AirDesign SUSI 4 Manuel D'instructions page 60

We strongly advise against flying in rainy conditions. Normally the SUSI 4 does not show a
tendency for a deep stall. If it happens that you get into rainfall, we recommend not to perform
a B-stall or Big Ears. The best is to leave the rain as soon as possible, and to fly with both brakes
released, or even accelerated, as this reduces the risk of a deep stall. (The available brake
travel before entering a deep stall may be reduced significantly.)
If a deep stall should happen release it according to instructions above.
n. Rapid decent manoeuvres
i. Spiral
The spiral dive is an effective way of making a fast descent. During the spiral dive the pilot and
glider will experience strong centrifugal forces which strain the glider. As such it should be
considered an extreme manoeuvre. Due to the rapid height loss during a spiral, pilots must
always take care that they have sufficient altitude before initiating the manoeuvre and that the
airspace is free around the pilot.
Initiation: Weight shift and smoothly pull on one brake (the same side you are weight shifting
into) so the glider goes from a normal 360-degree turn into a steep turn and from there into a
spiral dive. Once established in the spiral the descent rate and bank angle can be controlled
with weight shift and the releasing or pulling of inner brake. As the glider banks in front of the
pilot maintain the spiral by keeping the brake pressure constant, at this point weight-shift can
be neutralised. Descent is controlled by pulling more on the inner brake. A slight pull on the
outside brake helps to keep the glider stable.
Recovery: The SUSI 4 recovers from a spiral spontaneously as soon as the brakes are released
and weight shift returns to neutral. To exit, allow the spiral to slow down for a turn or two by
slowly releasing the inner brake. Once the glider starts to exit the spiral, control your descent
rate and bank angle with weight shift and the outer and/or inner brake to prevent any strong
climbs out of spiral. Always finish a spiral dive at a safe altitude.
The SUSI 4 does not show any tendency for a stable spiral. That means the glider does not
remain in spiral after releasing the brakes. If the glider should, in rare cases, remain in a stable
spiral the pilot should first weight-shift to the outside and then brake slowly more on the
outside.
ATTENTION: In a stable spiral the G-forces are very high. Be aware that it may therefore
require considerable more input and effort to recover from this state.
ATTENTION: When exiting a spiral too fast the conversion of energy may result in the glider
climbing quickly and entering its own turbulence. This may cause the glider to collapse. We
advise that you allow the SUSI 4 to exit from the spiral dive in a controlled manner.
You should take care to use only moderate spirals so as not to put unnecessary load on you
and your lines.
IMPORTANT SATEFY NOTICE! A pilot who is dehydrated and/or not accustomed to spiralling
can lose consciousness during a steep spiral dive!
ii. B-line stall
This is an effective way of making a moderate to rapid descent but doesn't allow any forward
speed.
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