34
Section 07
Dangerous situations and extreme flying
move forward making the glider form a
U-shape. Again, recovery is by light
symmetrical braking on both sides, but
care must be taken that both wing ends
return to normal flight evenly.
Types of stall
When a paraglider flies through the air,
a laminar and turbulent boundary layer
is created. Extremely dangerous flight
configurations can result if the laminar
boundary layer is interrupted, with
practically the entire airflow along the
top surface braking away. This happens
in particular when the angle of attack is
too great.
There are three different types of stall
in paragliding.
Deep stall
Paragliders can go into a deep stall for a
variety of reasons: brake lines too short
(no slack), old or damaged glider
material which therefore has increased
level of permeability, altered trim/line
length
and
changes
to
profile
characteristics caused by moisture
(e.g. flying in rain). Paragliders have a
particular tendency to stall if the wing-
loading is too low.
In a deep stall, the airflow from the
front reduces and the glider goes into a
stable flight attitude without forward
momentum. The paraglider sinks almost
vertically at 4-5m/s and there is
noticeably less flight noise.
Recovery
Remain in an upright position and push
the A- and B-risers in the direction you
are flying, so as to shorten them by 5-
10cm.
If you have a speed system, you can also
use it to accelerate, so that the glider
goes into a normal flying position from
the deep stall.
After you have landed, the glider and the
length of the lines must be checked.
Full stall
With a full stall, the lift-generating
airflow over the glider breaks away
completely or nearly completely.
It is triggered when the maximum
possible angle of attack is exceeded. The
most common cause is going below the
minimum speed or flying near the
minimum speed combined with the
effects of turbulence.
In full stall, the paraglider loses its
forwards travel, surges backwards and
deflates. If the brakes are held down,
the canopy comes up over the pilot
again. The result is an almost vertical
descent with a sink rate of approx.
8m/s.
Recovery
Fully release the brakes within 3
seconds (count 21, 22, 23). If the
brakes are released too slowly, the
paraglider may spin. The spin stops
automatically when the brakes are
released completely.
WARNING
Full stall and spin are manoeuvres
which can be fatal if recovery is not
correct. These manoeuvres should
therefore be avoided. However, it is
important to learn how to recognise
the indications that a glider is about
to stall so that you can take
immediate action to prevent it.