FAA Proposes Updates for Helicopter Certification Rules

 - November 1, 2017, 3:42 PM

The FAA is seeking comment on a notice of proposed rulemaking (NPRM) that would broadly update FAR Parts 27 and 29 that govern the certification standards for civil rotorcraft. Comments are due on or before Jan. 30, 2018. As proposed, the changes are designed to reduce or eliminate the need to obtain special condition approvals for the certification of new rotorcraft and incorporate requirements of equivalent level of safety (ELOS) findings and means of compliance (MOC) issue papers that the FAA has imposed/issued for improving certain design features.

According to the FAA, the proposed rule "would address these problem areas by updating those standards that cause unnecessary burdens in cost and time to both the FAA and the rotorcraft industry." While compliance with these proposed regulatory changes would continue to be shown by the same testing, analysis and inspections as in the current certification process, there would be a reduced burden through clarification of the safety requirements for the installed systems.

Sections of the current rotorcraft certification standards are technologically obsolete and the bureaucratic circumvention to the problem is overly burdensome, the FAA essentially acknowledged in the NPRM. "The FAA is proposing to update Parts 27 and 29 because the regulations were originally published in 1964 and revisions to the airworthiness standards have not kept pace with advances in technology for rotorcraft...In some cases, advancements in technology have rendered the regulations obsolete...Existing airworthiness standards are inadequate because they do not address increasing design complexity."

The current method of using special conditions, ELOS and MOC as a workaround negatively affects "FAA resources and the applicants' schedules for obtaining FAA approval for their products" the FAA noted, adding that updating the certification standards would reduce the regulatory "burden on both the FAA and industry."

The areas proposed to be addressed would include flight control automation (FAR 27.1329 and 29.1329) with regard to autopilot functionality; flight director systems (27.1335 and 29.1335); lithium-ion batteries (27.1353 and 29.1353); and powerplant instruments (27.1305 and 29.1305) to allow for synthesized power indicator; and to permit manipulating powerplant instruments to simulate OEI without damaging the engines (29.1305(b)(4)).

In two areas alone—flight guidance and control systems and engine displays—the proposed rules could eliminate considerable paperwork.

The FAA proposes to combine the requirements for automatic pilot and flight director systems into one rule. Currently, FAR 27.1329 and 29.1329 address automatic pilot systems while 27.1335 and 29.1335 cover flight director systems. The FAA notes, "Having these systems in separate rules that use different terminology has resulted in some confusion" and that "modern designs include both automatic pilot and flight director systems."

With regard to synthesized power indicators (SPI), the FAA notes that it already is virtually an industry standard. "Many rotorcraft manufacturers have started to incorporate [an SPI] that provides a single indicator of engine performance. This single value displayed to the pilot is generally presented as a percentage of the nearest engine limit. The continuously displayed SPI presents the calculated value to the flight crew on the primary flight displays along with a caption indicating the nearest engine limiting parameter that is being used for the SPI displayed calculation.

"Acceptable designs allow the pilot to monitor engine performance and trends. Technologies such as an SPI, which combine multiple indicators into one, cannot meet the requirements of the current rules. By allowing means other than dedicated indicators, the proposed changes would permit designs incorporating an SPI or similar concepts."

Eliminating 'Irrelevant' Distinctions 

The FAA also is proposing a more structured and repeatable method of failure analysis for complex and integrated systems in Part 27 aircraft and eliminating the distinction between single- and multi-engine aircraft for this purpose under FAR 27.1309. The agency explains, "This distinction is now irrelevant since current analysis tools for technologies and associated failure effects do not consider number of engines as required input." However, the proposed rule would "clarify the requirement to perform a proper failure analysis and also recognize that the severity of failures can vary."

In addition, the FAA wants to eliminate the distinction between Category A & B aircraft under FAR 29.1309 when it comes to evaluating the differences in the depth of evaluating failures of complex systems and equipment. "This distinction is now irrelevant since current analysis tools for technologies and associated failure effects do not differ between Category A and Category B," the FAA notes. "Although the effects of the failures may be different, the method for conducting the failure analysis is the same regardless of the operations evaluated."

The rules on isolating pilot instrument systems (FAR 29.1333 and Appendix B to Parts 27 and 29) from any other operating systems were promulgated before the advent of microprocessors and today's integrated systems and are therefore "no longer appropriate" given today's redundant technologies, the FAA adds. The agency proposes to revise § 29.1333(a) and section VIII(b)(5)(i) of Appendix B to Parts 27 and 29 to make them applicable only to pneumatic systems.

The FAA also is suggesting scrapping rules governing flight instrument display and design that are leftovers from the analog era. The agency made particular note of those dictating instrument green arcs, radial lines, Vne barber poles, and  fuel gauges and markings.