WPR17FA066

The pilot's failure to maintain airplane control upon entering instrument meteorological conditions, which resulted in the airplane exceeding its critical angle of attack and an aerodynamic stall. Contributing to the accident was the pilot's personal pressure to complete the flight despite the weather conditions.

The airline transport pilot and four passengers planned to make a 300-nautical-mile cross-country flight in the airplane to return home. They arrived at the airport about noon and loaded their bags into the airplane. The pilot made an unsuccessful attempt to start the engines, and the occupants deplaned and waited for some time. During a second attempt to begin the flight, a ground controller informed the pilot that he was required to file an instrument flight rules (IFR) flight plan before departure. After the occupants deplaned a second time, they went to the airport terminal where the pilot asked a flight school employee to provide instructions for filing an IFR flight plan. According to the flight school employee, the pilot appeared rushed, and the passengers were anxious to complete the flight. According to the surviving passenger, after one of the other passengers started to make ground transportation arrangements, the pilot's wife insisted they would fly the passengers home. The pilot filed an IFR flight plan, and the pilot and passengers boarded the airplane for the third time. At the time of the accident, IFR conditions prevailed at the departure airport with a visibility of 2 miles in light precipitation and mist, scattered clouds at 600 ft above ground level (agl) and an overcast ceiling at 4,200 ft agl. It could not be determined when the pilot had last flown in instrument meteorological conditions or when he had last completed an instrument competency check. However, it is likely that the pilot was not instrument current as he was unfamiliar with basic instrument flight planning procedures and had to be coached through the readback of his IFR clearance. The airplane departed normally and entered a climb. Seconds later, the airplane entered a cloud and began a turn, at which time it began to shake violently as the stall warning horn sounded, consistent with an aerodynamic stall. The airplane descended from about 900 ft above ground level and impacted multiple residences about 1 nautical mile from the departure airport. Examination of the airframe and engines revealed no evidence of any preimpact mechanical malfunctions that would have precluded normal operation. The blades of both propellers displayed rotational damage signatures that were consistent with the engines producing power at impact. Toxicology results indicated that the pilot was not impaired by carbon monoxide or drugs. Although the pilot's autopsy showed that he had coronary artery disease and was at increased risk of incapacitation from a cardiac event, the surviving passenger reported that the pilot was manipulating the controls during the descent to impact. Therefore, pilot impairment or incapacitation likely did not contribute to the accident. The pilot's decision to complete the flight despite the IFR weather conditions was likely driven by his own self-induced pressure, influenced by the passengers' need to return home and his wife's insistence that the departure would proceed as originally planned.    Calculations indicated that the airplane was loaded over its maximum gross takeoff weight by about 300 pounds. Additionally, the airplane's center of gravity (CG) was forward of the forward limit for its maximum gross weight. Although CGs that are forward but within the approved envelope generally result in more favorable stall characteristics, the airplane was loaded outside of published limits, and its performance under these conditions was unpredictable.

The Sheriff-Coroner of the County of Riverside, Perris, California, conducted an autopsy on the pilot. The cause of death was listed as "multiple blunt impact injuries." The autopsy described an enlarged heart with 70% narrowing of the left anterior descending and right coronary arteries and 40% narrowing of the left circumflex artery. A blood sample taken by the coroner's office detected no drugs of abuse, alcohol, or carbon monoxide. The FAA's Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed toxicology testing on specimens from the pilot, the front right seat passenger, and another passenger. The testing did not identify any drugs or ethanol in the samples that were provided for the pilot's toxicology, and the specimen provided was not sufficient for carbon monoxide analysis. The right front seat passenger's toxicology did not detect carbon monoxide. The other passenger's toxicology detected 21% carbon monoxide; the reason for the passenger's high carbon monoxide level is unknown. In the hours before the accident, IFR conditions prevailed at RAL due to low visibilities and ceilings. A review of the RAL weather observations indicated that rain began at 1152 and continued through 1653, with very light precipitation and mist about the time of the accident. Review of weather radar imagery showed that a small area of precipitation associated with very light intensity echoes was present at 1640 immediately north of the accident site. The 1600 recorded weather observation at RAL included wind calm, visibility 2 miles in light rain and mist, ceiling overcast at 700 ft agl, temperature and dew point 11°C, and an altimeter setting of 29.83 inches of mercury. The 1637 recorded weather observation at RAL included wind calm, visibility 2 miles in light rain and mist, scattered clouds at 600 ft agl, overcast ceiling at 4,200 ft agl, temperature and dew point 11°C, and an altimeter setting of 29.82 inches of mercury. A terminal aerodrome weather forecast for Ontario International Airport (ONT), Ontario, California, located about 10 nm southeast of RAL, was issued at 1302 and was valid for a 27-hour period beginning at 1300. The forecast valid for the time of the accident expected marginal VFR conditions to prevail with light and variable winds at 4 knots or less, visibility of 5 miles in light rain showers and mist, with scattered clouds at 1,500 ft agl, and a ceiling broken at 2,500 ft. The next scheduled forecast for ONT was issued at 1537 and continued to expect marginal VFR conditions to prevail with light and variable winds, visibility 3 miles in light rain and mist, with a ceiling overcast at 1,000 ft agl. Records obtained from a private industry flight service station indicated that when the pilot filed his IFR flight plan, he was in possession of adverse weather information indicating that he had already acquired the information through personal means. The pilot's personal weather source was not determined. The 83-year-old pilot held an airline transport pilot certificate with a rating for airplane single-engine land and commercial privileges for airplane multi-engine land. He also held a flight instructor certificate with ratings for airplane single-engine land, airplane multi-engine land, and instrument airplane. The pilot's most recent second-class medical certificate was issued on October 13, 2016, and included the restriction that he must wear corrective lenses. At the time of the exam, the pilot reported that he had accumulated 9,600 hours of flight experience of which 21 hours were in the previous 6 months. An excerpt of the pilot's personal flight record, which covered 2008, was furnished by the family. His most recent flight logbooks were not recovered. It could not be determined when the pilot had last flown in instrument meteorological conditions or when he had last completed an instrument competency check. According to Federal Aviation Administration (FAA) records, the airplane was manufactured in 1974 and registered to the pilot and his wife on September 25, 2007. The airplane was powered by two Continental TSIO-520 J, turbocharged, direct-drive, air-cooled, 310-horsepower engines. A review of the airplane's maintenance logbooks revealed that the most recent annual inspection was completed on February 1, 2017, at an accumulated flight time of 4,830 hours. At the time of annual inspection, both the left and right engines had accrued about 1,265.1 flight hours since their most recent overhauls. The airplane was equipped with two main wing fuel tanks with a total capacity of 102 gallons and two auxiliary wingtip tanks with a total capacity of 63 gallons. According to a fuel station attendant who worked for the fixed base operator at RAL, on February 25, 2017, he fueled the airplane at the pilot's request. The attendant topped off each of the airplane's four fuel tanks adding a total of 54 gallons of 100LL aviation gasoline. A fuel sample taken by an FAA inspector from the fuel truck that was used to refuel the airplane did not show any evidence of water or debris contamination. Weight and Balance An airplane weight and balance estimate was computed using occupant weights from the autopsy reports and from the surviving passenger. The baggage weight was determined by weighing an assortment of personal effects and baggage recovered from the accident site. The computed total weight was 5,812 pounds (lbs), which was 312 lbs over the airplane's maximum allowable gross weight of 5,500 lbs. The manufacturer does not provide center of gravity (CG) limits for weights above gross weight; the computed CG of 36.82 inches was forward of the forward limit of 38.67 inches at gross weight. Figure 1 shows the airplane weight and balance estimate plotted on the manufacturer's published CG moment envelope diagram from the pilot's operating handbook (POH). Figure 1 - Airplane Center of Gravity Moment Envelope Plotted with Main & Auxiliary Tanks at Full Capacity According to the FAA Airplane Flying Handbook (FAA-H-8083-3B), the flight characteristics of a multi-engine airplane will vary significantly with shifts of the CG within the approved envelope. At forward CGs within the envelope, the airplane will be more stable, with a slightly higher stalling speed, a slightly lower cruising speed, and favorable stall characteristics. However, the airplane's performance outside the performance envelope cannot be predicted. Stall Characteristics According to the POH, the airplane's stall speed was 75 knots with no bank and 78 knots with 20° of bank. Fuel Consumption Climb and endurance performance computations performed using the airplane POH indicated that the airplane would have burned about 12 gallons of fuel during a climb to 12,000 ft, which was the pilot's filed cruising altitude, and contained enough fuel to fly about 790 nautical miles (nm) at the pilot's reported cruise airspeed of 160 kts. The distance from RAL to SJC was about 300 nm. The accident site was located in a residential area about 1 nm northeast of RAL at an elevation of about 800 ft. The initial impact point (IIP) was identified by a broken chimney and a section of airframe located on the roof of house No. 1 (H-1 in the wreckage diagram located in the NTSB public docket). Multiple airplane fragments were found along the debris path, which was oriented on a heading of about 345° magnetic. House No. 2 (H-2) was located about 50 ft from the IIP and was consumed by postcrash fire. The airplane's main wreckage was found in a bedroom on the southwest end of house No. 3 (H-3) about 100 ft from the IIP. The main wreckage was comprised of the cabin, both engines, portions of the left and right wings, and the left propeller, which was underneath the main wreckage, which was consumed by postcrash fire. The aileron flight controls were traced from the control column to the right-wing bell crank, where the cables had separate