Rated 2 1/2-minute OEI power

Rated 2 1/2-minute OEI power, with respect to rotorcraft turbine engines, means the approved brake horsepower developed under static conditions at specified altitudes and temperatures within the operating limitations established for the engine under part 33 of this chapter for periods of use no longer than 2 1/2 minutes each after the failure or shutdown of one engine of a multiengine rotorcraft.

Source: 14 CFR Federal Aviation Regulations 1