NTSB Factual Report

On April 18, 2015, about 1300 eastern daylight time, a Cessna LC41-550FG, N400BZ, was substantially damaged during a fire after an emergency landing at Space Coast Regional Airport (TIX), Titusville, Florida. The private pilot, pilot-rated-passenger and an additional passenger were uninjured. Visual meteorological conditions prevailed and an instrument flight rules flight plan was filed for the cross-country flight, which departed Savannah/Hilton Head International Airport (SAV), Savannah, Georgia, about 1145 and was destined for Okeechobee County Airport (OBE), Okeechobee, Florida. The personal flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91.

According to the pilot, he planned to fly the airplane to OBE for a 50-hour service and some cosmetic maintenance work. During the preflight inspection, he noted about 7 quarts of oil in the oil sump. The pilot then departed, but approximately 1 hour into the flight and during a descent to 8,000 feet mean sea level (msl), he noticed the oil pressure decrease "into the red," while the other instruments remained "in the green." The pilot reported the loss of oil pressure to air traffic control and about 1 minute later, the oil pressure decreased to 0. He identified the nearest airport as TIX and started an emergency descent. As the airplane approached 3,000 feet msl, the engine lost all power and smoke entered the cabin through the air vents. The pilot completed a forced landing to runway 27, but after the airplane came to rest he observed flames coming from the cowling. The pilot and passengers egressed before the fire consumed most of the airplane fuselage.

Examination of the airplane by a Federal Aviation Administration (FAA) inspector revealed that the engine cowling was destroyed by fire and portions of the airframe and cabin area were substantially damaged. The inspector noted that the No. 3 cylinder exhaust valve rocker box cover was missing and three screws were missing from the No. 4 cylinder exhaust rocker box cover. A screw was also missing from the No. 4 cylinder intake valve rocker box cover, but the cover was in contact with the gasket and no gap was observed between the cover and the mounting surface. The No. 2 cylinder exhaust rocker box cover was loose; however, each of the cover's respective screws were present.

Additional examination of the airplane was conducted on-scene by representatives of the engine and airframe manufacturer, under supervision of the FAA inspector. A large amount of soot and thermal by-products were observed on the No. 3 cylinder exposed rocker arm and surrounding head surfaces. A small hole was observed on the top of the right crankcase half near the No. 5 cylinder base and a similar hole was observed on the left crankcase half near the base of the No. 4 cylinder. The through-bolt nut to the top rear crankcase section was missing and the through-bolt head had backed off from the installed position by about 1/2 inch; however, all six cylinders remained attached to the engine crankcase.

According to a representative of the Titusville Fire Department, their team performed a safety inspection for foreign object debris on runway 09/27; however, the No. 3 cylinder exhaust valve rocker box cover was not located.

The forward section of the oil sump was destroyed by fire. The oil rod was intact and displayed a small amount of dark viscous liquid on the bottom of the rod. The oil quick drain valve was in the closed position and secured to the oil sump with safety wire. Both the oil cooler and oil filter were intact and exhibited some thermal damage; the oil pressure sending unit was destroyed by fire.

A subsequent engine examination was completed at the engine manufacturer's facility under the supervision of an FAA inspector. The crankcase displayed multiple puncture holes throughout the case. Disassembly of the engine revealed that each of the six connecting rods had separated from the crankshaft at their respective journals. Multiple main oil journals were dry and heat discolored, consistent with oil starvation. The oil sump displayed thermal damage and contained metallic fragments. The main bearing journals appeared blue in color and the connecting rod journals were rusted and exhibited rotational scoring. The camshaft was broken at the No. 5/No. 6 cylinder position.

The pilot reported that he was not aware that the rocker box covers were loose and further stated that he had not removed or manipulated the covers during the time he owned the airplane. He reported that the airplane had only required 1 quart of oil in the preceding 20 hours of operation and recalled that the airplane had been "flying great."

The four-seat, low wing, fixed-gear airplane was manufactured in 2008 and powered by a Continental Motors TSIO-550-C, 310-horsepower reciprocating engine. The FAA registration records indicated that the airplane was purchased by the accident pilot in February 2015. According to the maintenance records, the airplane's most recent required service consisted of an annual inspection that was performed on June 13, 2014, at an airframe time of 459 total flight hours, 43 flight hours before the accident. At the time of the service, the engine had accumulated 459 total flight hours since its production. Additionally, a pre-buy inspection of the airplane was performed on February 6, 2015. According to the maintenance facility that performed the inspection, the engine rocker box covers were not removed during the inspection.

The engine was disassembled and inspected on October 31, 2011, following a propeller strike. The associated maintenance entry stated that the engine was disassembled, cleaned, and "all parts inspected per instructions in TCM overhaul – manual and applicable service bulletins and airworthiness directives." The engine was then reassembled with new main bearings, rod bearings, rod bolts/nuts, new seals, and gaskets. Additionally, the camshaft and lifters were replaced during this service. According to SB96-11B, a service bulletin that was issued by the engine manufacturer and active at the time of the propeller strike inspection, the engine must be completely disassembled and all rotating engine components inspected following any propeller strike. Additionally, the Continental Motors, Inc. overhaul manual stated that the engine should be disassembled completely in accordance with Chapters 12 and 13 of the manual following a propeller strike. Chapter 12 includes instructions to remove the screws, lock washers, washers, and rocker box covers to all six cylinders.

The airplane was equipped with a Garmin G1000 multi-function display that was capable of recording airplane and engine performance data to an SD data card. The data card was removed and successfully downloaded at the NTSB's Vehicle Recorder Division in Washington, D.C. The data parameters that were recorded for the accident flight included, fuel flow, exhaust gas temperature, oil pressure, and rpm.

According to the data, the airplane began a takeoff roll at 1135:35, at which point the engine rpm increased from 1,200 rpm to 2,550 rpm. The flight was uneventful until about 1249:30, when the oil pressure began a steady decline. At 1253:10, the oil pressure reached 0 psi while the airplane was at approximately 8,000 feet pressure altitude in a constant descent from 10,000 feet. In the 2 minutes and 30 seconds that followed, the exhaust gas temperature of each cylinder rose slightly and then decreased to about 400 degrees F. The airplane reached a pressure altitude of 0 feet at 12:57:00 and the indicated airspeed decreased to 0 knots approximately 30 seconds later.

NTSB Probable Cause

An inflight fire and a total loss of engine power due to oil starvation, after separation of the No. 3 cylinder exhaust valve rocker box cover for reasons that could not be determined based on the available information.