In two reported cases the release line of a FreeX-Control towing hook has become tangled in the release-pin and prevented disengagement! Upon examination it has been determined that the plastic casing between the release pin and the wire release mechanism had suffered shrinkage of more than 1mm, and that the release line had become caught at this point.
In addition it has been determined that the band attached to the rubber protector on the release handle had also suffered shrinkage, and was forcing the release pin too far forward. Through this, when attaching the tow line it was then possible for the release line to slide behind the release pin and so become damaged.
The release pin should not be longer that the streched out band attached to it. The release line must lie directly on the pin and not on its plastic casing! Towing hooks with damaged release mechanisms must be repaired before further use. Please observe the Airworthiness warning of 1999-09-16 where this problem was first identified.