This September 2008 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
Aircraft: Sadler Vampire. Injuries: 1 Minor. Location: Findlay, Ohio. Aircraft damage: Substantial.
What reportedly happened: The experimental amateur-built airplane was a prototype for Light Sport Aircraft certification. The accident happened during a flight test, which was being done at the request of the engine manufacturer. The test pilot had not received flight instruction or a checkout in the airplane. He also had no training or experience in aircraft flight testing. Prior to the accident flight, he performed two taxi tests during which he performed short hops on the runway to get familiar with the aerodynamic forces that would be encountered during takeoff and landing. The engine temperature was reported as normal during this time. The pilot then attempted a takeoff for a flight that was to remain in the airport traffic pattern. Just after takeoff the plane lost all engine power. The pilot attempted an engine restart without success. He executed a forced landing into a quarry located about half a mile from the departure end of the runway.
An examination of the reduction drive assembly needle roller bearing sidewall revealed a combination of wear and high temperatures leading to over-stress. Wear marks on the separated cage sidewall and the presence of metallic debris suggested impingement of the rollers on the sidewall during engine operation. Heat tinting of the outer raceway in the vicinity of the failed sidewall and the cam that served as the inner raceway was also noted. The needle bearing malfunction could be attributed to misalignment of the needle bearing and insufficient lubrication.
Probable cause: A total loss of engine power due to the failure of the reduction drive assembly as a result of excessive wear and high temperatures. The pilot’s lack of total experience in the airplane and the unsuitable terrain for a forced landing were factors.
For more information: NTSB.gov