"The mechanic revealed to the NTSB IIC during the interview that he felt that the crankshaft gear bolts had failed as a result of a sudden engine stoppage when the airplane collided head-on with a tree. As such, the failure of the crankshaft gear bolts was not the cause of the accident, however, was as a result of the accident. The mechanic further opined that he felt there was nothing wrong with the engine, and that what probably precipitated the loss of engine power was carburetor ice. He added that the accident pilot told him earlier that morning that he had to wait about 30 minutes or so for the fog to lift so he could take off."
Tom - you almost killed your customer because you forgot to tighten some bolts. But it wasn't just a few bolts. We sure are glad you have said you are not accepting new customers. Your attitude is insane - the bolts failed because of fatigue, that is a completely different failure mechanism than sudden stoppage. Obviously you won't accept this either. It is your fault. You fckd up.
Shame on you. And thank whoever you believe in, that the poor pilot and passenger are alive. And that they won't use the legal system to take everything you have ever owned to recoup their suffering.
"The engine had an oil filter and adapter installed"
"The original engine oil screen remained installed, despite the fact that the engine was equipped with an oil filter. When the oil screen was removed, a significant amount of contaminates consistent with metallic material as well as a significant amount of unidentified black colored substance was observed."
^ Well done signing off that engine.
" It was noted that there was black sealant applied to the crankcase halves mating surfaces, and there was no silk thread noted on the crankcase halve mating surfaces. It was also noted that the black sealant material was found in several of the oil galleys"
^ Well done overhauling it. Jezzes!
"The four crankshaft gear bolts all exhibited overstress fractures in their threaded portion. Two of the four bolts, referred to as bolts #1 and #2, exhibited gross plastic deformation in the shank portion. Bolt #1 had broken free of the safety wire, and bolt #2 had a portion of safety wire still attached. Both of these two bolts exhibited fractures consistent with overstress. The remaining two bolts, referred to as bolts #3 and #4, remained safety wired to each other, and did not exhibit gross plastic deformation. These two bolts exhibited flat fractures and crack arrest marks consistent with fatigue fractures.
The bolt holes in the crankshaft gear had become elongated. This effect was less pronounced on the face of the gear that would have mated to the crankshaft, and more pronounced on the opposing face. The crankshaft gear teeth appeared to be well formed, and did not exhibit any irregularities or uneven wear.
The crankshaft gear dowel pin was fractured, and partially missing. The portion that was submitted to the laboratory contained a flat fracture surface. Examination of the fracture surface using a stereo microscope revealed crack arrest marks and ratchet marks consistent with a fatigue fracture. There were three prominent ratchet marks indicating a fatigue fracture with multiple origins. Examination of the body of the dowel pin revealed wear marks on one side."
No reason to not tighten the bolts all the way with a torque wrench. 80ish hours after OH, I'm guessing they were finger tight = forgotten to put on properly at all. Scary.
I mean hello. I'm sorry to be critical, but he built an engine that was nowhere near airworthy, and almost killed people doing it.
I am so very happy Tom isn't accepting new customers. This is dangerous. I hope they take his A&P/IA away.
