TM 55-1520-228-10
5-10 Change 14
SECTION VI. MANEUVERING
5-22. AEROBATIC MANEUVERS.
Aerobatic maneuvers are prohibited. Aerobatic flight is
defined to be any intentional maneuver involving an
abrupt change in aircraft attitude, an abnormal attitude,
pitch angel greater than $30_ or roll angles greater than
60_, or abnormal acceleration not necessary for normal
flight.
5-23. CONTROL MOVEMENTS.
CAUTION
For gross weights greater than 3000
lbs and density altitudes greater than
sea level, the directional control
margin may be significantly reduced
while hovering in winds from the
right greater than 20 knots or for right
sideward flight at speeds greater
than 20 knots.
Abrupt control movements, including rapid and repeti-
tive anti-torque pedal reversals are prohibited to avoid
excessive stresses in the structure. This restriction in no
way limits normal control application.
5-24. HOVERING LIMITATIONS.
Ten percent of total pedal travel, full right to full left, is
considered adequate for safe control. The rearward air-
speed limit is 30 knots and sideward limit is 35 knots
except that control is marginal for certain combinations
of relative wind velocity and azimuth angles (measured
clockwise from the nose of the helicopter). See Chapter
8, for a description of the marginal wind velocity and azi-
muth angles.
5-25. FLIGHT RESTRICTIONS AT LOW
“G’S”.
Flight at less than +0.5g is prohibited.
5-26. FLIGHT RESTRICTIONS FOR PRAC-
TICE AUTOROTATION LANDINGS. (Figure
5-4.)
Practice autorotation landings may be accomplished
subject to the following limitations.
a. A qualified OH-58A/C IP must be in position to
take control of the aircraft.
b. Reported surface winds must not exceed 20
knots.
c. Surface crosswind component must not exceed
10 knots. Wind gust spread must not exceed 10 knots.
d. Touchdown rotor RPM must not be less than
64%.
e. Ground speed at touchdown should be approxi-
mately 5 knots.
f. Airspeed during glide shall not be less than that
established for minimum rate of descent.
CAUTION
In any event, relatively long ground
runs with the collective up, or any
tendency to float for long distance
prior to skid contact should be
avoided. If vibrations are
encountered after touchdown
immediate lowering of the collective
is recommended.
g. Upon ground contact, collective pitch must be
reduced smoothly to bottom stop without delay while
maintaining cyclic pitch near center position. Application
of aft cyclic should be avoided.
h. Touchdown autorotations downwind are prohib-
ited.
5-27. DELETED.
5-28. FLIGHT RESTRICTION FOR HIGH
POWER.
NOTE
In aircraft equipped with IR exhaust
stacks, rate of climb in excess of 1000
ft/min may result in divergent aircraft
pitch oscillation which can reach 20 to
30 degree attitudes. This divergence
can be alleviated by either increasing
airspeed during steady climbs or de-
creasing rate of climb. Climb rates in ex-
cess of 1000 ft/min should be avoided.
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