By Susan Caminiti. When Micron Technology CEO Steve Appleton, 51, died in a plane crash on Feb. 3, the company not only lost its long-time leader, it experienced a stock price drop amid concerns about who would take the helm at the memory chip maker. The company’s board of directors swiftly announced that COO D. Mark Durcan would replace Appleton. But what if—as is so often the case with small businesses—there isn’t another qualified person waiting in the wings should tragedy strike at...