The investigations launched on Boeing's (BA) Dreamliner by regulators on both sides of the world center on two distinctly different searches. Depending on how it works out, the results could have a resounding effect on the company. Japanese regulators are investigating the batteries themselves and whether the planes received faulty batteries. Contrarily, U.S. regulators are focusing on the complex fly-by-wire systems. If the problem is simply a bad battery batch, BA needs just to replace the defective ones with new ones. However, should the problem be more systemic, the costs to Boeing could be tremendous.