The animal is thought to have climbed out of a hold mid- flight and spooked the crew and passengers.
The passengers panicked and ran towards the cockpit, and the forward shift in weight may have caused the plane to plummet to the ground on August 25, 2010 and crash into a house close to Bandundu airport, according to testimony during an inquest, reported the Times UK.
Only one person survived the crash as did the crocodile, though it was killed with machetes by rescuers sifting through the plane's wreckage.
The co-pilot, Chris Wilson, was British. Authorities holding an inquest in the UK on Friday heard that the crocodile might have been the reason for the crash.
The reptile, which measured up to three feet in length, was brought on board in a sports bag so that it could be sold.
Wilson's father, Rob, said there was a video of the crocodile being taken onto the plane.
"They think it may have frightened the cabin crew member and she ran forward, with the other passengers following. The weight shift caused by the panic may have affected the plane causing it to nose dive or stall," a UK coroner said.
Other considered causes for the crash included engine failure and a fuel shortage.