United States of America

On August 10, 2018, about 2043 Pacific daylight time, a De Havilland DHC-8-402, N449QX, was destroyed when it impacted trees on Ketron Island, near Steilacoom, WA. The noncertificated pilot was fatally injured. The airplane was registered to Horizon Air Industries, Inc,. and was being operated by the noncertificated pilot as an unauthorized flight. Visual meteorological conditions prevailed in the area at the time of the event, and no flight plan was filed. The airplane departed from the Seattle-Tacoma International Airport, Seattle, Washington, about 1932. Horizon Air personnel reported that the noncertificated pilot was employed as a ground service agent and had access to the airplanes on the ramp. The investigation of this event is being conducted under the jurisdiction of the Federal Bureau of Investigation (FBI). The NTSB provided requested technical assistance to the FBI, and any material generated by the NTSB is under the control of the FBI. The NTSB does not plan to issue an investigative report or open a public docket.

The pilot and four passengers were nearing the completion of a cross-county business flight. While maneuvering in the traffic pattern at the destination airport, the controller asked the pilot if he could accept a shorter runway. The pilot said he could not, so he was instructed to enter a holding pattern for sequencing; less than a minute later, the pilot said he could accept the shorter runway. He was instructed to conduct a left 270° turn to enter the traffic pattern. The pilot initiated a left bank turn and then several seconds later the bank increased, and the airplane subsequently entered a steep nose-down descent. The airplane impacted a shopping center parking lot about 1.6 miles from the destination airport. A review of the airplane's flight data revealed that, shortly after entering the left turn, and as the airplane’s bank increased, its airspeed decreased to about 59 knots, which was well below the manufacturer’s published stall speed in any configuration. Postaccident examination of the airframe and engines revealed no anomalies that would have precluded normal operation. It is likely that the pilot failed to maintain airspeed during the turn, which resulted in an exceedance of the aircraft's critical angle of attack and an aerodynamic stall.

The commercial pilot was conducting a 1-hour commercial air tour flight over Denali National Park and Preserve with four passengers on board. About 48 minutes after departure, the Alaska Rescue Coordination Center received an alert from the airplane's emergency locator transmitter. About 7 minutes later, company personnel received a call from the pilot, who reported that the airplane had run "into the side of a mountain." Although a search was initiated almost immediately, due to poor weather conditions in the area, the wreckage was not located until almost 36 hours later in a crevasse on a glacier about 10,920 ft mean sea level. Due to the unique challenges posed by the steepness of terrain, the crevasse, avalanche hazard, and the condition of the airplane, neither the occupants nor the wreckage were recovered from the accident site. A weather model sounding for the area of the accident site estimated broken cloud bases at 700 ft above ground level (agl) with overcast clouds at 1,000 ft agl and cloud tops to 21,000 ft agl and higher clouds above. The freezing level was at 9,866 ft and supported light-to-moderate rime type icing in clouds and precipitation. The on-scene assessment indicated that the right wing impacted snow while the airplane was flying in a wings-level attitude; the right wing had separated from the remainder of the wreckage. Based upon available weather data and forecast models and the impact evidence, it is likely that the pilot entered an area of reduced visibility and was unable to see the terrain before the airplane's right wing impacted the snow. The company's organizational structure was such that one group of management personnel oversaw operations in both Anchorage and Talkeetna. Interviews with company management revealed that they were not always aware of the exact routing a pilot would take for a tour; the route was pilot's discretion based upon the weather at the time of the flight to provide the best tour experience. Regarding risk mitigation, the company did not utilize a formal risk assessment process, but rather relied on conversations between pilots and flight followers. This could lead to an oversight of actual risk associated with a particular flight route and weather conditions. About 8 months after the accident, an assessment flight conducted by the National Park Service determined that during the winter, the hazardous hanging glacier at the accident site calved, releasing an estimated 4,000 to 6,000 tons of ice and debris. There was no evidence of the airplane wreckage near the crash site, in the steep fall line, or on the glacier surface over 3,600 ft below. Although the known circumstances of the accident are consistent with a controlled flight into terrain event, the factual information available was limited because the wreckage was not recovered and no autopsy or toxicology of the pilot could be performed; therefore, whether other circumstances may have contributed to the accident could not be determined.

The pilot was conducting a personal flight with four passengers. A witness observed the airplane take off and climb slowly from the airport. A pilot flying in the vicinity observed the airplane maneuver erratically before the airplane impacted terrain in a near-vertical attitude. The airplane was destroyed by impact forces and a postimpact fire. The wreckage was contained to a confined area in the field and the remains of the major airplane components were all accounted for. Extensive thermal damage to the airframe and engine limited the scope of the postaccident examination. The impact energy needed to drive the engine into the ground suggested that the engine was producing power at the time of the accident. A postaccident examination of the remaining airframe and engine components did not reveal any anomalies which would have precluded normal operation of the airplane. Depending on the amount of fuel, baggage and equipment on board, and the location of the adult passenger, the center of gravity (CG) could have been within or aft of the recommended CG. Since fuel load and location of the passengers could not be determined or may have shifted during flight, it is not known if loading contributed to the accident. The pilot was not operating with valid medical certification. His second-class medical certificate had expired several years prior to the accident and Federal Aviation Administration records did not indicate that he had obtained BasicMed medical certification. A pilot-rated passenger was seated in the rightfront seat. Investigators were unable to determine who was manipulating the flight controls of the airplane at the time of the accident. The circumstances of the accident are consistent with the pilot’s loss of control. However, the reason for the loss of control could not be determined with the available evidence.

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.

According to the copilot, before takeoff, he and the pilot had briefed that the copilot would conduct the takeoff for the planned cross-country flight and be the pilot flying and that the pilot would be the pilot monitoring. The accident flight was the copilot's first takeoff in the accident airplane with it at or near its maximum gross weight. The pilot reported that he taxied the airplane onto the runway and locked the tailwheel in place and that the copilot then took over the controls. About 13 seconds after the start of the takeoff roll, the airplane veered slightly right, and the copilot counteracted with left rudder input. The airplane then swerved left, and shortly after the pilot took control of the airplane. The airplane briefly became airborne; the pilot stated that he knew the airplane was slow as he tried to ease it back over to the runway and set it back down. Subsequently, he felt the shudder “of a stall,” and the airplane rolled left and impacted the ground, the right main landing gear collapsed, and the left wing struck the ground. After the airplane came to a stop, a postimpact fire ensued. All the airplane occupants egressed through the aft left door. Postaccident examination of the airplane revealed no evidence of any mechanical malfunctions or failures with the flight controls or tailwheel. Both outboard portions of the of the aluminum shear pin within the tailwheel strut assembly were sheared off, consistent with side load forces on the tailwheel during the impact sequence. The copilot obtained his pilot-in-command type rating and his checkout for the accident airplane about 2 months and 2 weeks before the accident, respectively. The copilot had conducted two flights in the accident airplane with a unit instructor before the accident. The instructor reported that, during these flights, he noted that the copilot had directional control issues; made "lazy inputs, similar to those for small airplanes"; tended to go to the right first; and seemed to overcorrect to the left by leaving control inputs in for too long. He added that, after the checkout was completed, the copilot could take off and land without assistance; however, he had some concern about the his reaction time to a divergence of heading on the ground. Given the evidence, it is likely the copilot failed to maintain directional control during the initial takeoff roll. It is also likely that, if the pilot, who had more experience in the airplane, had monitored the copilot's takeoff more closely and taken remedial action sooner, he may have been able to correct the loss of directional control before the airplane became briefly airborne and subsequently experienced an aerodynamic stall.

The mechanic who maintained the airplane reported that, on the morning of the accident, the right engine would not start due to water contamination in the fuel system. The commercial pilot and mechanic purged the fuel tanks, flushed the fuel system, and cleaned the left engine fuel injector nozzles. After the maintenance work, they completed engine ground runs for each engine with no anomalies noted. Subsequently, the pilot ordered new fuel from the local fixed-based operator to complete a maintenance test flight. The pilot stated that he completed a preflight inspection, followed by engine run-ups for each engine with no anomalies noted and then departed with one passenger onboard. Immediately after takeoff, the right engine stopped producing full power, and the airplane would not maintain altitude. No remaining runway was left to land, so the pilot conducted a forced landing to a field about 1 mile from the runway; the airplane landed hard and came to rest upright. Postaccident examination revealed no water contamination in the engines. Examination of the airplane revealed numerous instances of improper and inadequate maintenance of the engines and fuel system. The fuel system contained corrosion debris, and minimal fuel was found in the lines to the fuel servo. Although maintenance was conducted on the airplane on the morning of the accident, the right engine fuel injectors nozzles were not removed during the maintenance procedures; therefore, it is likely that the fuel flow volume was not measured. It is likely that the corrosion debris in the fuel system resulted when the water was recently purged from the fuel system. The contaminants were likely knocked loose during the subsequent engine runs and attempted takeoff, which subsequently blocked the fuel lines and starved the right engine of available fuel.

The pilot was conducting an on-demand air taxi flight in a float-equipped airplane from a seaplane base on a public lake to a remote lakeside home, with a passenger and her young son. The passenger brought cargo to transport as well, including an unexpected 800 lbs of mortar bags. Witnesses who labored to push the airplane out after loading reported that the airplane appeared very aft heavy and the pilot said he would offload "cement blocks" if he could not take off. A review of witness videos revealed that the pilot attempted one takeoff using only 3/4 of the available waterway, then step taxied around the lake and performed a step-taxi takeoff, again not using the full length of the lake. The airplane eventually lifted off, and barely climbed over trees on the south end of the lake, before descending and impacting terrain. A home surveillance video that captured the airplane seconds before the crash revealed that 3 seconds before ground impact, the estimated altitude of the airplane was 115 ft above ground level (agl) and the groundspeed was about 64 miles per hour (mph), which was low and much slower than normal climb speed (80 mph). As the airplane banked to the left to turn on course, it rolled through 90° likely experiencing an aerodynamic stall. Analysis of the engine rpm sound revealed that the engine was operating near maximum continuous power up until impact, and a postaccident examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. A calculation performed by investigators postaccident revealed the airplane's estimated gross weight at the time of the accident was 75 lbs over the approved maximum gross takeoff weight, and the airplane's estimated center of gravity was 1.76 inches aft of the rear limit. The pilot had been recently hired by the operator and he flew his first commercial flight in the same make and model, float-equipped airplane the week before the accident. He had accumulated 12.9 flight hours, and 13 sea landings/takeoffs in the accident model airplane since being hired as a part-time pilot. Although the airplane was able to takeoff, the aircraft's out-of-limit weight-and-balance condition increased its stall speed and degraded its climb performance, stability, and slow-flight characteristics. When the pilot turned the airplane left, the critical angle of attack was exceeded resulting in an aerodynamic stall at low altitude. If the pilot had performed a proper weight and balance calculation, he may have recognized the airplane was overweight and out of balance and should not have attempted the flight without making a load adjustment.

The pilot reported that, following a precautionary shutdown of the No. 2 engine, he diverted to an alternate airport that was closer than the original destination. During the landing in tailwind conditions, the airplane touched down "a little fast." The pilot added that, as the brakes faded from continuous use, the airplane was unable to stop, and it overran the end of the runway, which resulted in substantial damage to the fuselage. The pilot reported that there were no mechanical malfunctions or failures with the airplane that would have precluded normal operation.

The airline transport pilot was conducting a commercial visual flight rules (VFR) flight transporting 10 passengers from a remote fishing lodge. According to the pilot, while in level cruise flight about 1,100 ft mean sea level (msl) and as the flight progressed into a mountain pass, visibility decreased rapidly. In an attempt to turn around and return to VFR conditions, the pilot initiated a climbing right turn. Before completing the 180° right turn, he saw what he believed to be a body of water and became momentarily disoriented, so he leveled the wings. Shortly thereafter, he realized that the airplane was approaching an area of snow-covered mountainous terrain, so he applied full power and initiated a steep climb; the airspeed decayed, and the airplane collided with an area of rocky, rising terrain, which resulted in substantial damage to the wings and fuselage. The pilot reported no mechanical malfunctions or anomalies that would have precluded normal operation, and the examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. The weather forecast at the accident time included scattered clouds at 2,500 ft msl, overcast clouds at 5,000 ft msl with cloud tops to 14,000 ft and clouds layered above that to flight level 250, and isolated broken clouds at 2,500 ft with light rain. AIRMET advisory SIERRA for "mountains obscured in clouds/precipitation" was valid at the time of the accident. Conditions were expected to deteriorate. Passenger interviews revealed that through the course of the flight, the airplane was operating in marginal visual meteorological conditions and occasional instrument meteorological conditions (IMC) with areas of precipitation, reduced visibility, obscuration, and, at times, little to no forward visibility. Thus, based on weather reports and forecasts, and the pilot's and passengers' statements, it is likely that the flight encountered IMC as it approached mountainous terrain and that the pilot then lost situational awareness. The airplane was equipped with a terrain awareness and warning system (TAWS); however, the alerts were inhibited at the time of the accident. Although the TAWS was required to be installed per Federal Aviation Administration (FAA) regulations, there is no requirement for it to be used. All company pilots interviewed stated that the TAWS inhibit switch remained in the inhibit position unless a controlled flight into terrain (CFIT) escape maneuver was being accomplished. However, the check airman who last administered the accident pilot's competency check stated that the TAWS inhibit switch was never moved, even during a CFIT escape maneuver. The unwritten company policy to leave the TAWS in the inhibit mode and the failure of the pilot to move the TAWS out of the inhibit mode when weather conditions began to deteriorate were inconsistent with the goal of providing the highest level of safety. However, if the pilot had been using TAWS, due to the fact that he was operating at a lower altitude and thus would have likely received numerous nuisance alerts, the investigation could not determine the extent to which TAWS would have impacted the pilot's actions. At the time of the accident, the director of operations (DO) for the company resided in another city and served as DO for another air carrier as well. He traveled to the company's main base of operation about once per month but was available via telephone. According to the chief pilot, he had assumed a large percentage of the DO's duties. The president of the company said that the chief pilot had taken over "officer of the deck" and "we're just basically using him [the DO] for his recordkeeping." The FAA was aware that the company's DO was also DO for another commuter operation. FAA Flight Standards District Office management and principal operations inspectors allowed him to continue to hold those positions, although it was contrary to the guidance provided in FAA Order 8900.1. The company's General Operations Manual (GOM) only listed the DO, the chief pilot, and the president by name as having the authority to exercise operational control. However, numerous company personnel stated that operational control could be and was routinely delegated to senior pilots. The GOM stated that the DO "routinely" delegated the duty of operational control to flight coordinators, but the flight coordinator on duty at the time of the accident stated that she did not have operational control. In addition, the investigation revealed numerous inadequate and missing operational control procedures and processes in company manuals and operations specifications. Based on the FAA's inappropriate approval of the DO, the insufficient company onsite management, the inadequate operational control procedures, and the exercise of operational control by unapproved persons likely resulted in a lack of oversight of flight operations, inattentive and distracted management personnel, and a loss of operational control within the air carrier. However, the investigation could not determine the extent to which any changes to operational control, company management, and FAA oversight would have influenced the pilot's decision to continue the VFR flight into IMC.