On February 3, 2019, at 1345 Pacific standard time, a Cessna 414, N414RS, experienced an inflight breakup over Yorba Linda, California, about 11 miles west of the departure airport Fullerton Municipal Airport (FUL), Fullerton, California. The pilot and four individuals on the ground sustained fatal injuries, two individuals on the ground sustained serious injuries and the airplane was destroyed. The airplane was registered to and operated by the private pilot as a 14 Code of Federal Regulations (CFR) Part 91 cross-country personal flight. Visual meteorological conditions (VMC) prevailed over the accident location, and no flight plan was filed. The flight departed at 1339, with a planned destination of Minden-Tahoe Airport (MEV), Minden, Nevada. Radar and audio communications data provided by the Federal Aviation Administration (FAA) revealed that after departing FUL, the pilot initiated a climbing left turn to the east. Visual meteorological conditions (VMC) existed at the departure airport, however, preliminary information indicated that the weather transitioned to instrument meteorological conditions (IMC) with precipitation, microburst and rain showers over the accident area. During the takeoff clearance, the FUL tower air traffic controller cautioned the pilot regarding deteriorating weather, about 4 miles east of FUL. Radar data showed that 5 1/2 minutes after takeoff, the airplane had climbed to an altitude of about 7,800 ft above ground level before it started a rapid descending right turn and subsequently impacted the ground. Numerous witnesses who were located near the accident site, saw the airplane exit the clouds at a high rate of descent before parts of the airplane started to break off. One witness reported that he, "observed an aircraft emerge from the overcast layer on a northwesterly heading with a nose down pitch of approximately 60 degrees, pointed directly at my location with no discernable movement. It remained in that attitude for approximately 4 to 5 seconds before initiating a high-speed dive recovery. Approaching the bottom of the recovery the aircraft began to roll to its right. As it did, the left horizontal stabilizer departed the aircraft, immediately followed by the remainder of the empennage. The left wing then appeared to shear off just outside of the number one (left) engine igniting the left wing. After which, the aircraft disappeared behind the hill to the northeast of the observed location, trailing flames behind it. The sound of an explosion and large plume of black smoke immediately followed." Examination of the accident site revealed that the wreckage debris was scattered throughout a neighborhood area about 1,000 ft long and 800 ft wide on a south-to-north orientation. At the far south parameter of the debris field were tail sections. The far north area contained the left engine, and left propeller and the fuselage. About 700 ft north-east from the first recovered piece of debris, the right engine and the right propeller impacted an asphalt road, and came to rest in a nearby front yard. The left wing was found about 716 ft north of the first recovered piece of debris, about 140 ft south-west of a burned house. Within the house, fragments of the outboard right wing (which also contained the fuel tank) were located. The fuselage with the attached right inboard wing, along with the left propeller and left engine were located about 310 ft downhill from the burned house on a heading of 310°. The wreckage was recovered and moved to a secure location for future examination.