Wisconsin

The flight crew reported that while on an instrument landing system (ILS) approach with the autopilot system engaged in approach mode, they noticed that the airplane flight director indicated a climbing right turn but the airplane was still tracking the localizer and glideslope. The airplane’s ice protection was on, and no visible ice had accumulated. They reported that they disconnected the autopilot, and the airplane suddenly rolled to the right. They attempted to regain control by increasing engine power and applying counteractive control inputs, but the airplane impacted the ground in a near-wings-level attitude. Examination of the airplane’s primary flight control system and engines after the accident did not reveal any defects. The rudder trim was neutral, and the pitch trim was airplane nose up. Aileron trim could not be determined. Examination of the airplane’s autopilot components revealed deficiencies in the yaw damper system that rendered it inoperative; however, on the accident airplane the yaw damper system was an optional component and was not necessary for airplane operation. Testing of the remaining autopilot components revealed some deficiencies that could have degraded performance but would not have resulted in a complete failure of the automatic flight control system. A performance study based on ADS-B data showed that the airplane intercepted the localizer and glideslope for the ILS approach and was descending in a level attitude. While maintaining the ILS approach guidance, the airplane slowed below the 130 knots (kts) airspeed that the crew stated was the desired approach speed. The airspeed continued to slow to about 102 kts when the ADS-B data indicated that the airplane rolled slightly to the right, likely corresponding to the flight crew’s description of events after they disconnected the autopilot. The airplane continued to slow below 100 kts and the airplane was at a bank angle of 27° right wing down. Subsequently, the descent rate increased to over 4,000 ft/min and airspeed increased while ground speed remained between 80 and 90 kts. The airplane rolled sharply to the left. The sudden roll and loss of altitude after reaching a low airspeed was consistent with an aerodynamic stall. Based on the available evidence, the airplane entered an inadvertent aerodynamic stall due to exceedance of the critical angle of attack after the flight crew allowed the airspeed to decay during the instrument approach. Although an unknown anomaly in the flight director system could have resulted in the crew becoming fixated on an errant flight director indication at the expense of airspeed control, the postaccident component examination was not able to explain the errant flight director indication that the flight crew described.

The company pilot and two employees had departed on an aerial imagery survey flight of forest vegetation. The airplane began to level off at an altitude of about 16,100 ft mean sea level (msl) and accelerated to a maximum recorded groundspeed of 209 knots. Less than 2 minutes later, the groundspeed decreased to about 93 knots, and the airplane descended about 500 ft while on a steady heading. The airplane subsequently entered a rapid descent and a right turn, and “mayday, mayday, mayday” and “we’re in a spin” transmissions were broadcast to air traffic control (ATC). A witness, who was located near the accident site, noticed the airplane nose down at high rate of speed and then saw the airplane spinning rapidly about its longitudinal axis. The airplane wreckage was located in remote wetlands and wooded terrain. Postaccident examination revealed that the airplane impacted the ground in a nose-low vertical attitude and at high speed. All major components of the airplane were located at the accident site. Examination of the airframe, engines, and propellers revealed no preimpact mechanical malfunctions or failures that would have precluded normal operation. According to the aircraft performance study for this accident, when the airplane pitched down, the normal load factor decreased rapidly from about 1.6 to less than 1 G. A rapid decrease in normal load factor is consistent with a stall when the wing exceeds its critical angle of attack. At that point, the air flow becomes separated at the wing, and the wing can no longer generate the necessary lift. If the airplane is in uncoordinated flight at the stall, a spin can result. Thus, the pilot likely did not maintain adequate airspeed, causing the airplane to exceed its critical angle of attack and enter a stall and spin. An important but unknown factor before and during the initial stall was the behavior of the pilot regarding his flight control inputs, including his possible attempt to recover. The airplane’s Pilot Operating Handbook states that spins are not authorized and does not include a procedure for inadvertent spin recovery.

The pilot reported that, upon reaching the decision altitude on a GPS instrument approach, he saw the runway end identifier lights and continued the approach. Shortly after, the lights disappeared and then reappeared. He continued the approach and landing thinking the airplane was lined up with the runway by using the runway edge lights for reference. Upon touching down about 225 ft left of the runway, the airplane dug into snow and flipped over, which resulted in substantial damage to the wings and tail. The pilot reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.

The commercial pilot of the multi-engine airplane was conducting an instrument flight rules cross-country flight at night. The pilot checked in with air traffic control at a cruise altitude about 10,000 ft mean sea level (msl). About 31 minutes later, the pilot reported that he saw lightning off the airplane's left wing. The controller advised the pilot that the weather appeared to be about 35 to 40 miles away and that the airplane should be well clear of it. The pilot responded to the controller that he had onboard weather radar and agreed that they would fly clear of the weather. There were no further communications from the pilot. About 4 minutes later, radar information showed the airplane at 10,400 ft msl. About 1 minute later, radar showed the airplane in a descending right turn at 9,400 ft. Radar contact was lost shortly thereafter. The distribution of the wreckage, which was scattered in an area with about a 1/4-mile radius, was consistent with an in-flight breakup. The left horizontal stabilizer and significant portions of both left and right elevators and their respective trim tabs were not found. Of the available components for examination, no pre-impact airframe structural anomalies were found. Examination of the engines and turbochargers did not reveal any pre-impact anomalies. Examination of the propellers showed evidence of rotation at impact and no pre-impact anomalies. Review of weather information indicated that no convection or thunderstorms were coincident with or near the airplane's route of flight, and the nearest convective activity was located about 25 miles west of the accident site. Autopsy and toxicology testing revealed no evidence of pilot impairment or incapacitation. Given the lack of radar information after the airplane passed through 9,400 ft, it is likely that it entered a rapid descent during which it exceeded its design stress limitations, which resulted in the in-flight breakup; however, based on the available information, the event that precipitated the descent and loss of control could not be determined.

The airline transport pilot was landing at the destination airport after a cross-country flight in visual meteorological conditions. The tower controller stated that the airplane's landing gear appeared to be extended during final approach and that the airplane landed within the runway's touchdown zone. The tower controller stated that, although the airplane made a normal landing, he heard a squealing noise that continued longer than what he believed was typical. The pilot subsequently transmitted "go-around." The tower controller acknowledged the go-around and cleared the pilot to enter a left traffic pattern. The tower controller stated that he heard the engine speed accelerate while the airplane maintained a level attitude over the runway until it passed midfield. He then saw the airplane pitch up and enter a climbing left turn. The tower controller stated that the airplane appeared to enter an aerodynamic stall before it descended into terrain in a left-wing-down attitude. Another witness reported that he saw the airplane, with its landing gear extended, in a steep left turn before it descended rapidly into terrain. A postaccident examination did not reveal any evidence of flight control, landing gear, or engine malfunction. An examination of the runway revealed numerous propeller slash marks that began about 215 ft past the runway's touchdown zone; however, there was no evidence that any portion of the airframe had impacted the runway during the landing. Additionally, measurement of the landing gear actuators confirmed that all three landing gear were fully extended at the accident site. Therefore, the pilot likely did not adequately control the airplane's pitch during the landing, which allowed the propeller to contact the runway. Due to the propeller strikes, the propeller was likely damaged and unable to provide adequate thrust during the go-around. Further, based on the witness accounts, the pilot likely did not maintain adequate airspeed during the climbing left turn, which resulted in the airplane exceeding its critical angle of attack and experiencing an aerodynamic stall at a low altitude.

The pilot was landing at a large fly-in/airshow and following the airshow arrival procedures that were in use. While descending on the downwind leg for runway 27, the pilot was cleared by a controller to turn right onto the base leg abeam the runway numbers and to land on the green dot (located about 2,500 ft from the runway's displaced threshold). About the time the pilot turned onto the base leg, he observed an airplane taxi onto the runway and start its takeoff roll. The controller instructed the pilot to continue the approach and land on the orange dot (located about 1,000 ft from the runway's displaced threshold) instead of the green dot. The pilot reported that he considered performing a go-around but decided to continue the approach. As the pilot reduced power, the airplane entered a stall and impacted the runway in a right-wing-low, nose-down attitude. Witnesses estimated that the bank angle before impact was greater than 60 degrees. A postaccident examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation.
Analysis of a video recording of the accident showed that the airplane was about 180 ft above ground level (agl) when the turn onto the base leg began, and it descended to about 140 ft agl during the turn. The airplane's total inertial speed (the calculated vector sums of the airplane's ground speeds and vertical speeds) decreased from 98 knots (kts) to 80 kts during the turn. During the last 8 seconds of flight, the speed decreased below 70 kts, and the airplane descended from about 130 ft agl to ground impact. The wings-level stall speed of the airplane at maximum gross weight with landing gear and flaps down was 59 kts. In the same configuration at 60 degrees of bank, the stall speed was 86 kts and would have been higher at a bank angle greater than 60 degrees. Reduced runway separation standards for airplanes were in effect due to the airshow. When the accident airplane reached the runway threshold, the minimum distance required by the standards between the arriving accident airplane and the departing airplane was 1,500 ft. The video analysis indicated that it was likely that a minimum of 1,500 ft of separation was maintained during the accident sequence. Although the pilot was familiar with the procedures for flying into the airshow, the departing airplane
and the modified landing clearance during a period of typically high workload likely interfered with the pilot's ability to adequately monitor his airspeed and altitude. As a result, the airplane entered an accelerated stall when the pilot turned the airplane at a steep bank angle and a low airspeed in an attempt to make the landing spot, which resulted in the airplane exceeding its critical angle of attack. At such a low altitude, recovery from the stall was not possible. Although the airshow arrival procedures stated that pilots have the option to go around if necessary, and the pilot considered going around, he instead continued the unstable landing approach and lost control of the airplane.

The aircraft collided with a fence and a ditch when it overran runway 8R (2,272 feet by 38 feet, asphalt) while landing at the Sylvania Airport (C89), Sturtevant, Wisconsin. The commercial pilot was not injured and his passenger received minor injuries. The airplane sustained damage to its fuselage and both wings. The airplane was registered to Direct Action Aviation LLC, and was operated by Skydive Midwest. The accident flight was conducted under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Instrument meteorological conditions prevailed for the flight, which was not operated on a flight plan. The flight originated from the Jackson County Airport-Reynolds Field (JXN), Jackson, Michigan, about 1800. The pilot reported that the landing approach was normal and when the airplane crossed the runway threshold it floated and he pulled the engine power levers to the stops. He stated that although he did not remember the airplane bouncing, his passenger told him that it had. He pulled the power levers to reverse, but there was no immediate reverse thrust. He applied brakes and felt the airplane accelerate. He recognized that he would not be able to stop the airplane on the remaining runway and attempted to steer it to the north. The airplane left the runway, impacted two ditches and came to rest on a highway. The pilot stated that he should have recognized that braking action would be significantly reduced with the possibility of hydroplaning, that pulling the power levers to the stops before touchdown induced a lag in realization of reverse thrust, and that he should have executed a go-around when the airplane floated before landing. The pilot reported no mechanical failures or malfunctions of the airplane. At 1853, weather conditions reported at the Kenosha regional Airport (ENW), located 6 miles south of the accident site, included heavy rain.

During cruise flight, the pilot reported to an air traffic controller that the airplane was having engine fuel pressure problems. The controller advised the pilot of available airports for landing if necessary and asked the pilot's intentions. The pilot chose to continue the flight. GPS data recorded by an onboard avionics system indicated that the engine had momentarily lost total power about 20 seconds before the pilot reported a problem to the controller. About 7 minutes later, when the airplane was about 7,000 feet above ground level, the engine lost total power again, and power was not restored for the remainder of the flight. The pilot attempted to glide to an airport about 10 miles away, but the airplane crashed in a field about 3 miles from the airport. GPS data showed a loss of fuel pressure before each of the engine power losses and prolonged lateral g forces consistent with a side-slip flight condition. The rudder trim tab was found displaced to the left about 3/8 inch. Flight testing and recorded flight data revealed that the rudder trim tab displacement was consistent with that required to achieve no side slip during a typical climb segment. The GPS and flight data indicated that the lateral g-forces increased as the airplane leveled off and accelerated, indicating that the automatic rudder trim feature of the yaw damper system was either not engaged or not operating. The recorded data indicated autopilot system engagement, which should have automatically engaged the yaw damper system. However, the data indicated the yaw damper was not engaged; the yaw damper could have subsequently been turned off by several means not recorded by the avionics system. Testing of the manual electric rudder (yaw) trim system revealed no anomalies, indicating that the pilot would have still been able to trim the airplane using the manual system. It is likely that the pilot's failure to properly trim the airplane's rudder led to a prolonged uncoordinated flight condition. Although the fuel tank system is designed to prevent unporting of the fuel lines during momentary periods of uncoordinated flight, it is not intended to do so for extended periods of uncoordinated flight. Therefore, the fuel tank feed line likely unported during the prolonged uncoordinated flight, which resulted in the subsequent loss of fuel pressure and engine power. The propeller and propeller controls were not in the feathered position, thus the windmilling propeller would have increased the airplane's descent rate during the glide portion of the flight. The glide airspeed used by the pilot was 20 knots below the airspeed recommended by the Pilot's Operating Handbook (POH), and the reduced airspeed also would have increased the airplane's descent rate during the glide. The flight and GPS data indicated that the airplane had a gliding range of about 16 nautical miles from the altitude where the final loss of engine power occurred; however, the glide performance was dependent on several factors, including feathering the propeller and maintaining the proper airspeed, neither of which the pilot did. Although the POH did not contain maximum range glide performance data with a windmilling propeller, based on the available information, it is likely that the airplane could have glided to the alternate airport about 10 miles away if the pilot had followed the proper procedures.

The accident occurred during the Experimental Aircraft Association’s Airventure 2010 fly-in convention. Because of the high density of aircraft operations during the fly-in, the Federal Aviation Administration implemented special air traffic control procedures to accommodate traffic demand and maximize runway capacity. Arriving aircraft were issued landing instructions and clearances by a tower controller using a specified tower radio frequency. Departing aircraft were handled by another team of controllers operating on a separate radio frequency that was associated with a mobile operations unit located near the runway. Air traffic control data indicated that the accident airplane established contact with the tower controller and entered a left traffic pattern for runway 18R. As the accident airplane was turning from downwind to base leg, the controller handling departures cleared a Piper Cub for an immediate takeoff and angled departure (a procedure used by slower aircraft to clear the runway immediately after liftoff by turning across the runway edge). The accident pilot was not monitoring the departure frequency, and, therefore, he did not hear the radio transmissions indicating that the departing Piper Cub was going to offset to the left of the runway after liftoff. The accident pilot reported that, while on base leg, he became concerned that his descent path to the runway would conflict with the Piper Cub that was on takeoff roll. He stated that he overshot the runway centerline during his turn from base to final, and, when he completed the turn, his airplane was offset to the right of the runway. The pilot stated that, at this point, he decided not to land because of a perceived conflict with the departing Piper Cub that was ahead and to the left of his position. The pilot reported that he initiated a go-around, increasing engine power slightly, but not to takeoff power, as he looked for additional traffic to avoid. He estimated that he advanced the throttle levers "probably a third of the way to the stop," and, as he looked for traffic, the stall warning stick-shaker and stick-pusher systems activated almost simultaneously as the right wing stalled. The airplane subsequently collided with terrain in a nose down, right wing low attitude. A postaccident review of available air traffic control communications, amateur video of the accident sequence, controller and witness statements, and position data recovered from the accident airplane indicated that the Piper Cub was already airborne, had turned left, and was clear of runway 18R when the accident airplane turned from base to final. The postaccident examination did not reveal any preimpact mechanical malfunctions or failures that would have precluded normal operation of the airplane. The airplane flight manual states that, in the event of a go-around, the pilot should first advance engine thrust to takeoff power and then establish Vref (reference landing approach speed). The pilot's decision not to select takeoff power during the go-around directly contributed to the development of the aerodynamic stall at a low altitude.

The on-demand cargo flight departed for the destination airport and was delayed en route due to repetitive destination airport closures. The closures were the result of snow-contaminated runways. The pilot then diverted to an alternate airport due to concerns about remaining fuel reserves. The airplane experienced a loss of engine power during an instrument approach at the alternate airport and impacted the ground about 200 yards short of the landing runway. A postaccident inspection of the airplane revealed no usable fuel on board.