NEW ORLEANS -- Transocean employees should have done more to detect signs of trouble before the company's drilling rig exploded in the Gulf of Mexico in 2010, killing 11 workers and triggering the nation's worst offshore oil spill, the company's chief executive testified Tuesday.But the Swiss-based drilling company's own investigation of the disaster didn't find any mistakes beyond the rig floor, Transocean CEO Steven Newman said.He testified on the 14th day of a trial designed to determine the causes of BP's well blowout and to assign fault to the companies involved."I think we had a good system in place," said Newman, who testified that Transocean agreed in January to plead guilty to a criminal charge of violating the Clean Water Act because its rig workers on the Deepwater Horizon played a role in botching a crucial safety test before the blowout."Do I blame the crew? Do I wish the crew would have done more?" he replied to questions from his firm's attorney. "Absolutely. I am not sure that that's the same emotional content as blame."Newman, however, said BP was ultimately responsibility for deciding how to perform the safety test and determining if it was successful.Two BP rig supervisors, Robert Kaluza and Donald Vidrine, are charged with manslaughter in the 11 rig workers' deaths and await a separate trial.An indictment last year accused Kaluza and Vidrine of disregarding abnormally high pressure readings during the safety test.No Transocean employees have been charged with crimes, but the company pleaded guilty to the misdemeanor charge in February and agreed to pay $1.4 billion in criminal and civil penalties as part of a settlement with the Justice Department.BP's internal investigation of the blowout also spared its own upper-level managers from any blame. Instead, the London-based oil giant issued a report that outlined a series of mistakes by rig workers and faulted decisions by other companies.Newman touted the company's safety culture, saying any rig worker is empowered to call a halt to a drilling operation. If a worker sees any cause for concern, he said, "You not only have the right but the obligation to call a timeout.""Safety is one of our core values," Newman said.Elsewhere, 2009 was a rough year for Transocean. Newman said the company temporarily suspended operations on its entire fleet of rigs after four workers were killed in separate incidents within a 92-day period that year."I don't think there's any other conclusion you can draw than we had a problem," Newman said during cross-examination by plaintiffs' attorney Robert Cunningham.The deaths, coupled with an increasing number of "high-potential incidents," prompted Newman to order an independent review of the company's safety management system."I think sometimes the difference between a high-potential incident and an actual injury is nothing more than luck," Newman said, citing an example of rig equipment that falls harmlessly to the deck instead of hitting somebody."Are you telling us that control of high-potential incidents such as what occurred on the Deepwater Horizon is a matter of luck?" Cunningham asked. "Is that Transocean's safety philosophy?"