SHUTTERSTOCK/HEIKO JUNGE/EPA-EFE
The accident
helicopter’s remains, pictured during an
NSIA examination in a hangar near Oslo, Norway, Sep. 12, 2019.
The Investigation The Norwegian Safety Investigation Authority (NSIA) report on the accident notes that the extent of aircraft damage made the investigation “challenging.” Except for the tail boom, the airframe was almost completely con- sumed by fire, and no data could be retrieved from any of the onboard electronic recording or monitoring devices or the mobile telephones found in the wreckage, which was confined to a small area on an east-facing slope just below the peak of Skoddevarre at an elevation of 301 m (988 ft.). Two exhaustive searches eventually recovered almost all components that survived the fire. Detailed examina- tion showed that the main and tail rotors were turning at the moment of impact and found no evidence of any in-flight failure. The distribution of the wreckage strongly suggested that the helicopter struck the ground in a shallow nose-low attitude with slight left roll at relatively low speeds, both horizontal and vertical. ADS-B and GPS tracking data showed that while the
ferry flight was straight and level, both sightseeing flights included “great variations in altitudes and speeds” suggestive of vigorous maneuvering over simi- lar points in the landscape, with climbs and descents in excess of 3,000 ft. per minute (fpm). The final position fix showed the helicopter less than 300 ft. above the mountaintop, descending at 3,072 fpm as airspeed increased from 125 to 135 kt. The aircraft was also close
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to maximum gross weight. Based in part on the precedent of 11 prior accidents cited in its report, the NSIA concluded that LN-OFU entered servo transparency at low altitude and struck the ground before its pilot could complete the recovery, and that the relatively low energy of the collision strongly suggested that without the fire, the accident would have been survivable.
The Aftermath
Airbus Helicopters made crash-resistant fuel systems standard equipment on all new AS350 helicopters deliv- ered after Oct. 1, 2019, and on Oct. 10 of that year issued a letter urging operators to retrofit the systems to all AS350, H125, and EC130 models. No airworthiness directive to that effect has yet been issued in either the United States or Europe, however. On Oct. 17, 2019, Coptersafety opened a Level D
AS350 flight simulator facility in Vantaa, Finland. Simulator sessions in the United States at American Eurocopter in Grand Prairie, Texas, following a 2011 Norwegian accident reproduced servo transparency to an extent described by the participating instructor as “FRIGHTENINGLY realistic! We entered an uncontrolled roll, banking further to the right. The controls ‘froze’ at the same time as the collective wanted to come down.” After reproducing the 2011 accident sequence, which began at 300 ft. agl, he wrote, “We were of course
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