Oi Che -
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The climb segments come from Part 25, which is a certification standard for the airplane. As an example for the 737, your first segment must be a "positive climb" (no gradient specified) until your gear is retracted. Then start your second segment, 2.4% until 400 feet above your liftoff reference point where you reduce engine to max continuous thrust. then start your third/final segment at 1.2% required, until 1,500 above liftoff reference, where you can accelerate and retract flaps.
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Your SID 3.3% is not a certification segment, it is a climb required to clear obstacles for the departure route. Obvious if you lost an engine at V1, you could not comply with that SID.
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Receba um abraço do seu amigo.
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Happy contrails