The black boxes recovered from the wreckage of an Egyptair plane that crashed in the Mediterranean a month ago are badly damaged, meaning that extracting data will take considerable time, sources in the investigation committee said on Sunday according to dpa. The memory units in the cockpit voice recorder and the flight data recorder, which were recovered from the sea last week, both suffered "severe damage," the sources said. The damage is currently being evaluated to see whether experts in the Egyptian Ministry of Civil Aviation will be able to repair the units or whether they will have to be sent abroad, the sources added. Egyptair flight MS804 was en route from Paris to Cairo on May 19 when it crashed into the Mediterranean, some 290 kilometres north of the Egyptian coast, killing all 66 people on board. The sources said it would be impossible to extract the data from the two units - one of which records voices and sounds in the cockpit, while the other gathers technical data from the aircraft's equipment - before carrying out the repairs. Shakir Qallad, the former director of the Egyptian air accident investigation committee, said that the process of extracting the data could take "a long time, maybe weeks" in addition to the time needed to repair the units.