Under the right circumstances, these can kill you. In this case it did. Nothing beats the original equipment threaded oil plug!
https://data.ntsb.gov/carol-repgen/api/ ... 103266/pdf
The pilot was en route to his home airport. While approaching the airport, the pilot transmitted over the common traffic advisory frequency that he had an emergency and then that he would be making a straight-in landing due to an in-flight. Witnesses stated that the airplane’s engine sounded rough and was sputtering before a “pop” sound was heard. The airplane appeared to be on fire with trailing smoke. The airplane then banked right and left, and turned toward the airport while losing altitude quickly. The airplane then struck the tops of trees before it impacted the ground. Security camera video footage confirmed the witness observations that there was an inflight fire, showed that the fire appeared to be near the engine, and that blue gray smoke consistent with an oil-fed fire was trailing from the airplane.
The oil quick drain on the engine oil sump was found to be leaking, even though it was in the closed position. Examination of the oil quick drain revealed that it was discolored and that the O-rings were melted, indicating that the oil quick drain had been exposed to a high heat condition. Further examination of the area around the oil quick drain revealed the presence of soot on the bottom of the oil sump downstream of the No. 2 cylinder where the engine’s left side exhaust pipe was separated from the exhaust collector. Additional examination of the exhaust system indicated that the left exhaust pipe was a slip fit design and that no exhaust pipe clamp was present. This evidence indicated that the source of the thermal distress event was most likely an exhaust system leak that impinged on the oil quick drain, melting the O rings and resulting in the oil draining from the engine and subsequently igniting. A review of the operating temperatures associated with the engine indicated that the exhaust gas temperature was hot enough to exceed the upper limit of the temperature specifications of the oil quick drain and was also hot enough to ignite the oil. This ultimately resulted in the in-flight fire and led to the pilot’s subsequent loss of airplane control.
