N369JR

HISTORY OF FLIGHT

On June 7, 1996, at 1145 eastern daylight time, a Beech V35B, N369JR, loss engine power during departure from Carroll County Regional Airport in Westminster, Maryland. The commercial pilot, the sole occupant and registered owner of the airplane, was not injured. The airplane sustained substantial damage during the forced landing. Visual meteorological conditions prevailed and no flight plan was filed. The flight, conducted under 14 CFR Part 91, had an intended destination of Washington County Regional Airport in Hagerstown, Maryland.

The pilot stated that this was the first flight of the day for the airplane. He stated that the preflight, taxi, and engine runup all seemed normal. The pilot stated that he took off on runway 16, retracted the landing gear and climbed up to approximately 2000 feet mean sea level on a westerly heading. The pilot acknowledged that it was at this time that he reduced engine RPM. He stated that the power decrease was too large for the small input he had made on the engine controls and was associated with a rough engine. The pilot then stated that this was followed by the loss of engine sounds. After lowering the nose of the airplane, the pilot indicated that he changed fuel tanks, checked individual magnetos and turned back towards the airport. It was at this time that the pilot believed he heard a knock and shortly thereafter, the propeller stopped windmilling.

The pilot wrote that his attention was now focused on choosing a field in which to land. The pilot stated that he altered his selection of a field due to some trees and when he had his alternate field made he selected the gear down. The pilot stated that the gear did not have time to extend and the airplane slide approximately 300 feet on mowed hay.

AIRCRAFT INFORMATION

The engine on the airplane was a Teledyne Continental IO-520-BA, serial number 232701-R. The engine was a factory rebuilt engine manufactured in 1981 and had 772 hours Time Since Rebuilt. There was less than five hours on the engine since the last annual inspection.

WRECKAGE AND IMPACT INFORMATION

The initial examination of the airplane's engine was conducted by the Federal Aviation Administration Inspector and the engine manufacturer Air Safety Investigator. They confirmed rotation and compression on all cylinders; both magnetos generated a spark when the propeller was rotated. The fuel pump coupling was found sheared and thought to be the source for the loss of power. Due to the persistence of the FAA Inspector on an inclination that something was not right, the engine manufacturer Air Safety Investigator, the National Transportation Safety Board Air Safety Investigator along with the FAA Inspector reexamined the airplane's engine. It was during this reexamination that the discontinuity of the engine's crank shaft was discovered. Subsequently, the engine was removed from the airplane and shipped for teardown.

ADDITIONAL INFORMATION

In September 1992, the engine manufacturer with the FAA approval, released a Mandatory Service Bulletin. This MSB dealt with the replacement of a certain make of crankshafts and identified all the affected engines. It went on to state that sufficient field service data had been accumulated and that it would be prudent to require replacement of these crankshafts. It stated that compliance should be at next overhaul or whenever the crankshaft was removed or made accessible for any reason.

This engine crankshaft was of the make mentioned in the MSB. The inspection of the crankshaft during the teardown, found that it was broken at the number seven short cheek. A subsurface origin was found and progression of the fracture was in fatigue until overload and separation occurred. The engine was a factory rebuilt engine manufactured in 6-2-81. All cylinder spot putty was intact on all cylinder hold down nuts indicating the engine had not been opened since factory rebuild.