Who says?
Both Shell Twotter crashes in Nigeria could not be blamed on the basic design of the aircraft, unless you expect a Dornier 328 to just hit a mountain and bounce off unharmed or to cut its way through an F27 like a hot knife through butter, both things the Twotter is sadly incapable of.
The number of hours racked up on the Dorniers was too little to say much about its safety record I think, while the program itself seems to have croaked mostly on the basis that it was too expensive, something that should only have come as a surprise to some Shell so-called manager stupid or greedy enough to have chosen a new and relatively untried type of aircraft over one that had an established track record, the Dornier 328 over the Dash 8.
Thank God Shell didn't repeat that blunder when they chose the EC-155, eh?