ERA17FA117

The pilot's failure to properly secure oil and fuel line fittings during maintenance, which resulted in an inflight engine fire, and his subsequent loss of control while maneuvering for landing. Contributing to the accident was the pilot's diverted attention due to the inflight fire.

The sport pilot, who was the owner and builder of the experimental, amateur-built airplane, had not flown the airplane in over 4 months due to a fuel leak. Two days before the accident, he reported that he had corrected the leak by repairing a fuel outlet connection near the fuel shutoff valve in the cockpit. The pilot departed and remained in the airport traffic pattern with the intent of performing touch-and-go takeoffs and landings. During final approach for the first landing, several witnesses observed the airplane on fire before it suddenly entered a nose-down descent and impacted a residence. Examination of the wreckage revealed evidence of an inflight fire in the engine compartment; the bottom oil line where it attached to the oil filter by a blue aluminum nut was not secure. In addition, the fuel regulator fuel intake line at the regulator attach point had little torque and spun freely on the threads. Both connections were inside the engine compartment and shared no commonality with the pilots previously reported fuel leak at the outlet connection in the cockpit. It is likely that, while performing engine maintenance, the pilot failed to properly torque the oil and fuel regulator fittings. Normal engine vibrations during the flight likely resulted in one of the fittings becoming loose and introducing flammable liquid into the engine compartment. Upon contact with hot engine components, the fluid ignited and resulted in an engine compartment fire. Because both the oil and fuel systems were compromised by loose connections, whether the fire was caused by fuel or oil could not be determined. Although an autopsy of the pilot identified severe coronary artery disease, which would have placed him at high risk for an acute cardiovascular event, it is unlikely that symptoms from his heart disease contributed to his inability to manage the inflight emergency. The rapidly developing emergency caused by fire and smoke, distracted the pilot who had little recent experience in the airplane. The pilot's diverted attention likely resulted in his failure to recognized that the airplane was going to exceed its critical angle of attack and enter an aerodynamic stall.

The Commonwealth of Massachusetts Office of the Chief Medical Examiner, Boston, Massachusetts, performed an autopsy of the pilot. The cause of death was multiple blunt force and thermal injuries. Severe coronary artery disease with a previously placed stent was found in the left anterior descending coronary artery. In the area of the stent, there was 90% stenosis, and in the more distal portion of the artery, there was 80% stenosis. In the circumflex artery, there was 80% stenosis in the area of a previous stent and 40% focal narrowing elsewhere. The right coronary artery had up to 40% stenosis from atherosclerosis. There was no gross evidence of a previous heart attack, but microscopy demonstrated interstitial fibrosis, hypertrophic cardiomyocytes, and hypertensive changes of the vasculature. The FAA's Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed toxicology testing on specimens of the pilot. Testing identified rosuvastatin in blood and urine. Rosuvastatin is a cholesterol lowering medication often marketed with the name Crestor and is not considered impairing. The 1254 automated weather observation at LWM included variable wind at 4 knots, 10 miles visibility, scattered clouds at 9,000 ft, temperature 13°C, dew point -2°C, and an altimeter setting of 30.35 inches of mercury. According to Federal Aviation Administration (FAA) airman records, the pilot received his sport pilot certificate on May 21, 2014. Review of his logbook revealed 128.5 total hours of flight experience and 28 hours in the accident airplane make model as of his last logged flight about four months before the accident. The pilot did not hold an FAA medical certificate, nor was he required to as a sport pilot. The pilot/owner purchased the airplane in January 2015 from the manufacturer in kit form. The pilot/owner completed the build and it was issued a special airworthiness certificate for experimental airplane on May 4, 2016. It was a two-seat, single-engine, low-wing, tailwheel-equipped airplane that was equipped with a Jabiru 3300L six cylinder, 120-horsepower reciprocating engine. Airframe maintenance records indicated that the airplane had accumulated 28.4 hours total time as of the last recorded entry on October 8, 2016; on this day, the pilot flew 1.4 hours. The engine logbook had one entry dated May 1, 2016 that reported, "ground run no leaks." No additional engine maintenance was documented. All components of the airplane were accounted for at the accident site and there was evidence of both pre- and postimpact fire. The airplane struck the roof of a three-story condominium building located about 1,800 ft from the approach end of runway 14. The airplane was found in the attic and upper bedrooms in a nose-low attitude on a heading about 208°. The empennage partially protruded from the roof. Both wings remained attached to the fuselage at their respective wing roots and were bent aft about 45°. The bedroom where the airplane came to rest caught fire, but was quickly extinguished by the building's fire suppression system. Fire damage was limited to the rooms in the immediate vicinity of the airplane. The engine separated from the firewall and came to rest upright against a wall about 5 ft forward of the fuselage. The engine exhibited fire damage on the left side. The two-blade fixed P-Tip propeller blades separated about 12 inches from the propeller hub. The 17-gallon polymer fuel tank remained intact and secured behind the firewall and directly forward of the instrument panel. It contained about 7 gallons of 100 low lead aviation fuel. Fuel lines leading from the fuel tank were severed during impact and were leaking when the fire department arrived on scene. The fuel shutoff valve, which was installed at the lower side of the tank above the pilot's feet, was separated and found loose in the wreckage and was heavily fire damaged; its preimpact position could not be determined. The aluminum plumbing between the valve and the gascolator was consumed by fire; however, the fittings remained intact. The firewall-mounted gascolator contained residual fuel that resembled 100 low lead aviation fuel. The filter contained no contaminants and was not damaged. The throttle body separated from the engine but remained attached by the control cable and was slightly damaged by impact forces. It displayed exterior discoloration and sooting, but no evidence of internal damage. The fuel regulator component remained attached to the throttle body; however, the fuel line into the regulator from the fuel supply had no torque and was easily spun by hand where it was threaded into the regulator. The throttle body was opened and displayed some discoloration that appeared like soot inside the air intake. The fuel regulator showed some soot deposits. Both intake and outflow lines and their respective connection nuts and couplers were undamaged at the unit and did not show any signs of heat damage, but areas under and to the left of the unit showed evidence of fire. The spark plugs were removed; the electrodes exhibited normal wear and color when compared to a Champion inspection chart. Examination of the magnetos revealed no anomalies. The engine crankshaft was turned manually; internal engine continuity was confirmed. Compression and suction were observed on all cylinders and valve action was correct. Flight control continuity was confirmed by operating the push/pull rods to their respective locations on each flight control surface. All connections remained intact. The aileron connections were traced visually to the dual stick flight controls but could not be operated due to impact damage. Rudder control continuity was visually confirmed, but the controls could not be operated due to impact damage. The engine sustained fire and heat damage, with the heaviest concentration of heat damage to the lower left side of the engine. Thermal damage propagated aft past the intake and exhaust manifolds through the rear of the engine. The oil filter was fused to the engine and could not be removed. The lower oil line that connected to the oil filter was not secured. The blue aluminum connection nut was loose. There was oil spray on the lower left side of the engine. The leading edge of the intact manifold expansion gaskets were heavily damaged by fire. All intake and exhaust manifolds on the left side of the engine showed evidence of external heat signatures. There was no evidence of heat damage to the right side of the engine. The engine cowl showed interior heat damage to the bottom side with the heaviest concentrations on the bottom left and aft. Soot, discoloration, and heat signatures were on the bottom of the fuselage and on the leading edge of the radio antennae, which exhibited blistering. Soot was also on the inboard portion of the right wing, and a soot pattern was along the right side of the fuselage that originated from an area near the front of the airplane and extended out under the right wing toward the tail. The instrument panel was impact- and heat-damaged. It contained an Xtreme-EFIS that can display primary flight display information, navigation information, and, optionally, engine information. The unit could not be separated from the instrument panel in the field, so the entire instrument panel was removed from the wreckage and sent to the NTSB Vehicle Recorder Division for additional examination and download. The SD card was successfully read using the manufacturer's software. Only one file, from February 5, 2016, was recovered, and this file was consistent with ground-only operation. No data pertinent to the investigation was recovered. On February 28, 2017, about 1302 eastern standard time, an experimental, amateur-built Sonex, N315AL, was substantially damaged when it collided with a building in Methuen, Massachusetts, during final approach for landing at Lawrence Municipal Airport (LWM), Lawrence, Massachusetts. The sport