Finsterwalder CLICK-LOCK and T-LOCK buckles in the chest strap
DHV flying ban for many harnesses, several of which are not listed specifically below.
The DHV have grounded a large number of harnesses with chest straps using automatic T-lock and Click-lock buckles (HSi10) made by the company, Finsterwalder Charly. This concerns numerous harnesses made by Advance, Ava-Sports, Apco, Finsterwalder & Charly, Karpofly, Sky Paragliders, Skytrekking, Sol and Woody Valley, as well as some harnesses used for paramotoring.
The DHV have issued a Safety Notice, legally binding in Germany, to stop using harnesses thus equipped, at the latest, four years after their production or, to be more precise, since the final control when they left the factory. The owners of such harnesses are asked to contact the manufacturer.
This knee jerk reaction was no doubt, triggered by the fatal accident involving a Polish pilot at the beginning of May in addition to another incident during a SAT. In both cases, the automatic Click-lock buckles apparently opened under load. The T-locks haven’t been involved in an incident yet but their design is identical to the Click-locks.
The problem, according to the DHV, is the repetitive loading on these buckles or, more precisely, the cycles of diagonal load/unload which can, over a long time, wear out this piece of equipment. As a consequence, opening unexpectedly when loaded diagonally, can’t be ruled out.
This only applies to the chest buckles, which are loaded and unloaded, unlike the buckles on the thigh straps which have hardly any pressure on them in flight. For buckles which are subjected to static, non cyclical load, the manufacturer has specified a 10 year life (the normal length of time in Germany).
It is thought (and special care should be taken with this information which isn’t in the DHV statement), that the risk could in particular concern harnesses with ‘Get-Up’ type fastenings with two waist buckles. In flight they are regularly loaded and then unloaded. If one of them releases, there is a high risk of falling out.
An English version of the DHV’s statement can be read here:
In the past three months, there have been two incidents involving older paraglider harnesses equipped with CLICK-LOCK buckles (HSi10) in the chest strap. The buckles had opened unintentionally during flight while they were under load. In one of the cases this happened during a SAT maneuver (spreading of the chest strap due to the pilot resting on the riser), in the other case the reason was presumably the load applied by the body weight of the pilot who was hanging only in the leg straps.
Finsterwalder has conducted a technical investigation and found the following: The hooks of the metal tongue can wear out through the frequent diagonal load changes the chest strap is subject to. This might lead to decreased load capacity and – in the case of sufficiently high diagonal load transmission – the buckle might open unintentionally.
As a consequence of this finding, Finsterwalder has limited the respective buckles’ service time to 4 years if they are used in paraglider chest straps. The harness manufacturers have already been informed accordingly.
To date, there have been no unintentional openings of T-LOCK buckles. However, since their mechanism resembles that of CLICK-LOCK buckles, the problem is likely to be the same.
Finsterwalder calls on all owners of harnesses equipped with CLICK-LOCKs (HSi10) or T-LOCKs in the chest strap to determine their buckles’ previous usage time by checking the routine test date on the sample inspection label. If this date indicates a usage time of more than 4 years, the harness is not airworthy for now and may not be used for flying anymore. Affected owners should contact their harness manufacturer.
The service time limitation applies only to CLICK-LOCK and T-LOCK buckles that are used in paraglider chest straps. When used for applications where only static loads are involved, the CLICK-LOCK and T-LOCK buckles’ service life is 10 years.
The following harness manufacturers have used the mentioned buckles in one or more of their models: Advance, AVA Sport, APCO, Finsterwalder & Charly, KARPO FLY, SKY Paragliders, SkyTrekking, SOL, Woody Valley. Besides the buckles are used in paramotor harnesses of several manufacturers.