Скоростные вертолёты

https://www.verticalmag.com/news/ntsb-releases-more-details-s-97-raider-accident/
NTSB releases more details on S-97 Raider accident
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.
Сам документ:
https://dms.ntsb.gov/public/62000-62499/62323/624201.pdf