MAC PARA Chronos, User Manual

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RAPID DESCENT TECHNIQUES
B-line stalls:
As there is a lot of load on the “B’s” we do not recommend using B-Stall as a descent
technique under power. Performing B-Line stalls on any glider weakens the fabric by
putting unnecessary strain on the lines. It could deform the quality of airfoils and weaken
it.
To induce a B-line stall without power, symmetrically pull down slowly on both B-risers,
until the canopy folds (parallel to its long axis). The airflow over the top surface is almost
fully detached and the canopy enters a vertical descent flight mode without forward
movement. Further pulling of the B-risers reduces the surface area more and increases
the sink rate (Up to 8 m/s). Pulling too far down or too rapidly may cause a frontal
horseshoe to form. To exit from this flight mode release the B-risers at first rapidly but
then gently (1 sec). The canopy surges forward re-attaching the airflow over the top
glider surface and resumes normal flight. When the B-risers are released, the brakes
should not be activated. This will give the canopy the chance to gain speed and resume
normal flight. On exit from a B-line stall on no account just release the B-straps, as this
can cause overloading on B row attachment points. If canopy does not recover apply
both brakes gently to recover or pull the A-risers, until the canopy regains forward
speed.
Summary:
For all extreme manoeuvres and rapid descents please note:

First practise manoeuvres with an instructor during safety training.

Before inducing any manoeuvre the pilot must check that there are no other
airspace users below him.

During the manoeuvre you must have the canopy within your view.