The FAA is seeking public comment on a proposal to amend one engine-inoperative (OEI) rating definitions and type certification standards for 30-sec, 2-min, and 30-min OEI ratings for rotorcraft turbine engines.
This proposal calls for revising the ratings’ standards to reflect "recent analyses of the ratings’ usage and lessons learned from completed engine certifications and service experience," the agency said. It aims to harmonize FAA type certification standards for these ratings with the requirements of the European Aviation Safety Agency and with proposed requirements for Transport Canada. Comments on the proposal are due by Aug. 2.
The OEI rating powers provide rotorcraft with higher than takeoff and maximum continuous rating powers during takeoff, cruise, and landing when one or more engines of a multi-engine rotorcraft fails or is shut down.
These OEI rating powers enable the rotorcraft to continue safe flight until it reaches a suitable landing site. Federal Aviation Regulations Part 33 prescribes airworthiness standards for 30-sec, 2-min, 2.5-min, 30-min, and other OEI ratings for the issuance of type certificates for rotorcraft turbine engines.
All OEI ratings are optional ratings that engine manufacturers may select from those specified in FAR Part 33.7. The Certifications Specifications — Engines prescribe corresponding airworthiness standards of the European Aviation Safety Agency for these ratings.
While these standards are similar, they differ in certain regulations. The FAA said it wants to minimize those differences because "non-uniform standards impose a regulatory hardship on applicants seeking certification under both sets of standards in the form of additional costs and delays in the time required for certification."