 to 24 months for new recommended practices to be developed, reviewed and approved through the organization's multi-layered voting process. But the engagement of SAE already may be smoothing the IBF debate. Aerometals’ Symon said that company now has IBF certification projects moving forward with the FAA.