A consortium of 10 automakers led by Toyota Motor Corp plans to hire an independent engineering firm and a former top U.S. auto safety regulator to investigate a rash of problems with air bags supplied by Japan's Takata Corp , the group said on Wednesday. The carmakers want a forensic engineering firm "to address the technical issues with Takata air bag inflators," Toyota spokeswoman Julie Hamp said in a statement on behalf of the group, which refers to itself as the joint initiative.