Robert Campbell is onto it. Haven't flown the 400, but from time on 100 series, on strips with loose gravel, composite blades need to be nursed. Damage on rear of blades was evidence of standing take-offs, while damage on front of blades showed evidence of too much reverse thrust. Power application with aircraft stationary can result in strong vortices reaching to ground level, even with a high wing aircraft.
Trick was rolling starts, and careful with reverse on landing, back to ground idle before aircraft slowed down too much.
Sorry about the thread drift, no bearing on Buffalo accident.
