14 CFR § 29.59

The takeoff path extends from the point of commencement of the takeoff procedure to a point at which the rotorcraft is 1,000 feet above the takeoff surface and compliance with § 29.67(a)(2) is shown. In addition—

The takeoff path must remain clear of the height-velocity envelope established in accordance with § 29.87;

The rotorcraft must be flown to the engine failure point; at which point, the critical engine must be made inoperative and remain inoperative for the rest of the takeoff;

After the critical engine is made inoperative, the rotorcraft must continue to the takeoff decision point, and then attain VTOSS;

Only primary controls may be used while attaining VTOSS and while establishing a positive rate of climb. Secondary controls that are located on the primary controls may be used after a positive rate of climb and VTOSS are established but in no case less than 3 seconds after the critical engine is made inoperative; and

After attaining VTOSS and a positive rate of a climb, the landing gear may be retracted.

During the takeoff path determination made in accordance with paragraph (a) of this section and after attaining VTOSS and a positive rate of climb, the climb must be continued at a speed as close as practicable to, but not less than, VTOSS until the rotorcraft is 200 feet above the takeoff surface. During this interval, the climb performance must meet or exceed that required by § 29.67(a)(1).

During the continued takeoff, the rotorcraft shall not descend below 15 feet above the takeoff surface when the takeoff decision point is above 15 feet.

From 200 feet above the takeoff surface, the rotorcraft takeoff path must be level or positive until a height 1,000 feet above the takeoff surface is attained with not less than the rate of climb required by § 29.67(a)(2). Any secondary or auxiliary control may be used after attaining 200 feet above the takeoff surface.

Takeoff distance will be determined in accordance with § 29.61.