Comoros is an archipelago of three main islands about 2,900 kilometres south of Yemen, between Africa's southeastern coast and Madagascar. ((CBC))

A French navy captain said Thursday his vessel has detected the black boxes of a Yemenia Airways plane that crashed last month near the Comoros Islands.

Comoran authorities, meanwhile, are still investigating the cause of the June 30 crash.

A woman from Ottawa was among the 152 victims of Flight 626, which crashed into the Indian Ocean between the southeastern African coast and Madagascar while en route from the Yemeni capital of San'a to Comoros. A 12-year-old girl was the only known survivor.

Capt. Marc Reina told The Associated Press from the French island of Reunion that his crew has found where the black boxes lie beneath the Indian Ocean and mapped the area off the Comoran coast.

He said that underwater robots should begin operating in August to retrieve the black boxes, which lie too deep for divers to reach.

The plane's cockpit voice and flight data recorders could help explain why it crashed as it tried to land in heavy winds.