https://www.verticalmag.com/news/ntsb-releases-more-details-s-97-raider-accident/
NTSB releases more details on S-97 Raider accident
https://dms.ntsb.gov/public/62000-62499/62323/624201.pdf
NTSB releases more details on S-97 Raider accident
Сам документ:The Sikorsky S-97 Raider prototype destroyed by a hard landing in 2017 suffered extreme roll oscillations as the aircraft’s flight control software transitioned from ground to air modes during takeoff, according to the National Transportation Safety Board’s (NTSB’s) newly-released factual report.
https://dms.ntsb.gov/public/62000-62499/62323/624201.pdf