Accident Details
Shortly after takeoff, the pilot experienced a loss of power on the right engine. Attempting to return to the airport, the pilot determined he could not reach the runway and elected to land on a dirt field. During the approach, the aircraft flew under power lines in the flight path, and the pilot attempted to flare before impact with the terrain.
Engine Examination
The airplane was equipped with Teledyne Continental GTSIO-520 engines. Post-accident examination of the right engine revealed that all teeth on the starter adapter gear and several teeth on the crankshaft gear were missing. Multiple gear teeth and metal filings were found in the oil sump. The torsional damper-to-shaft gear woodruff key was sheared. The torsional damper underwent bench testing to determine damping time; consecutive tests averaged 6.9 seconds, whereas a new damper has a damping time range of 1.5 to 3.125 seconds. Metallurgical examination showed that 15 starter gear teeth and 11 crankshaft gear teeth were fractured near their root, with no indications of preexisting cracking. At least two starter gear teeth and several crankshaft gear teeth displayed spalling and wear at the pitch line.
Service History
On June 13, 1994, Teledyne Continental issued Mandatory Service Bulletin MSB94-4 addressing the possible failure of the starter adapter gear and/or crankshaft gear on GTSIO-520 and GIO-550 engines. A revision, MSB94-4G, was issued on October 31, 2005. The service bulletin called for inspection of the starter adapter viscous damper and shaft gear backlash every 100 hours of engine operation, and a visual inspection of the starter adapter shaft and crankshaft gear teeth for spalling, pitting, and wear every 400 hours. The Federal Aviation Administration (FAA) issued Airworthiness Directive (AD) 2005-20-04, effective November 1, 2005, requiring compliance with the Teledyne Continental Mandatory Service Bulletin. Maintenance records showed that the mandatory service bulletin was complied with when the right engine was overhauled and installed in March 2001. However, there was no indication in the maintenance records that either the mandatory service bulletin or the AD had been complied with since installation. The engine had a total time of 541.9 hours at the time of the accident.
Pilot Actions
The pilot did not follow the published emergency procedures.
Probable Cause
Maintenance personnel failed to comply with an Airworthiness Directive which resulted in the total failure of the starter adapter gear teeth and the crankshaft gear teeth and the pilot failed to follow the published emergency procedures. Contributing to the accident were the low altitude at which the loss of power occurred, the power lines, and the unsuitable terrain which prevented the pilot from adequately flaring the airplane and resulted in the subsequent hard landing.