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Deutscher Hängegleiterverband e.V.

DHV

Safety Journal

Parachutal stall accident

On Sunday 23rd July 06 a serious accident occurred to a Swiss paraglider pilot while flying from the Ebenalp in Switzerland. An experienced pilot was surprised by weather developments and flew through a rain shower. Her paraglider (DHV class 1-2) then entered a parachutal stall, which the pilot was not able to recover from using the standard methods (pulling the A-risers or accelerating with the speed bar). The pilot decided to attempt to land on a steep grassy slope while still in the parachutal stall. Shortly before impact (2m above the ground) the canopy entered a full stall, probably due to brake input. On impact the pilot suffered severe spinal injuries, thankfully with no neurological side effects.

It is known that some canopies have an increased tendency to enter parachutal stalls when wet. It is also known that there are big differences in the reactions of canopies from different manufacturers – some fly quite normally when wet, as has often been reported by cross country pilots caught in rain showers, whereas others report that minimal rain is sufficient to increase the danger of parachutal stalls on their canopies. Last year a school pilot was injured after crash landing in a parachutal stall, after having only flown for a few minutes in very light rain. In the current accident report from Switzerland, again, the rain fall was described as minimal, and the rescue helpers reported the canopy being dry on their arrival at the scene.

Winch tow pilots are particularly sensitised to this problem – a canopy which has become damp merely from lying on wet grass may well demonstrate a higher tendency to enter parachutal stalls.

A pattern indicating which types of canopies are more prone to this problem has not been identified. Occurrences of parachutal stall when wet have been reported throughout all classes. It would appear that older canopies, where the cloth can absorb water more readily may be at higher risk, however, the current accident occurred with a new glider.

It is most important that pilots recognise this potential danger source and act accordingly. Should a pilot fly through rain, the area should be left as quickly as possible, the brakes must only be used sparingly, manoeuvres which cause the canopy to fly with a greater angle-of-attack (e.g. Big ears) should be avoided, and should the conditions safely permit it, the glider should be flown accelerated by using the speed bar.

If a landing while in a parachutal stall is unavoidable, it is most important that the brakes are not used at all, even though this goes against all normal pilot instincts when approaching the ground. When a canopy flies in a parachutal stall, applying a few centimetres of brake may result in the canopy going into an uncontrollable full stall.

Should a parachutal stall occur when flying at sufficient height for a reserve deployment, this should be considered. The advantage here, is that the reserve descent is more stable, and not prone to either stalling or diving as in a parachutal stall descent. The sink velocity of a reserve descent is generally lower than that of a glider in parachutal stall providing the reserve canopy is of the correct size for the pilot. The Swiss pilot reported a sink velocity of -6m/s for her canopy while in parachutal stall.

Karl Slezak

Safety Officer DHV

 

Competition performance with certified safety?

Almost 10 years ago, in response to worrying accident statistics, the DHV started a campaign for flying class 1 and 1-2 paragliders. As a result, the market share of these canopies has increased ten-fold.

Stress-free and safe flying has never been as easy as with current paragliders in these classes, and performance has improved to such a degree as to still satisfy the wishes of some of the most ambitious pilots.

The numbers of performance-intermediate and high-performance gliders produced had declined and a corresponding reduction in market-share has been a direct result of pilots enhanced safety-consciousness.

Through the increased interest in the Online Contest (OLC) and the introduction of DHV class 2-3 competitions, the DHV now registers an increasing number of higher classified canopies, and is concerned about developments in the DHV 2-3 class.

Test criteria for Gütesiegel certification in this class are pushed to their limits, in particular when testing asymmetric and front collapses. The newest class 2-3 canopies conform to the certification test criteria (e.g. asymmetric collapse: 75% of the leading edge along a 45 degree collapse line), however, test pilots report that slight differences (e.g. to the collapse line angle) may often lead to significantly more demanding canopy reactions.

In the air, paragliders of all classes often demonstrate more demanding reactions to „real“ collapses than when collapses are induced in a test program. Pilots must appreciate that this means real-life canopy reactions of new class 2-3 canopies may well exceed the test criteria for this class, or even those for a class 3 glider.

A very realistic approach has been taken by Nova for their new Tycoon paraglider: in printed advertisements it is clearly stated how high the expectations on the pilot lie for this canopy. Gin Gliders also highlight the high-performance character of their new Boomerang Sport, and the consequences this has for the pilot.

The DHV recommendations for pilots of class 2-3 canopies read as follows: Prerequisites for flying class 2-3 paragliders: pilots must demonstrate a maximum of expertise, immediate reactions in all situations, should have many years of flying-practice and an recognisable over-average talent for flying.

Please take these recommendations to heart, when considering upgrading to a new glider.

Toni Bender states in the Nova Tycoon advertisements, that all pilots who do not really have the necessary experience, are better off training intensively on a lower classified canopy.

I agree wholeheartedly.

Karl Slezak

DHV-Sicherheitsreferent


Increase of Glider safety at Hangliding european and Worldchampionships

DHV proposal  unananimously accepted by the FAI. The DHV´s proposal, to ask for a minimum of technical tests as entry criteria for FAI Kategory 1 hangliding competitions, has been accepted unananimously by the CIVL/FAI plenum after a constructive discussion. This is a further step to enhance safety at FAI competitions and to provide a fairand equal enty basis for the participants. Last year the FAI/CIVL  introduced several new standards: safety director, mandatory safety meeting, maximum wind speed, etc.
A CIVL working group, consisting of  technical experts, pilots and manufacturers, will work out the details of the new regulations to enhance glider safety. At the European championships in Croatia, glider inspections, will be performed, but without consequences to the pilots. Finalisation is planned for the 2007 season. In paragliding competitions analog  technical requirements have been standard for a long time. Every paraglider has to be positively load tested.

Safety Notice to the DHV 26.02.2003 

Swing - Paraglider - Mistral 2.22

The following safety notice relates only to the SWING Mistral 2.22 glider.

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.

We are therefore asking all Mistral 2.22 – pilots to take extra care when using their gliders, particularly in the situations described in (a) to (d) below.

All equipment which has been affected so far shows the following unusual behaviour:

1) Deteriorating launch behaviour
2) Stable deep stall, especially when "big ears" are used
3) Poor transition to normal flight after a B stall
4) Shorter braking distance

The following factors can contribute to the tendency to deep stall and were found in almost all cases brought to our attention:

(a) Weather conditions with high air density
(b) Dry air conditions
(c) Flying where the temperature is around or less than 0° C.
(d) Take-off weight is at the lower end of the weight range
(e) On "big ears"

Causes

Gliders generally come close to the stall limit in the situations above ((a) to (d)) since in these cases drag values increase greatly. It appears that a pilot could go beyond this stall limit on the Mistral 2.22 in unfavourable conditions.

Materials not at fault:

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.

Safety Check

The advice to pilots which is given below on how to check their gliders was determined in agreement with the DHV and should be carried out before the next flight. Further investigations should only be carried out by Swing.

Procedure:

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.

Swing Tel: +49 (0) 8141 3 27 78 88

Reminder: tips on what to do in a deep stall:

- Don't apply too much brake
- Consider using the speed system
- Consider pulling down the A-risers

Best wishes

The Swing Team


Carabiners break during Flight

Facts, reasons and consequences. A summary from Reiner Brunn.

 

Recently the word got around that some automatic crabiners for paragliding harnesses opened inadvertantly.

Here is some useful information, resulting from an accident investigation by the DHV/OeAeC technical Department, referring to a recent happening. Details... (Loading takes time, because of many pictures)