Cessna 208B Grand Caravan

The pilot and three other crew members were performing flight testing for a new Supplemental Type Certificate (STC) for the single-engine turboprop-powered airplane. After departure, the pilot performed several maneuvers from the test card, then configured the airplane with the flaps extended for an intentional accelerated stall in a 30° left bank with the engine torque set to 930 ft-lb. Analysis of ADS-B data combined with a simulation matching the recorded trajectory of the accident maneuver revealed that, after the stall, the airplane rapidly rolled to the left, reaching a roll angle of 120° while the pitch angle decreased to 60° nose down. The airspeed rapidly increased, exceeding both the maximum flaps-extended speed (Vfe) and the airplane’s maximum operating speed (Vmo). Recorded engine data indicated that, after the stall, the engine torque increased. ADS-B data was lost at an altitude about 7,000 ft above ground level; the final track data indicated an approximate 8,700 ft/min rate of descent. Witnesses observed the airplane break up in flight and subsequently spiral to the ground. The wreckage was found in a rural field distributed over a distance of about 1,800 ft. Analysis of the aerodynamic loads in an overspeed condition showed that the wing design stress limit loads would be exceeded at high speeds with full flaps. The simulation of the stall maneuver indicated that reducing engine power to idle after the nose dropped could have reduced the rate at which the airspeed and associated aerodynamic loads increased, and would have likely given the pilot more time to recover. The airplane was equipped with an Electronic Stability and Protection (ESP) system, which was designed to deter attitude and airspeed exceedances during hand-flying and maintain stable flight by applying an opposite force to the direction of predetermined travel. It was designed to provide a light force that can be overcome by the pilot. To deactivate the ESP, the pilot needed to navigate to a specific page in the primary function display (PFD). Although the accident pilot was an experienced test pilot and qualified to operate the airplane, his experience with the accident airplane’s avionics system could not be determined. Videos of his previous flights in the airplane suggested that he was unfamiliar with the ESP system, as he did not deactivate it before the flight nor discuss the forces it was applying during the flight. Onboard video recording from a test flight the day before the accident indicated that, while performing a turning stall at idle power and 30° of left bank with the wing flaps extended, the airplane rapidly entered a left roll to a maximum of 83° before the pilot recovered to a wingslevel attitude. After recovery, the pilot pitched the airplane’s nose down about 25° in order to “get some airspeed back,” during which the ESP activated the autopilot to effect recovery to a level attitude. The airplane continued to gain airspeed, exceeding the Vmo of 175 knots and reaching 183 knots indicated airspeed, before pilot arrested the airplane’s acceleration and disconnected the autopilot. These two exceedances illustrated shortcomings in the test execution. First, although the 83° roll exceeded the allowable roll limit during this maneuver, the crew failed to identify this exceedance even though they discussed what angle had been reached and had a data acquisition system on board, which they could have consulted to determine the maximum roll angle reached during the maneuver. Correctly identifying the roll exceedance would have resulted in a “failed” test. In accordance with risk mitigation procedures for the test plan, the test buildup should have been stopped after roll limits were exceeded in order to determine the reasons for the exceedance and to implement corrective actions before proceeding with higher-risk conditions in the test plan. Secondly, after exceeding Vmo, the crew did not remark upon the exceedance, and even though the exceedance met the requirements for an overspeed inspection as described in the airplane’s maintenance manual, there was no indication that this inspection was completed. The accident flight simulation indicated that, during the stall immediately preceding the accident, it is likely that the ESP activated as the airplane pitched in excess of 19° nose-up. This would have required the pilot to apply more aft force on the control column in order to induce the stall. After the stall, the ESP would have activated at 45° bank, then deactivated as the airplane quickly exceeded 75°. The extent to which the control forces from the ESP, or the potential distraction due to the system’s engagement and disengagement, may have contributed to the pilot’s failure to recover from the nose-low attitude following the stall could not be determined. FAA guidance warns of the risks associated with upset events during stall maneuvers and advises against performing accelerated stalls with flaps deployed due to the increased risk of exceeding the airplane’s limitations in this configuration. Following a nose-low departure from controlled flight, reducing the power to idle immediately is crucial to avoid exceeding airspeed limitations and overstressing the airplane. The circumstances of the accident flight are consistent with the pilot’s improper recovery from a nose-low attitude following an intentional aerodynamic stall. Whether the increase in torque following the stall was the result of intentional application of power by the pilot could not be determined; however, the pilot’s failure to reduce engine power to idle following the airplane’s departure from controlled flight was contrary to published guidance as well as test flight hazard mitigation procedures. It is likely that this resulted in the airplane’s rapid exceedance of its airspeed limitations, and subsequently, a structural failure and inflight breakup.

The single engine airplane was engaged in a local training flight at Puerto Ayacucho Airport, carrying five pilots. While completing a turn on approach to runway 04, the airplane went out of control and crashed in a wooded area located about 3 km south of the airport, bursting into flames. The airplane was totally destroyed by impact forces and a post crash fire and all five occupants were killed. Puerto Ayacucho Airport is named Cacique Aramare but the military side is named José Antonio Páez.
Crew:
Cpt José Castillo Tovar,
Cpt Jefferson Aular,
1st Lt Roberto Aponte,
Lt Santiago Collado,
Lt Joé Rivas.

The single engine airplane departed San Lorenzo at 0900LT on a flight to Tarapoto, carrying 10 passengers and two pilots. About 15 minutes into the flight, the crew encountered technical problems with the engine and attempted an emergency landing when the aircraft crash landed in a wooded area located some 15 km southeast of San Lorenzo. All 12 occupants were rescued and the aircraft was damaged beyond repair.

After takeoff from Porto Trombetas Airport, the pilot encountered engine problems and attempted an emergency landing. The airplane crashed in a wooded area and was destroyed. The pilot was killed and all four passengers were injured. They were en route to Ayaramã to provide dental assistance to locals. On board were one dentist, one assistant, one nurse and one employee of the Brazilian Institute for Geography and Statistics.

The pilots were performing skydiving flights while the right-seated pilot was training the left-seated pilot on the operation. The pilots completed six flights without incident and completed the drop of the skydivers on the accident flight normally. The right-seated pilot could not completely recollect the minutes leading up to the accident due to his injuries. He did recall that airplane was descending as expected with the power at idle. The recorded ADS-B data revealed that after turning onto final approach, the airplane then completed a right 360° turn presumably because the altitude was too high. The right-seated pilot attempted to increase the power by slightly nudging the throttle forward and thought the engine power did not increase as expected. A performance study revealed that in the last 70 seconds of recorded data, the airplane underwent a series of speed and thrust oscillations consistent with a pilot increasing and then decreasing the power lever. The right seat pilot recalls aiming for an open dirt field and observing a berm in the immediate flight path. In an effort to avoid the berm, he maneuvered the airplane into a right turn. The airplane landed short of the runway, resulting in a collision with the berm. The engine was producing power at the time of impact. Postaccident examination of the airplane revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. The right-seated pilot was in the process of training the left-seated pilot and stated that he took over the controls during the final approach. It is unknown when he took over the controls, so it is unknown which pilot was at the controls during the speed oscillations. The right-seated pilot likely took over the controls too late and the airplane impacted the terrain. The left-seated pilot’s ability to hear the changes in engine power might have been hindered because she was listening to music through her headset at an elevated decibel level. The airplane was modified by a Supplemental Type Certificate that replaces the original Pratt & Whitney PT-6 turbine engine with a Honeywell TPE331 turbine engine. The TPE331 engine’s characteristics are such that if the airplane is on final approach with the power near idle, the throttle sensitivity (change in thrust per unit of power lever movement) increases around the transition between the propellergoverning and underspeed-governing modes of the engine, which corresponds to a zero-thrust condition. Near this transition point, small movements of the power lever (about ¼ to ½ inch of deflection) can result in relatively large thrust changes that can surprise pilots inexperienced with this behavior and result in pilot-induced oscillations (PIO). Given the thrust oscillations observed shortly before the end of the ADS-B data, it is likely that the left-seated pilot was at the controls and experienced such a PIO on a short final approach to land.

The pilot flew two RNAV (GPS) runway 20 instrument approaches at the Burley Municipal Airport, Burley, Idaho in instrument meteorological conditions (IMC). The accident occurred during the second approach. For the first instrument approach, the pilot configured the airplane with flaps up and flew the final approach segment at speeds above the operator’s training standard of 120 knots indicated airspeed (KIAS).The pilot flew a low pass over the runway, most likely to assess the landing conditions in accordance with company policy, determined the conditions were acceptable, initiated the missed approach and requested to return flying the same approach. The pilot elected to not use flaps during the second approach but slowed the approach speed during the final approach leg. Reported weather had improved and visibility had increased to about 2.5 miles. During this approach, the airplane intercepted and remained on the glide path to the stepdown fix. The last automatic dependent surveillance - broadcast (ADS-B) equipment plot recorded the airplane about a mile past this fix, or about 0.6 nautical miles (nm) from the displaced threshold, on the glide path, and at an estimated 85 knots calibrated airspeed (KCAS), which was slower than the airplane’s 95-knot minimum speed for flaps up in icing conditions. Shortly afterward, the airplane descended about 130 ft below the glide path, striking an agglomerate stack atop a potato processing plant, fatally injuring the pilot and substantially damaging the airplane. A witness reported seeing the airplane come out of the clouds and immediately enter a steam cloud coming from six other stacks before striking the accident stack. A security camera at the processing plant captured the last moments of the airplane’s flight as it came into view in a wings-level, flaps-up, nose-high descent and just before it impacted the stack. While snow and visible moisture were present, the agglomerate stack was always in clear view during the Page 2 of 24 WPR22FA151 video, with only partial sections obscured. The witness’s account of hearing the engine noise increase and then the nose lift-up may have been the pilot’s attempt to avoid the obstacle. The Federal Aviation Administration’s (FAA) Aeronautical Information Manual advises pilots to avoid overflight of exhaust stacks; however, the accident stack was directly underneath the instrument approach course and overflight would be expected. Postaccident examination of the airplane, conducted hours after the accident, revealed no structural icing on the wings and empennage. Examination of the airframe and powerplant revealed no mechanical malfunctions or failures that would have precluded normal operation. The flaps were up, and a review of the manifest revealed the airplane was loaded within the specifications of the manifest and within the center of gravity limits. Between 2016 and 2017, the FAA conducted two aeronautical studies regarding the stack structures. In the first study, the FAA determined that many of the stack structures were a hazard to air navigation that required mitigation by the processing plant. As an interim measure, the FAA placed the runway 20 visual approach slope indicator (VASI) out of service because the stacks penetrated the obstruction clearance surface and were deemed hazardous to aviation. After determining that they needed to increase the height of the stacks, the plant then modified their proposal; the proposed height increase necessitated a second study. The second study determined the agglomerate stack and the row-of-six stacks exceeded the Code of Federal Regulations (CFR) section 77 standards and provided mitigating actions that included painting the stacks with high visibility white and aviation orange paint and equipping the stacks with red flashing warning lights. The control measures also included the permanent removal of the VASI. On the day of the accident, the agglomerate stack and row-of-six stacks had not been painted to the standard required by the FAA. The warning lights had been installed, and five of the row-of-six stacks were equipped with flashing red lights. The agglomerate stack warning light was stolen following the accident, so an accurate determination of its operating status could not be made. The existing paint scheme and the visible moisture emitted by the stacks provided a low contrast to the environmental background. This low contrast and the lack of a visual glide slope indicator may have caused difficulty for the pilot in maintaining a safe altitude during the visual portion of the approach to the runway. A white and aviation orange paint scheme, as identified in the regulations, may have offered a higher contrast and thus an adequate warning once the pilot transitioned to visual conditions.

The single engine airplane departed Moroni Airport at 1155LT on a schedule flight to Mohéli, carrying 12 passengers and two pilots. While approaching Mohéli, the crew encountered marginal weather conditions when the aircraft crashed in the sea some 2,5 km northwest of Mohéli-Bander es Eslam Airport. After 24 hours of intense research, only few debris were found floating on water (such a wheel and wing fragments). No trace of the 14 occupants was found.

A Cessna 208B airplane collided with a powered paraglider during cruise flight at 5,000 feet mean sea level (msl) in Class E airspace. Based on video evidence, the powered paraglider operator impacted the Cessna’s right wing leading edge, outboard of the lift strut attachment point. The outboard 10 ft of the Cessna’s right wing separated during the collision. The Cessna impacted terrain at high vertical speed in a steep nose-down and inverted attitude. The powered paraglider operator was found separated from his seat style harness. The paraglider wing, harness, and emergency parachute were located about 3.9 miles south of the Cessna’s main wreckage site. Based on video evidence and automatic dependent surveillance-broadcast (ADS-B) data, the Cessna and the powered paraglider converged with a 90° collision angle and a closing speed of about 164 knots. About 8 seconds before the collision, the powered paraglider operator suddenly turned his head to the right and about 6 seconds before the collision, the powered paraglider maneuvered in a manner consistent with an attempt to avoid a collision with the converging Cessna. Research indicates that about 12.5 seconds can be expected to elapse between the time that a pilot sees a conflicting aircraft and the time an avoidance maneuver begins. Additionally, research suggests that general aviation pilots may only spend 30-50% of their time scanning outside the cockpit. About 8 seconds before the collision (when the powered paraglider operator’s head suddenly turned to the right), the Cessna would have appeared in the powered paraglider operator’s peripheral view, where research has demonstrated visual acuity is very poor. Additionally, there would have been little apparent motion because the Cessna and the powered paraglider were on a collision course. Under optimal viewing conditions, the powered paraglider may have been recognizable to the Cessna pilot about 17.5 seconds before the collision. However, despite the powered paraglider’s position near the center of his field of view, the Cessna pilot did not attempt to maneuver his airplane to avoid a collision. Further review of the video evidence revealed that the powered paraglider was superimposed on a horizon containing terrain features creating a complex background. Research suggests that the powered paraglider in a complex background may have been recognizable about 7.4 seconds before the collision. However, the limited visual contrast of the powered paraglider and its occupant against the background may have further reduced visual detection to 2-3 seconds before the collision. Thus, after considering all the known variables, it is likely that the Cessna pilot did not see the powered paraglider with sufficient time to avoid the collision. The Cessna was equipped with a transponder and an ADS-B OUT transmitter, which made the airplane visible to the air traffic control system. The operation of the powered paraglider in Class E airspace did not require two-way radio communication with air traffic control, the use of a transponder, or an ADS-B OUT transmitter and therefore was not visible to air traffic control. Neither the Cessna nor the powered paraglider were equipped with ADS-B IN technology, cockpit display of traffic information, or a traffic alerting system. Postmortem toxicological testing detected the prescription antipsychotic medication quetiapine, which is not approved by the Federal Aviation Administration (FAA), in the Cessna pilot’s muscle specimen but the test results did not provide sufficient basis for determining whether he was drowsy or otherwise impaired at the time of the collision (especially in the absence of any supporting details to suggest quetiapine use). Testing also detected ethanol at a low level (0.022 g/dL) in the Cessna pilot’s muscle specimen, but ethanol was not detected (less than 0.01 g/dL) in another muscle specimen. Based on the available results, some, or all of the small amount of detected ethanol may have been from postmortem production, and it is unlikely that ethanol effects contributed to the accident. The Cessna pilot likely did not have sufficient time to see and avoid the powered paraglider (regardless of whether he was impaired by the quetiapine) and, thus, it is unlikely the effects of quetiapine or an associated medical condition contributed to the accident.

The single engine aircraft departed Dekai-Nop Goliat Airport for a short cargo flight to the Dagi Baru Airstrip with two pilots on board. Weather conditions were considered as good upon arrival. After landing, the aircraft went out of control, veered off runway and came to rest down a ravine. Both occupants were injured and the aircraft was destroyed.