ERA18FA206

The pilot's exceedance of the airplane's critical angle of attack while maneuvering to land, which resulted in an aerodynamic stall.

The private pilot of the multiengine airplane was in cruise flight at 23,000 ft mean sea level (msl) in day visual meteorological conditions when he reported to air traffic control that the airplane was losing altitude due to a loss of engine power. The controller provided vectors to a nearby airport; about 7 minutes later, the pilot reported the airport in sight and stated that he would enter a downwind leg for runway 14. By this time, the airplane had descended to about 3,200 ft above ground level. Radar data indicated that the airplane proceeded toward the runway but that it was about 400 ft above ground level on short final. The airplane flew directly over the airport at a low altitude before entering a left turn to a close downwind for runway 21. Witnesses stated that the airplane's propellers were turning, but they could not estimate engine power. When the airplane reached the approach end of runway 21, it entered a steep left turn and was flying slowly before the left wing suddenly "stalled" and the airplane pitched nose-down toward the ground. Postaccident examination of the airplane and engines revealed no mechanical deficiencies that would have precluded normal operation at the time of impact. Examination of both propeller systems indicated power symmetry at the time of impact, with damage to both assemblies consistent with low or idle engine power. The onboard engine monitor recorded battery voltage, engine exhaust gas temperature, and cylinder head temperature for both engines. A review of the recorded data revealed that about 14 minutes before the accident, there was a jump followed by a decrease in exhaust gas temperature (EGT) and cylinder head temperature (CHT) for both engines. The temperatures decreased for about 9 minutes, during which time the right engine EGT data spiked twice. Both engines' EGT and CHT values then returned to normal, consistent with both engines producing power, for the remaining 5 minutes of data. It is possible that a fuel interruption may have caused the momentary increase in both engines' EGT and CHT values and prompted the pilot to report the engine power loss; however, the engine monitor did not record fuel pressure or fuel flow, and examination of the airplane's fuel system and engines did not reveal any mechanical anomalies. Therefore, the reason for the reported loss of engine power could not be determined. It is likely that the pilot's initial approach for landing was too high, and he attempted to circle over the airport to lose altitude. While doing so, he exceeded the airplane's critical angle of attack while in a left turn and the airplane entered an aerodynamic stall at an altitude too low for recovery.

The pilot held a Canadian private pilot certificate for single- and multi-engine land airplane and instrument airplane. A review of the pilot's logbook revealed that, as of July 27, 2018, he had a total of 590.3 hours of flight experience, of which 155.2 hours were in multi-engine airplanes. The pilot logged about 136 hours total in the accident airplane and about 82.6 of those hours were as pilot-in-command. In the 90 days before the accident, the pilot logged a total of 29.2 flight hours, with 13.4 hours in the previous 30 days; all of which was in the accident airplane. The pilot held a Transport Canada Category 3 medical certificate, which was issued on September 13, 2017, with no limitations. An autopsy of the pilot was conducted by the Office of Chief Medical Examiner, Augusta, Maine, on July 31, 2018. The cause of death was determined to be "extensive blunt force trauma." Toxicological testing performed by the FAA's Forensic Sciences Laboratory was negative for ethanol and drugs. The airplane was manufactured in 1982 and was equipped with two six-cylinder Lycoming TIO-540-U2A engines each rated at 350 horsepower at 2,500 rpm. The airplane's engines and propellers had been modified with a Machen conversion under supplemental type certificate (STC) SA1658NM. A review of the airplane's Journey Log revealed that the last annual inspection was performed on May 9, 2018, at an airframe total time since new of 4,856.1 hours. The airplane had accrued 21.1 hours since the annual inspection. The left engine had 196.8 hours total time since overhaul (TTSO) and the right engine had 169 hours TTSO. The left and right propellers each had 92.2 hours TTSO. The last logged entry in the Journey Log was on July 27, 2018, 3 days before the accident. On July 30, 2018, about 1044 eastern daylight time (EDT), a Piper PA-60-602P, Canadian registration C-GRRS, was destroyed when it impacted terrain while attempting to land at Greenville Airport (3B1), Greenville, Maine. The foreign-certificated pilot and two passengers were fatally injured. The airplane was registered to and operated by the pilot under Canadian Aviation Regulations as a recreational flight. Visual meteorological conditions prevailed at 3B1 at the time of the accident, and an instrument flight rules flight plan was filed for the flight, which departed Pembroke Airport (CYTA), Pembroke, Ontario, Canada, about 0905, and was destined for Charlottetown Airport (CYYG), Prince Edward Island (PEI), Canada. According to the CYTA airport manager, the pilot had been a regular customer at the airport for several years. The pilot flew the accident airplane into CYTA 3 days before the accident and purchased 117 gallons of 100LL fuel. The airport manager, who personally fueled the airplane that day, said that he topped off the wing tanks first, followed by the center tank. He did not fuel the auxiliary tank. The manager said that each of the fuel caps felt tight and he made sure they were properly fitted back onto each tank. The airplane was then placed in a hangar until the morning of the accident. A review of air traffic control communications revealed that, after departure, the airplane climbed and leveled off at 23,000 ft mean sea level (msl) and the pilot contacted the Boston Air Route Traffic Control Center at 1019:39. About 13 minutes later, the pilot told the controller, "...we're losing altitude trying to figure out what's going on." The controller then began to vector the airplane toward 3B1, which was about 17 miles southeast. At 1033, the controller asked the pilot, "...are you producing power right now or have you lost power." The pilot responded, "I think I've lost power..." The controller asked the pilot if he could make Greenville Airport, and the pilot responded, "Ah I think so." The controller continued to vector the pilot to 3B1 and declared an emergency on his behalf. At 1040:41, the pilot reported that he had the airport in sight and was going to join the downwind leg of the traffic pattern for runway 14. Radar data indicated that the airplane was at an altitude of about 4,600 ft msl at this time. The airplane continued to descend as it turned onto the base and final legs of the traffic pattern for runway 14. At 1043:32, said the pilot transmitted, without a call sign, "I gotta turn around and ahh we're a little high obviously." About this time, the airplane was on a short final for runway 14 at an altitude of about 1,800 ft msl (about 400 ft above ground level). The airplane then entered a left turn to the northwest and was over the airport when radar contact was lost at 1043:48. A witness was standing on the airport's apron near the terminal building between runway 14 and 21 when he first saw the airplane approaching the airport from the south. The witness said the airplane was "low." It flew over the center of the airport and made what appeared to be a left downwind entry for runway 21. There was no smoke trailing the airplane and the landing gear was retracted. The witness said both propellers were turning, but he could not tell how fast they were turning or if one was turning faster than the other. He was standing next to active construction equipment at the time, which prevented him from fully hearing the engines. When the airplane reached the approach end of runway 21, it began a "shallow" left turn. The nose of the airplane was "high" and the airplane was "going so slow." He said, "It was like it almost stopped in the air" before the left wing suddenly dropped and the airplane dove toward the ground and disappeared behind an embankment. The witness saw a debris cloud and knew that the airplane had crashed. A second witness, who was a commercial pilot, was standing in front of a hangar on the southeast side of runway 3/21 when he saw the airplane approaching the airport from the west. Instead of landing on runway 14, the airplane continued to fly over the center of the airport. The witness said that the airplane flew directly over him as it made a left turn and flew parallel to runway 3/21. He stated that both propellers were turning, and the engines were producing power; however, he could not estimate an engine speed. He said the airplane was not gliding because it maintained its altitude. The witness could not recall if the landing gear or flaps were extended but recalled that the belly of the airplane was painted black. When the airplane approached the end of the runway, it began a "shallow" left turn and was flying "really slow." The bank angle continued to increase to a point where he could see the entire top of the airplane. The airplane then pitched up and appeared to momentarily "stop" before the left wing "stalled" and the nose pitched down toward the ground. The witness did not hear any increase in engine noise before the impact. He also said that he did not believe the pilot was trying to land on runway 21 because he was positioned "way too close" to the runway. The airplane came to rest in field about 100 yards from the approach end of runway 21 on a magnetic heading of 220°. All major components of the airframe were accounted for at the site and there was no post-impact fire. The wreckage was contained to where it impacted the ground. The nose and forward fuselage area were compressed aft from impact; both engines were partially buried in the ground, and the empennage was compressed and twisted to the left. The tail section appeared undamaged and was twisted to the left. Both wings remained attached to the airframe at the wing root and sustained impact damage. Both wing fuel tanks were breached, but the fuel finger screens in both tanks were absent of debris. The center fuel tank (bladder-type) was breached, and the auxiliary fuel tank remained in the airplane but was breached. According to first responders, about 20 gallons of fuel was recovered from the site. The vegetation forward of the wreckage displayed fuel blighting. The fuel selector hand