Teetering heads are not allowed to fly at less than 1g
point five "g" on the Huey and Kiowa. From Huey manual,
8-53. Low G Maneuvers.
WARNING - Intentional flight below +0.5 G is prohibited.
WARNING - Abrupt inputs of flight controls cause excessive main rotor flapping, which may result in mast bumping and must be avoided.
a. Because of mission requirements, it may be necessary to rapidly lower the nose of the helicopter. At moderate to high airspeeds, It becomes increasingly easier to approach zero or negative load factors by abrupt forward cyclic inputs. The helicopter may exhibit a tendency to roll to the right-simultaneously with the forward cyclic Input.
b. Such things as sideslip, weight and location of external stores and airspeed will affect the seventy of the right roll. Variances In gross weight longitudinal cg, and rotor rpm may affect the roll characteristics The right roll occurs throughout the normal operating airspeed range and becomes more violent at progressively lower load factors. When it is necessary in rapidly lower the nose of the helicopter, it is essential that the pilot monitor changes In roll attitude as the cyclic is moved forward.
c. If the flight envelope is inadvertently exceeded, causing a low "G" condition and right roll, move cyclic aft to return rotor to positive thrust condition, then roll level, continuing flight if mast bumping has not occurred.