Nairobi — Cameroonian officials have recovered the cockpit voice recorder from the wreckage of the Kenya Airways Flight KQ 507 that crashed into a swamp in Douala last month.

Kenya Airways chief executive Titus Naikuni said the device was recovered on Friday at 2.25 pm Douala time.

"The cockpit voice recorder was found on the accident site on Friday, June 15," Cameroonian Transport minister Dakole Daissala said.

"Measures are under way to take it to the Transportation Safety Board laboratory in Ottawa, Canada, so it can be deciphered," he said in a statement.

The cockpit voice recorder will assist the investigators to establish the last conversation between the pilots before the plane plunged into the swamp minutes after takeoff.

The six-month-old Boeing 737-800 crashed close to Douala Airport shortly after taking off for Nairobi in stormy weather at around midnight on May 4-5.

A preliminary investigation into the crash has found no evidence of mechanical failure, Cameroon authorities said in a statement posted on Friday on a government Web site. The Cameroon Civil Aviation Authority said a full report of what led to the crash will take up to 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.

Rescuers had already retrieved a first "black box", the in-flight data recorder, but the voice recorder should contain the last minutes of conversation between the pilot and co-pilot. Efforts to retrieve it had been hampered by heavy rains.