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Warning Spiral dive hangglider MastR - M DHV 01-0444-09

SubjectSpiral dive hangglider MastR - M DHV 01-0444-09

Do not exceed flight operation limits! Check Batten clips!

On 9th of March 2015 a testpilot, on behalf of the DHV, performed a spiral dive with 50% VG setting and strongly pulled in base bar to re-enact a video documented accident. While clearly exceeding the operating limitations given by the manufacturer „maximum bank angle 60 degree, maximum speed 90 km/h“ a stable spiral occurred, which could not be recovered by the pilot. He needed to activate the rescue parachute. The reason for the appearance of the stable spiral dive is not doubtless clear yet. The video documentation of the testflight shows, that during the spiral dive, batten clips on the inside of the turn open, as on the previous accident.

The behaviour of this glider type in a spiral dive had been tested during the certification. In this process no batten clips opened and the Spiral could be recovered normally. On grounds of the accident the DHV had undertaken video documented testflights last year, but not with strongly pulled in base bar as in the accident. Thereby no anomaly occurred. Also the manufacturer Icaro 2000 presented a video documentation where a spiral with intentionally opened batten clips could be recovered without problems. However, in this case the spiral dive was also not flown with strongly pulled in base bar.

In July 2014 , as a result of an accident investigation, the DHV requested in the DHV-Info Nr.188: „Check Batten clips!“ and at the same time addressed the manufacturer of batten clips, Airborne. In the meantime Airborne presented limiting values for the holding force of the batten clips (which are used in most hang glider types). Airborne points out: If the batten clips are operated the wrong way when beeing opened they wear out. To much tension can damage them as well.

The following limiting value for the holding force must not be undercut: Vertical application of force at the end of the clip 8,6 kg.

Irrespective of this, in general it counts that by exceeding the operating limits, stated in the owners manual by the manufacturer, uncontrollable flight attitudes/situations can occur.

Wolfgang Kaiser
ICARO paragliders - Fly & more GmbH
Hochriesstraße 1, D-83126 Flintsbach
Tel. +49(0)8034 - 909 700, Fax 909 701