"Enstrom ... airframe is 30 years old ... 1000+ hours left on all major components ... flying in another 30 years."
Wow.
"... ex-NYA 107-IIs ... highest-time helicopter in the world."
Double wow.
"Does this mean that twin-rotors is the best?"
Must admit Dave, i'm hoping you're taking away the lesson that a good design is simple rugged and extremely reliable....
"...EMS AS365N1 ... doors very difficult to close in flight. "
As a structural engineer, this scared the hell outa me! I've been known to introduce "permanent set" into airframes myself, but i really don't like the idea of that sort of flexibility. Generally that means that fatigue cracks are ganging up, and that a serious failure is imminent...
Does make me wonder if some machines are operated beyond a safe service life, although i always find the idea of finite design life abhorent.
Mart