Accident Summary
On 12 April 1984 at 0919 local time, a SA 315B Lama helicopter, registration HB-XDI, operated by Air Zermatt AG, was involved in an accident during a hover at an altitude of 1600 m near Zermatt, Switzerland. The helicopter was attempting to pick up an external load consisting of a crate of window panes measuring approximately 300x300x30 cm and weighing between 400 and 450 kg. The load had been placed on a delivery van, secured to a frame installed on the loading platform.
Sequence of Events
Flight helpers A and B prepared the load for transport. They unhooked the crate from the frame and attached long slings. When the load was ready, helper A informed the operations center, who advised that the helicopter would arrive in about one minute. Helper A stood on the loading platform of the van, while helper B climbed down and positioned himself on the ground, intending to stabilize the load during lift-off. Helper A instructed B to remain on the platform to avoid snagging, but B kept his position.
The pilot approached from the north due to local conditions. Helper A turned away from B to focus on the helicopter. As helper A reached for the load to attach it to the helicopter hook, the crate tipped over, fell from the platform, and landed on helper B. The pilot immediately pulled the helicopter away. Helper A saw the load had tipped and expected the pilot to return to lift it, but the pilot pointed downward, revealing that B was trapped. The load then slid completely off the platform, covering B. Helper A and three workers lifted the crate, allowing B to crawl out. B was transported to the hospital in Visp and later transferred to a hospital in Bern, where he died on 30 April 1984 from his severe injuries.
Findings
The pilot held a valid commercial helicopter pilot license and had 6975 total flight hours, with 148 hours in the preceding 90 days and 68 hours on the accident helicopter type in that period. The helicopter was airworthy and properly certified. Flight helper A was employed by Air Zermatt AG. Flight helper B had been employed as a flight helper since 2 April 1984, having come to Zermatt for several years and showing great interest in flight operations; he was on leave from military service in Germany. The accident was reported to the accident investigation bureau on 16 April 1984. No other witnesses could confirm the sequence of commands given by helper A to B. The investigation noted that B was not at his assigned location but in a dangerous position behind the load, and that A was focused on the approaching helicopter. The report emphasized the importance of ground organization and clear task assignment.
Cause
The accident was attributed to the unexpected tipping of the load under the influence of rotor downwash and the dangerous position of the inadequately trained flight helper.