A preliminary plane crash investigation has not revealed evidence of mechanical failure.
The Kenya Airways flight nose-dived into a swamp in the West African country less than two minutes after taking off from Cameroon's commercial capital of Douala on a stormy night in early May. The Boeing 737-800 was bound for Kenya.
The Cameroon Civil Aviation Authority said a full report of what led to the May 5 crash will take as long as a year.
The preliminary review of the flight data recorder showed no evidence of a mechanical malfunction, the statement said. In addition, the investigation found that all crew members were sufficiently trained and certified according to expected aviation guidelines.
Though the flight was delayed about an hour because of thunderstorms and heavy rain, the report suggested that conditions had cleared by the time the flight took off.
Pilots from two other airlines said they waited longer to take off because they were concerned about the weather.
The report, issued June 11, also said the Kenya Airways jetliner reached 3,000 feet before nose-diving sharply at a 45 degree angle "for undetermined reasons." The plane disintegrated on impact.
It took about two days for Cameroonian authorities to find the crash site, as reports from locals suggested the plane might have crashed hundreds of kilometers south and the body of the jetliner sank into the mud of the swampy forest.
The report says that investigators plan to also review the performance of the flight crew and consider if there were any regulatory oversights.
The U.S. National Transportation Safety Board is assisting Cameroon in the investigation, along with aviation authorities from Kenya and Canada.
Recovery operations are ongoing at the crash site. The cockpit voice recorder has still not been found.
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