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state of the water may influence the choice of
landing direction more than the direction of the wind.
In calm or light winds, takeoffs usually are made in the
same direction as the flow of the current, but landings
may be made either with or against the flow of the current,
depending on a variety of factors. For example,
on a narrow river with a relatively fast current, the
speed of the current is often more significant than wind
direction, and the need to maintain control of the seaplane
at taxi speed after the landing run may present
more challenges than the landing itself. It is imperative
that even an experienced seaplane pilot obtain detailed
information about such operations before attempting
them for the first time. Often the best source of information
is local pilots with comprehensive knowledge
of the techniques that work best in specific locations
and conditions.
GLASSY WATER LANDING
Flat, calm, glassy water certainly looks inviting and
may give the pilot a false sense of safety. By its nature,
glassy water indicates no wind, so there are no concerns
about which direction to land, no crosswind to
consider, no weathervaning, and obviously no rough
water. Unfortunately, both the visual and the physical
characteristics of glassy water hold potential hazards
for complacent pilots. Consequently, this surface condition
is frequently more dangerous than it appears for
a landing seaplane.
The visual aspects of glassy water make it difficult to
judge the seaplane’s height above the water. The lack
of surface features can make accurate depth perception
very difficult, even for experienced seaplane
pilots. Without adequate knowledge of the seaplane’s
Centrifugal
Force
Skidding
Force
Figure 6-5. A downwind arc is one way to compensate for a
crosswind.
Ch 06.qxd 8/25/04 10:45 AM Page 6-5
6-6
height above the surface, the pilot may flare too high or
too low. Either case can lead to an upset. If the seaplane
flares too high and stalls, it will pitch down, very likely
hitting the water with the bows of the floats and flipping
over. If the pilot flares too late or not at all, the
seaplane may fly into the water at relatively high speed,
landing on the float bows, driving them underwater and
flipping the seaplane. [Figure 6-6]
Besides the lack of surface features, the smooth,
reflecting surface can lead to confusing illusions as
clouds or shore features are reproduced in stunning
detail and full color. When the water is crystal clear and
glassy, the surface itself is invisible, and pilots may
inadvertently judge height by using the bottom of the
lake as a reference, rather than the water surface.
The lack of surface texture also presents a physical
characteristic that adds slightly to the risk of glassy
water landings. A nice smooth touchdown can result in
faster deceleration than expected, for the same reason
that the floats seem to stick to the surface during glassy
water takeoffs: there is less turbulence and fewer air
bubbles between the float bottoms and the water, which
effectively increases the wetted surface area of the
floats and causes higher drag forces. Naturally, this
sudden extra drag at touchdown tends to pull the nose
down, but if the pilot is expecting it and maintains the
planing attitude with appropriate back pressure, the
tendency is easily controlled and presents no problem.
There are some simple ways to overcome the visual
illusions and increase safety during glassy water landings.
Perhaps the simplest is to land near the shoreline,
using the features along the shore to gauge altitude. Be
certain that the water is sufficiently deep and free of
obstructions by performing a careful inspection from a
safe altitude. Another technique is to make the final
approach over land, crossing the shoreline at the lowest
possible safe altitude so that a reliable height reference
is maintained to within a few feet of the water surface.
When adequate visual references are not available,
make glassy water landings by establishing a stable
descent in the landing attitude at a rate that will provide
a positive, but not excessive, contact with the
water. Recognize the need for this type of landing in
ample time to set up the proper final approach. Always
perform glassy water landings with power. Perform a
normal approach, but prepare as though intending to
land at an altitude well above the surface. For example,
in a situation where a current altimeter setting is
not available and there are few visual cues, this altitude
　
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