Wow, very dramatic! I'm not familiar with the Cobra's performance but I believe VRS, or as the Army refers to it: settling with power, is certainly a prime candidate.
I'm noticing a difference in what the Army teaches and what the FAA does, so I'm not trying to insult anyone's intelligence but we are taught three things must exist for settling with power to occur: rate of descent of at least 300fpm, insufficient power to arrest descent, and slow airspeed (below ETL). Based on how he was maneuvering, I'd imagine he had a lot of power applied and when he went to turn, his true airspeed would've dropped off. His rate of descent as he turned certainly picked up so maybe VRS!
Retreating blade stall generally occurs at higher airspeeds, though, again, I'm not familiar with the Cobra's performance specs. In counter-clockwise rotating rotorcraft (I think all US-made combat helos) RBS results in a left roll and pitch, which seems to be the opposite of what happened here.
Wow, very dramatic! I'm not familiar with the Cobra's performance but I believe VRS, or as the Army refers to it: settling with power, is certainly a prime candidate.
I'm noticing a difference in what the Army teaches and what the FAA does, so I'm not trying to insult anyone's intelligence but we are taught three things must exist for settling with power to occur: rate of descent of at least 300fpm, insufficient power to arrest descent, and slow airspeed (below ETL). Based on how he was maneuvering, I'd imagine he had a lot of power applied and when he went to turn, his true airspeed would've dropped off. His rate of descent as he turned certainly picked up so maybe VRS!
Retreating blade stall generally occurs at higher airspeeds, though, again, I'm not familiar with the Cobra's performance specs. In counter-clockwise rotating rotorcraft (I think all US-made combat helos) RBS results in a left roll and pitch, which seems to be the opposite of what happened here.