French investigators looking into the Air France crash over the Atlantic a month ago have delivered their first report.They said they were still far from establishing what caused the Airbus 330 travelling from Rio de Janeiro to Paris to plunge into the Atlantic on June 1 with 228 people on board. There were no survivors. Chief investigator Alain Bouillard said they were able to rule out any possibility that the plane broke up in mid-air. “It seems the plane hit the surface of the water in the line of flight with a strong vertical acceleration,” he added. Investigators said the search would continue for the plane’s black boxes but hopes of finding them are fading fast as they only emit signals 30 days after a crash. 51 bodies and hundreds of pieces of wreckage have been recovered. No distress call was received from the plane, but 24 automated messages were sent in the final minutes before it came down. There has been speculation about the plane’s airspeed sensors, the so-called “pitot” probes, which provided inconsistent readings in the final minutes before the plane came down. However, investigators said that while they might have been one of the elements they were not the cause of the accident.