Stability: general.
CFR · 2024-01-01 · US · Title 14
The rotorcraft must be able to be flown, without undue pilot fatigue or strain, in any normal maneuver for a period of time as long as that expected in normal operation. At least three landings and takeoffs must be made during this demonstration.
official document · source cfr-2024 · id 14:§ 29.171