Air France's CEO said Thursday that he is "not convinced" faulty speed monitors caused the crash of Flight 447, which went down on its way from Rio de Janeiro to Paris with 228 people aboard. Replacement external speed monitors - or Pitot tubes - for jet models of the same type as the crashed plane arrived three days before the fatal accident, Pierre-Henri Gourgeon told journalists. The manufacturer Airbus ordered the replacements on April 27 after pilots noted a loss of airspeed data in flight on Airbus A330 and A340 models. The incidents were "not catastrophic" and planes with the old Pitots are considered airworthy, Gourgeon said. "Because I am not convinced that the sensors are the cause of the accident, and we have said it, I had no need to issue a press release the day after the accident," Gourgeon added, responding to criticism that there was a lack of transparency. "It's perhaps because we spend too much time with the families and not enough the press that you say this," he told an association of aerospace journalists in Paris. Air France hopes that the plane's flight recorders will be recovered, but even without them examinations of the debris and bodies recovered from the crash are expected to shed new light on what happened when the plane crashed May 31, he said. "We will know much more, I think, after the autopsies allow us to better understand the technical causes of death and when the debris have been examined by experts," he said. "In a week there will be a little more information but the important point will be the recorders," Gourgeon added.