Greenville, ME, USA
C-GRRS
Piper PA60
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.
HISTORY OF FLIGHTOn 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. PERSONNEL INFORMATIONThe 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. AIRCRAFT INFORMATIONThe 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. METEOROLOGICAL INFORMATIONThe 1056 weather conditions reported at 3B1 included wind from 310° at 8 knots variable between 260° and 360°, clear skies, temperature 23°C, dew point 14°C, and an altimeter setting of 30.09 inHg. AIRPORT INFORMATIONThe 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. WRECKAGE AND IMPACT INFORMATIONThe 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 handles were impact damaged and their position could not be determined. Continuity of the fuel system from the wings to the center fuel tank was established. The center sump was filled with 100LL fuel and the screen was absent of debris. The Nos. 1 and 4 fuel shutoff valves were in the "Open" position, and the Nos. 2 and 3 cross-feed valves were in the "Closed" position. The left and right fuel boost pumps were located and the main fuel line to each pump was separated from impact. Fuel was observed draining from each pump. Each pump was tested on a 24-volt battery and both pumps were functional. The left and right main fuel tank filters were removed and disassembled. Both were absent of debris. The flight controls were heavily fractured, but control continuity was established for the elevator and rudder to mid-fuselage. Both flight control wheels were broken off from impact; but the control column and linkages for the control yoke and rudder pedals were observed in the cockpit area. Both left and right seat rudder pedals, and the outboard rudder pedal for the right seat remained attached to their respective linkages. The right seat inboard rudder pedal had separated. Continuity to mid-cabin was established for the left- and right-wing flaps and ailerons. The left flap actuator appeared fully extended, and the right flap actuator was near the fully-retracted position. The rudder trim was neutral, and the elevator trim was consistent with one-quarter nose-up trim. The landing gear selector handle in the cockpit was impact damaged but appeared to be in the retracted position. The left main gear remained attached to the left wing and the right main gear had separated. The nose wheel was under the fuselage and the tire had separated. The cockpit area sustained extensive impact damage, with more of the damage occurring to the left (pilot) side area. The throttle levers were positioned between mid- and full power and bent to the left. Both propeller levels were full forward. Both mixture control handles were full forward and bent to the right. The flap selector handle was in the fully extended position. The left engine remained attached to the airframe by the engine mount and sustained moderate impact damage. Visual examination of the engine revealed no obvious evidence of pre-impact mechanical malfunction or fire. The propeller was removed to facilitate the examination. The top spark plugs and the vacuum pump were removed, and the crankshaft was rotated by hand via the vacuum pump drive spline. The crankshaft rotated freely, and compression and valve train continuity were established to each cylinder and to the accessory section. The combustion chamber of each cylinder was examined through the spark plug holes utilizing a lighted borescope; no anomalies were observed. The bottom spark plugs were removed and examined along with the top spark plugs. Each plug, except the No.2 top plug, which was oil-soaked, was gray in color consistent with normal wear as per the Champion Check-a-Plug chart. The propeller governor was partially displaced from the mounting pad due to impact. The pitch control rod remained securely attached at the control arm and the drive rotated freely. The gasket screen was absent of contamination. The left and right magnetos, along with their respective ignition harnesses (which were impact damaged), remained attached to the engine. The magneto-to-engine timing check found both magnetos beyond manufacturers limits; however, the magneto flanges (under each clamp) were displaced during impact. The magnetos and their damaged harnesses were removed and produced spark at each distributor tower when manually rotated. All engine compartment fuel lines were found in place and secure at their respective fittings. Fuel was found during the removal of various fuel system components. The fuel injection servo remained securely attached at the mounting pad of the plenum. The throttle/mixture controls were found securely attached at their respective control arm of the servo. The serrated engagement at each control arm was securely mated and secured by the locking nut. The plug on the side of the injector body was secure with the safety wire in place. The servo fuel inlet screen was free of contamination. The fuel injection servo and induction system were examined and observed to be free of obstruction. The Shadin fuel flow transducer was examined. The transducer fuel lines remained attached at the inlet and outlet. The transducer was observed to flow when air was applied, and the vane could be heard spinning. The fuel injection servo was disassembled. The ball/stem valve and internal diaphragms remained intact. There were no visible contaminants within the fuel cavities and passages of the servo. The fuel flow divider remained secure at the mounting bracket situated at the top of the engine. The fuel lines remained secure at each flow divider fitting and fuel injector at each cylinder. The flow divider was disassembled. Fuel was found within the flow divider. There was no evidence of internal mechanical malfunction or obstruction to fuel flow. The diaphragm was intact and undamaged. The fuel injection nozzles remained secure at each cylinder with the respective fuel line attached. The nozzles were removed and examined. The nozzles remained free of visible contamination or obstruction to flow. The fuel pump was securely attached to the engine at the mounting pad. The fuel lines remained secure at their respective fittings. The fuel pump was removed for examination. The drive remained intact and rotated without binding. The starter was securely attached at the mounting pad, with the electrical connection secure at the post. The alternator was separated from the engine and destroyed. The vacuum pump was disassembled, and the rotor/vane assembly was intact and undamaged. The oil filter and suction screen were removed from the engine and disassembled. The oil filter and screen were absent of debris. The turbocharger system components remained secure at their respective mountings. The turbocharger compressor and turbine impellers remained intact and undamaged. There was no evidence of foreign object ingestion. The turbine impeller was free to hand rotate. Each exhaust system clamp and pipe were secure at each cylinder location. The tail pipe remained secure at the turbocharger flange. The exhaust bypass valve (wastegate) remained secure at each turbocharger. The wastegate linkage and cross bar remained intact and secure. The wastegate butterfly valve remained intact and undamaged. The turbocharger and exhaust system components exhibited gas path coloration consistent with normal operation and were free of oil residue. The turbo system control (oil pressure) and pressure sensing (manifold) lines remained secure at their respective components throughout the turbocharger system. The compressor inlet and discharge scat tubes remained securely clamped at each turbocharger and airbox. The alternate air doors remained in the closed/off positions on each side of the induction system. The induction system remained free of visible obstruction to flow. The manifold pressure relief valve remained intact and securely attached to the firewall mounted airbox. The valve seat remained undamaged and seated. The mesh air filter within the airbox remained intact and free of visible contaminates. The automatic alternate air door remained intact and functioning. The sonic nozzle and attach
The pilot's exceedance of the airplane's critical angle of attack while maneuvering to land, which resulted in an aerodynamic stall.
Source: NTSB Aviation Accident Database
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