WELLINGTON, July 20 (Xinhua) -- New Zealand’s Civil Aviation Authority (CAA) on Saturday grounded 21 aircraft over safety concerns.

CAA Director Graeme Harris suspended the airworthiness certificates of all 21 Gippsland GA8 Airvan aircraft currently operating in New Zealand.

The suspension follows the death of nine people in a crash of a GA8 Airvan aircraft after leaving the runway in Sweden on July 14.

The CAA director said he “cannot compromise when I have information that indicates any unacceptable risk,” while acknowledging any inconvenience this grounding will cause and its significant commercial impact.

The Australian civil aviation regulator also grounded the planes and sent a technical specialist to Sweden to assist the crash investigation as the GA8 is Australian manufactured.

Based on information coming out of the initial investigation into the crash, it appears that the airplane, at 4,000 meters altitude, suffered structural failure, however, at this time, the root cause of the accident cannot be confirmed, Harris said, adding that the grounding was effective immediately and would be continuously reviewed as further information becomes available from Sweden and Australia.

There are 10 aviation operators affected by the action, with fleet sizes ranging from one to up to four of these aircraft. The GA8 is primarily used in New Zealand on tourist flightseeing operations, according to CAA.