Pilot error was to blame for the 2007 crash in Cameroon of a Kenya Airways flight in which 114 people died, an official investigation has concluded. A report says the Boeing 737 took off during a storm without clearance from air traffic control in Douala. The pilot was given misleading instructions about how to stabilise the aircraft which then crashed upside down into a swamp, it says. The Kenyan authorities said lessons had been learned and safety improved. The investigation was carried out by the authorities in Cameroon in conjunction with Kenya Airways At a press conference in Nairobi following the release of the report, Kenya Airways sought to cast doubt over the degree to which human error was to blame. "We have some reservations on the report, particularly touching on the probable cause of the accident," Titus Naikuni, Kenya Airways chief executive, told the BBC. 'Too shy' The BBC's Will Ross in Nairobi says the findings make uncomfortable reading for Kenya Airways, which is partly owned by the Dutch Airline KLM. Flight recorders reveal that just 90 seconds after take-off the plane had rolled almost 90 degrees to the right. When the captain noticed the problem he said, "We are crashing." The first officer then mistakenly told the pilot to turn right, before correcting himself and saying, "Captain, left, left, left." Nine seconds later the plane crashed into the swamp, disintegrating on impact. It took rescue workers about 36 hours to find the wreckage. The report identified the age difference between the 52-year-old pilot and the 23-year-old first officer as a contributing factor, reports the Associated Press - one of whose reporters was killed in the crash. The findings speculate that the young first officer was too shy to tell the more senior pilot about the plane's problems after take-off. In January 2000 another Kenya Airways plane crashed in Ivory Coast killing more than 150 passengers. Despite these accidents the airline is widely considered one of the best in sub-Saharan Africa, our correspondent says.