FAA Federal Aviation Regulations (FARS, 14 CFR)

If any of the engine main rotating systems will continue to rotate after the engine is shutdown for any reason while in flight, and where means to prevent that continued rotation are not provided; then any continued rotation during the maximum period of flight, and in the flight conditions expected to occur with that engine inoperative, must not result in any condition described in §33.75 (a) through (c).

[Doc. No. 28107, 61 FR 28433, June 4, 1996]