It has come to the attention of SWING that there have been occasional incidents when this model has shown an increased tendency to deep stall in certain situations. All gliders sent to us for inspection came within the permissible tolerance levels. Nor did these gliders differ in any other respects from the sample provided to DHV.
Gliders generally come close to the stall limit in certain situations when drag values increase greatly (more information can be found at http://www.dhv.de/typo/Safety_Journal.833.0.html ).
It appears that a pilot could go beyond this stall limit on the Mistral 2.22 in unfavourable conditions. The problem cannot be put down to defects in the materials (e.g. increased air permeability) since newer gliders with good air permeability values are also affected.
As a precaution, Swing is therefore taking the following safety measures as agreed with the DHV: The owner of the glider must determine whether the Mistral 2.22 shows any tendency to hang back when launched on a level training area in still conditions (not a reverse launch). This should be tried at least five times before reaching any conclusion.
If it is clear that its launch behaviour is poor or if there are any other peculiarities, the glider should not be flown and SWING should be contacted. The pilot must check the glider before it is next flown. Further investigations should only be carried out by Swing.
Günter Wöhrl, Geschäftsführer Fa. Swing
Tel: +49 (0)8141 3 27 78 88