Relatives of people who died when a no-frills Thai airline One-Two-Go crashed last September are preparing to sue for $400 million in compensation in the United States. The families have also asked Thai authorities to file criminal charges against the CEO of the airline.   Ribbeck Law Chartered, a Chicago law firm representing many of the foreign victims' relatives, urged the Thai authorities to release their investigation into the crash to throw light on the reasons for the crash. A preliminary official inquiry blamed pilot error. One-Two-Go's MD-82 jetliner crashed on Sept. 16 last year when attempting to land on Phuket in heavy rain and strong winds, leaving 89 dead and 41 injured.