The aircraft departed Samburu at 08:30 for a 50-minute flight to Nairobi and climbed to an altitude 8500 feet. Along the route there was a heavy build up of stratus clouds with scattered cumulonimbus sprouting out of the top. The clouds seemed to extend from 2 000 feet up to 11 000 feet and more and the pilot decided to fly below the clouds and continue VFR. He then realized that the weather was deteriorating very rapidly and within the next minute or two the visibility had been reduced to a few yards. Realizing the proximity to the ground, the pilot applied full power and initiated a climb. A hill appeared ahead and the aircraft crashed into the trees in a nose-up attitude. PROBABLE CAUSE: “The probable cause of this accident was that the pilot flew VFR in IMC weather at a very low altitude, thereby flying blindly into a hill.”