A French vessel carrying specialist probes designed to detect black box pinger signals has arrived to the search area where an EgyptAir jet is believed to have crashed last week, sources on the investigation committee said on Friday.

A week after the Airbus A320 crashed with 66 people on board, including 30 Egyptians and 15 from France, investigators have no clear picture of its final moments.

Alseamar, a subsidiary of French industrial group Alcen, is providing equipment that includes three of its Detector-6000 systems, designed to pick up black-box pinger signals over long distances up to 5 km (3 miles), according to the company's website.

The French company will conduct a deepwater search in "four or five" areas within the 5 km search zone believed to contain the two black boxes, with the possibility of expanding the search zone should no signal be detected, the source said. - Reuters