Investigators have been unable to find the flight data and voice recorders from the site of a plane crash in Nigeria that killed 117 people in October, the head of the investigating team said on Sunday.
Angus Ozoka said the failure to locate the "black boxes" meant it would take longer to determine what caused the Boeing 737, operated by Nigerian airline Bellview, to crash shortly after take-off from Lagos on October 22, killing everyone on board.
"We were not able to recover the black boxes -- flight data recorder or cockpit voice recorder -- although we found some strips of the casing," Ozoka told a news conference at Lagos Airport.
The wreckage recovered from the 4 metre (13 feet) deep crater near the village of Lissa, about 30 km (18.6 miles) from Lagos in Ogun state, has been taken to an air force base for further examination.
Ozoka said the investigation would continue in Nigeria and in the United States. A US team has been helping the inquiry.
The aircraft took off from Lagos for the capital Abuja during an intense electrical storm and experts have said evidence so far points to a lightning strike as the possible cause for the crash, though there has been no official confirmation.
Bellview, popular with government officials and expatriates, had previously had a clean safety record. The 24-year-old Boeing had received a clean bill of health from inspectors in February, the airline has said.
The air transport sector in Africa's most populous country has grown dramatically in the past decade, but most of the fleet is second-hand and at least 20 years old.
