Search on for clues in crash

Egypt has sent a robot submarine to join the hunt for an EgyptAir plane which crashed in some of the deepest waters of the Mediterranean Sea with 66 people on board, President Abdel Fattah al-Sisi said yesterday.

Ships and planes scouring the sea north of Alexandria have found body parts, personal belongings and debris from the Airbus 320, but are still trying to locate the black box recorders that could shed light on the cause of Thursday's crash.

Sisi said that underwater equipment from Egypt's offshore oil industry was being brought in to help the search.

"They have a submarine that can reach 3,000 metres under water," he said in a televised speech. "It moved today in the direction of the plane crash site because we are working hard to salvage the black boxes."

An oil ministry source said Sisi was referring to a robot submarine used mostly to maintain offshore oil rigs. It was not clear whether the vessel would be able to help locate the black boxes, or would be used in later stages of the operation.

Air crash investigation experts say the search teams have around 30 days to listen for pings sent out once every second from beacons attached to the two black boxes. At this stage of the search they would typically use acoustic hydrophones, bringing in more advanced robots later to scan the seabed and retrieve any objects once they have been found.