Mountains

On July 10, 2021, about 1254 mountain standard time, a Beech C-90, turbo prop airplane, N3688P, was destroyed when it was involved in an accident near Wikieup, Arizona. The pilot and Air Tactical Group supervisor were fatally injured. The airplane was operated as a public use firefighting aircraft in support of the Bureau of Land Management conducting aerial reconnaissance and supervision. The airplane was on station for about 45 minutes over the area of the Cedar Basin fire. The ADS-B data showed the airplane had accomplished multiple orbits over the area of the fire about 2,500 ft above ground level (agl). The last ADS-B data point showed the airplane’s airspeed as 151 knots, its altitude about 2,300 ft agl, and in a descent, about 805 ft east southeast of the accident site. No distress call from the airplane was overheard on the radio. According to a witness, the airplane was observed in a steep dive towards the ground. The airplane impacted the side of a ridgeline in mountainous desert terrain. The main wreckage was mostly consumed by a post-crash fire. Debris was scattered over an area of several acres. Another witness observed the left wing falling to the ground after the aircraft had impacted the terrain. The left wing had separated outboard of the nacelle and was located about 0.79 miles northeast of the main wreckage and did not sustain thermal damage.

The twin engine airplane departed Villavicencio-La Vanguardia Airport at 0643LT on a training flight consisting with a proficiency check of the captain. On board were one instructor, one captain and one mechanic. About 22 minutes into the flight, while cruising over mountainous terrain in Instrument Meteorological Conditions, the airplane impacted trees and crashed on the slope of a hilly terrain located in the region of Restrepo. The wreckage was found three days later and all three crew members were killed.

The pilot was conducting an instrument flight rules cross-country flight and climbing to a planned altitude of 23,000 ft mean sea level (msl). According to air traffic control data, as the airplane climbed through 18,600 ft msl, its groundspeed was 171 knots, and a gradual reduction in groundspeed began. After reaching an altitude of about 20,200 ft msl, the airplane began a descent on a southeast heading. Just before the descent began, the airplane’s groundspeed had decreased to 145 knots. About 2 minutes after the descent began, the airplane turned right to a northeast heading on which it continued for about 30 seconds. The flightpath then became erratic before the data ended. The pilot made no distress calls and did not respond to repeated calls from the controller. The main wreckage of the airplane was located in densely forested terrain at an elevation of about 930 ft about 1,000 ft south of the last radar return. The outboard portion of the right wing, right aileron, right horizontal stabilizer, and right elevator were not located with the main wreckage and, despite ground and aerial searches with a small unmanned aircraft system, were not found. Examination of the wreckage indicated that the missing wing and tail sections separated in flight due to overload. Examination of the recovered airframe and engine did not reveal evidence of any pre-existing mechanical malfunctions or anomalies that would have precluded normal operation. Weather forecasts indicated that the accident site was in an area where moderate icing conditions up to 25,000 ft msl, embedded thunderstorms, and 2-inch hail were forecasted. Review of preflight weather information received by the pilot indicated that he was aware of the conditions forecast on the route of flight before initiating the flight. Meteorological data revealed that the airplane likely entered icing conditions that ranged from light to heavy as it climbed through 14,000 ft msl about 23 minutes after takeoff and remained in icing conditions for the remaining 16-minute duration of the flight. Freezing drizzle conditions were likely present along the flightpath. Although the airplane was equipped for flight in icing conditions, the pilot’s operating handbook contained a warning about flight into severe icing conditions, which stated that flight in freezing drizzle could result in ice build-up on protected surfaces exceeding the capability of the ice protection system. The airplane’s gradual loss of groundspeed as it climbed was consistent with ice accumulating on the airplane. It is likely that during the 16 minutes the airplane was operating in icing conditions, the capability of the ice protection system was exceeded, which resulted in a degradation of aircraft performance and subsequent aerodynamic stall. During the ensuing uncontrolled descent, the structural capability of the airplane was exceeded, which resulted in an inflight break up. A review of the pilot’s records revealed multiple certificate application failures for reasons that included inadequate knowledge of cross-country flight planning, aircraft performance, and stalls. Review of the pilot’s airman knowledge written tests found areas answered incorrectly over multiple exams included meteorology, aircraft performance, aeronautical decision-making, and stalls. The ethanol identified in the pilot’s cavity blood was most likely the result of postmortem production. Therefore, effects from ethanol did not play any role in this accident. The cargo was documented as it was removed from the airplane and remained secure until after it was weighed. Based upon the weight of the cargo, passengers, airplane, and fuel from the filed flight plan, at the time of departure, the airplane would have been about 361 lbs over maximum gross weight. According to the FAA Pilot’s Handbook of Aeronautical Knowledge, an overloaded airplane “may exhibit unexpected and unusually poor flight characteristics,” which include reduced maneuverability and an increased stall speed.

The report describes the accident to C208B type of aircraft, registration 5Y-JKN with two crew on onboard that occurred on Marsabit Hill on 20th March 2021 in which the aircraft crashed killing two crew onboard. The aircraft with 2200lbs fuel onboard was chartered to ferry Marsabit County Officials to a peace keeping mission at Illeret 156 nautical miles North West of Marsabit town. Preliminary information revealed that the aircraft departed Wilson Airport at 08.20am (0520Z) and arrived within the vicinity of Marsabit town at around 10.00a.m (0700Z). It collided with Kofia Mbaya Hill - Marsabit terrain while attempting to approach Marsabit airstrip. The aircraft first impacted the terrain with its nose-wheel and the main landing gears leaving parts of the fuselage and iron box with its content kept in the lower baggage compartment on the sport. It then ballooned and missed a house before it flipped upside down and impacted the ground and came to rest facing opposite direction. It left a trail of aircraft parts along its path before it came to rest. The nosewheel and its assembly separated and fell off and was found next to the house 110m from its first point of impact. There was no fire after impact but all the occupants received fatal injuries.

The non-instrument-rated pilot departed on a cross-country flight. Radar track data revealed the airplane traveled on a relatively straight course to the northeast for about 32 minutes. Near the end of the flight track data, the track showed an increasingly tight left spiraling turn near the accident site. The airplane impacted steep sloping terrain, and a postimpact fire ensued. As a result of the impact, the airplane was segmented into several sections. Examination of the wreckage revealed no evidence of mechanical malfunction or failures that would have precluded normal operation. The attitude indicator instrument was disassembled, and the vacuum-powered rotor and housing revealed rotational scoring damage, indicating the instrument vacuum system was operational at the time of the accident. The investigation found no evidence indicating the pilot checked the weather or received weather information before departure. The surrounding weather reporting stations near the accident site reported wind conditions with peak gusts up to 47 knots around the time of the accident. The pilot likely encountered mountain wave activity with severe turbulence, which resulted in loss of control of the airplane and impact with terrain. Contributing to the accident was the pilot’s failure to obtain a preflight weather briefing, which would have alerted him to the presence of hazardous strong winds and turbulent conditions. Postmortem toxicology testing of the pilot’s lung and muscle tissue samples detected several substances that are mentally and physically impairing individually and even more so in combination for performing hazardous and complex tasks. However, blood concentrations are needed to determine the level of impairment, and no blood samples for the pilot were available. While the pilot was taking potentially impairing medications and likely had conditions that would influence decision making and reduce performance, without blood concentrations, it was not possible to determine whether the potentially impairing combination of medications degraded his ability to safely operate the airplane.

The pilot was conducting a cross-country flight and was beginning an instrument flight rules approach from the south. Weather conditions at the destination airport included a ceiling between 800 and 1,000 ft and light rime icing conditions in clouds; the pilot was aware of these conditions. Elevated, wooded terrain existed along the final approach course. Radar and automatic dependent surveillance-broadcast data revealed that the airplane crossed the intermediate approach fix at the correct altitude; however, the pilot descended the airplane below the final approach fix altitude about 4 miles before the fix. The airplane continued in a gradual descent until radar contact was lost. No distress calls were received from the airplane before the accident. The airplane crashed on a north-northwesterly heading about 5 miles south of the runway threshold. The elevation at the accident site was about 1,880 ft, which was about 900 ft higher than the airport elevation. Postaccident examination of the airframe, engines, and propellers revealed no evidence of a pre-existing mechanical failure or anomaly that would have precluded normal operation. Because of the weather conditions at the time of the final approach, the pilot likely attempted to fly the airplane under the weather to visually acquire the runway. The terrain along the final approach course would have been obscured in low clouds at the time, resulting in controlled flight into terrain.

On approach to Voi Airport, the twin engine aircraft struck the slope of Mt Irima located about 9 km north from runway 18 threshold. All four occupants were killed. Registration unconfirmed.

During the first 15 minutes of the flight, the pilot of the complex, high performance, jet airplane appeared to have difficulty maintaining the headings and altitudes assigned by air traffic controllers, and throughout the flight, responded intermittently to controller instructions. After reaching an altitude of 27,000 ft, the airplane began to deviate about 30° right of course while continuing to climb. The controller alerted the pilot, who did not respond, and the airplane continued to climb. Two minutes later, the airplane entered a tight, spiraling descent that lasted 8 minutes until the airplane impacted the ground at high speed in a rightwing-low attitude. The airplane was highly fragmented on impact; however, examination did not reveal any evidence of structural failure, in-flight fire, a bird strike, or a cabin depressurization event, and both engines appeared to be producing power at impact. Although the 72-year-old private pilot had extensive flight experience in multiple types of aircraft, including jets, he did not hold a type rating in the accident airplane, and the accident flight was likely the first time he had flown it solo. He had received training in the airplane about two months before the accident but was not issued a type rating and left before the training was complete. During the training, he struggled significantly in high workload environments and had difficulty operating the airplane’s avionics suite, which had recently been installed. He revealed to a fellow pilot that he preferred to “hand fly” the airplane rather than use the autopilot. The airplane’s heading and flight path before the spiraling descent were consistent with the pilot not using the autopilot; however, review of the flight path during the spiraling descent indicated that the speed variations appeared to closely match the airplane’s open loop phugoid response as documented during manufacturer flight tests; therefore, it is likely that the pilot was not manipulating the controls during that time.

The pilot, sole on board, departed Flandes-Santiago Vila Airport runway 02 at 1257LT on a flight to Guaymaral in Bogotá. En route, weather conditions worsened and the visibility was poor. While cruising at an altitude of 9,260 feet, the twin engine airplane impacted trees and crashed in a wooded and hilly terrain located near Bojacá. The aircraft was destroyed by impact forces and the pilot was killed.

While descending to Bukavu-Kavumu Airport on a flight from Kalima, the crew encountered poor visibility due to fog. Seven minutes prior to ETA, the aircraft struck trees and crashed in a wooded and mountainous area located in the Kahuzi-Miega National Park. The wreckage was found about 15 km south of the airport. All four occupants were killed.