Van Nuys reported overcast at 1100, while the helicopter was at 1400, so he was still in the clouds. He would have been trying to go lower to get into VFR conditions. I guess he forgot that he was also flying toward an area of elevated terrain. It’s easy for me to say that he should have stayed IFR. Many pilots have done what he did. I don’t think any lived to tell about it, though.
I wonder if that was the regular pilot or if he’d flown that route before.
ATC may have screwed up by giving him a Special VFR Clearance.
https://pilotworkshop.com/tips/special_vfr_clearance/
He was following I-5 to the Van Nuys area then was cleared to follow 118 for awhile (never was over 118 proper) then was following the 101 towards Thousand Oaks (his destination I hear) when he veered off 101 at Los Virgines Road...mistook Los Virgines Road for Hwy. 101 maybe?
Track:
https://www.flightradar24.com/data/aircraft/n72ex#23a8271e
ATC: https://youtu.be/B0pQfgi9ZqU
Photos: https://www.helis.com/database/cn/51524/
Had been repainted a lighter blue/white scheme since the dark “Nike” scheme in these photos.
I don’t know the avionics of his bird, but I can’t help to think that he would have had terrain. All accounts seem to indicate a mechanical failure or loss of lift due to turning. (I’m also a chopper pilot). It’s like a parachutist who turns and the lift isn’t straight up but horizontal, so he falls quicker. Helicopters do the same thing.