On July 31, 2017, about 1745 mountain standard time, a Columbia LC41-550FG airplane, N8725, sustained minor damage when it was involved in an incident near Chandler, Arizona. The private pilot and three passengers were uninjured. The aircraft was operated as a Title 14 Code of Federal Regulations Part 91 business flight.
The pilot reported that during the descent from 9,500 ft mean sea level, the oil pressure indication dropped rapidly, followed by a decrease in manifold pressure. He subsequently declared an emergency with the tower controller at Chandler Municipal Airport (CHD), requested landing clearance. The pilot saw smoke originating from the engine, and shortly after the engine began to run extremely rough and then lost power. The pilot activated the emergency locator transmitter and initiated a forced landing to a field that resulted in minor damage.
A Federal Aviation Administration inspector conducted an examination of the airplane at the accident site. The lower side of the fuselage was covered in oil. The upper engine cowling was removed, and a hole was visible on the top side of the engine crankcase.
The airplane was relocated to a secure facility and the engine was removed from the airframe. The accessory section of the engine was covered in residual oil. The exhaust crossover tube revealed burned oil deposits across its length. The starter adapter drive pulley was found loose on its shaft. After further examination and disassembly of the starter adapter, the pulley hardware (nut and washer) were tight, however, the pulley was found loose on the starter shaft, which allowed the pulley to wobble. The pulley was removed and found to be damaged. The ball bearing, shaft seal, spacer and shaft were also damaged. The starter adapter assembly, including aftermarket pulley and belt were installed directly above the rear exhaust cross-over pipe which exhibited the baked-on engine oil. The examination of the engine revealed multiple failed connecting rods which were found consistent with oil starvation.
The Continental Motors Critical Service Bulletin (CSB 02-2C) provides instructions for an inspection of starter adapters for indications of oil leakage at the shaft oil seal. The bulletin states that compliance should be within the next 10 hours of operation for engines and starter adapters with less than 500 hours total time. Additionally, inspect affected engines and starter adapters every 25 hours of operation until accumulation of 500 hours total time. A warning within the bulletin states, “loss of engine lubrication may result in internal engine damage and subsequent engine failure.”
The airplane’s maintenance documents provided no indication that CSB 02-2C was complied with or that when the starter adapter drive belt was last adjusted. The last annual inspection was completed on June 21, 2017, and the airplane had accumulated 4.2 hours of operation since that inspection.