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inexperienced pilot may choose to initiate a slight
forward movement when taking off into or landing
from a hover. This guards against undesirable
backward or sideward drift during takeoff or landing.
With smooth water conditions, the usual tendency is to
hover too high because the outward-flowing ripples
from the rotorwash gives the pilot the sensation of
being in a bowl and descending.
TAKEOFF
A float equipped helicopter can perform a normal
takeoff from a hover or directly from the water. If there
is insufficient power available for a normal takeoff, a
running takeoff from a slow forward taxi may be an
option. However, remember that water creates drag, so
with insufficient power, a running takeoff may not be
possible either.
The preferred method for taking off from water is to
move forward into translational lift without pausing to
hover after leaving the water. This type of takeoff is
similar to a normal takeoff from the surface.
A normal takeoff from a hover over water is similar to
the same type of takeoff over a hard surface. A
common problem is poor judgment of altitude and rate
of acceleration, which causes the pilot to increase speed
without an increase in altitude. This causes the
helicopter to enter the high speed portion of the
height/velocity diagram, reducing the probability of a
successful autorotation in the event of an engine
failure. Also, be aware of possible restricted visibility
during takeoff from water spray produced by the
rotors. To help alleviate these problem areas, as the
helicopter begins to move forward, use reference
points some distance in front of the helicopter.
Over water, ground effect is reduced from the absorption
of energy in the downwash. This increases the
power required to hover and with other factors may
exceed the power available. When this occurs, perform
a slow taxi to a takeoff to take advantage of the
translational lift produced from the forward motion.
Remember, translational lift is also affected by any
wind that is present. Apply sufficient collective pitch
to keep the floats riding high or skimming the surface.
While skimming the surface, float drag increases
rapidly, and the takeoff must be executed promptly
since a further increase in speed, with the floats
plowing in the water, is likely to exceed the limit of aft
cyclic control or cause the floats to tuck under the
water. The speed at which the floats tuck under is the
maximum forward speed that can be attained and is
determined by the load and attitude of the helicopter.
Never lower the collective during this procedure
because doing so could bury the nose of the floats in
the water and possibly capsize the helicopter.
LANDING
Pilots performing glassy water landings may experience
some difficulty in determining their altitude
above the surface. The recommended procedure is to
continue an approach to the surface with a slow rate of
descent until making contact, avoiding any attempt to
hover. The helicopter’s downwash creates a
disturbance in the water as concentric ripples moving
away from the helicopter. Although this provides the
pilot with a visual reference, it may also cause the
sensation of moving backwards or descending rapidly.
A natural tendency is to apply too much collective
pitch in an attempt to halt the perceived descent. To
overcome the effects of these visual illusions, avoid
staring at the water near the helicopter and maintain
forward and downward movement until contacting the
water. When making approaches to a landing on a
large body of water when land areas or other fixed
objects are not visible, occasionally glance to either
side of the horizon to avoid stare-fixation. Another
technique some pilots use when fixed objects are not
available, and the water is glassy, is to make a low pass
over the area to create a disturbance on the surface.
This disturbance remains for a while giving the pilot a
reference to help determine distance.
When landing on water with a slight chop, bring the
helicopter to a hover and descend vertically with no
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horizontal movement. This procedure is similar to
landing on a hard surface.
Make a running landing on water when high density
altitude or a heavy load results in insufficient power to
hover. Perform this type of landing when sufficient
power is not available to reduce the speed to 5 knots or
less. When approaching with greater than 5 knots of
speed, hold a slight nose-high attitude to allow the aft
portion of the floats to plane. Maintain collective pitch
　
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