Salt Lake City

The single engine airplane departed Reno-Tahoe Airport Runway 16L at 2058LT on an ambulance flight to Salt Lake City, carrying four passengers and one pilot. During initial climb, the pilot made two successive turns to the left according to the procedure then continued to the northeast. At 2113LT, at an altitude of 19,400 feet and at a speed of 191 knots, the airplane initiated a right turn then entered a spiraled descent and crashed one minute later in a snow covered prairie located southwest of Stagecoach. The airplane was destroyed by impact forces and all five occupants were killed, a pilot, a flight nurse, a flight paramedic, a patient and a patient’s family member.

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.

Shortly after takeoff, the pilot smelled smoke. As he began to turn the airplane back to the airport, the engine lost total power. He conducted a forced landing in a field just short of the airport, during which the airplane struck a metal fence and pipe. All occupants egressed, and the pilot then noticed that a fire had erupted under the airplane's engine cowling. Postaccident examination revealed that the airplane sustained fire damage to the roof and forward end of the baggage compartment along with the engine accessory area between the firewall and aft air baffles. Further examination revealed that one of the engine exhaust crossover pipe assemblies was misaligned at the slip joint. An engine manufacturer service bulletin (SB) called for inspections of the exhaust system slip and flange joints to identify misaligned exhaust components. The last maintenance event occurred about 7 1/2 flight hours before the accident, during which the SB was performed and resulted in the replacement of crossover pipes. The mechanic who had performed the most recent maintenance did not follow the correct procedures for reinstallation of the crossover pipe, and the inspector who reviewed his work did not examine the installation as it progressed but instead inspected the pipes after they were installed and essentially hidden from view by their protective heat shield. As a result of the misaligned engine exhaust crossover pipe, hot exhaust gases escaped into the engine compartment and started a fire, which compromised critical engine fuel and oil lines, and resulted in the loss of engine power.

The commercial pilot was departing on a routine positioning flight in dark night visual meteorological conditions. Footage from a security camera at the airport showed the airplane
take off normally and initiate a right turn, which was the established direction of traffic for the takeoff runway. The airplane continued the right turn, then entered an increasingly rapid descent and subsequently impacted terrain about 1 mile southwest from the airport. The wreckage distribution was consistent with a high-energy impact. Examination of the airframe and engine revealed no evidence of any preimpact mechanical malfunctions or anomalies that would have precluded normal operation. Autopsy and toxicology testing of the pilot did not reveal any evidence of impairment or incapacitation. Visual conditions prevailed in the area at the time of the accident; however, the setting Moon was obscured by cloud cover, and the airport was located in an area of remote, sparsely-populated high desert terrain. This would have resulted in few visual references to which the pilot could have oriented the airplane. Although the pilot had experience operating in this environment in night conditions and held an instrument rating, the circumstances of the accident are consistent with the known effects of spatial disorientation. The investigation could not determine the initiating event which led to the pilot's mismatch between the airplane's perceived and actual attitude; however, he likely experienced a sensory illusion as a result of spatial disorientation, which led to a loss of control.

The airline transport pilot departed in the twin-engine, turbine-powered airplane on an air ambulance flight with two medical crew members and a patient on board in night visual meteorological conditions. According to a witness, during the initial climb, the airplane made a left turn of about 30° from the runway heading, then stopped climbing, made an abrupt left bank, and began to descend. The airplane impacted a parking lot and erupted into flames. In the 2 months before the accident, pilots had notified maintenance personnel three times that the left engine was not producing the same power as the right engine. In response, mechanics had replaced the left engine's bleed valve three times with the final replacement taking place three days before the accident. In addition, about 1 month before the accident, the left engine's fuel control unit was replaced during trouble shooting of an oil leak. Post accident examination revealed that the right engine and propeller displayed more pronounced rotational signatures than the left engine and propeller. This is consistent with the left engine not producing power or being at a low power setting at impact. Further, the abrupt left bank and descent observed by the witness are consistent with a loss of left engine power during initial climb. The extensive fire and impact damage to the airplane precluded determination of the reason for the loss of left engine power.

The airline transport pilot and passenger departed on a cross-country flight in instrument meteorological conditions in the light business jet. About 1 minute after departure, air traffic control instructed the pilot to climb and maintain an altitude of 14,000 ft mean sea level (msl). About 3 minutes later, the pilot stated that the airplane's flight management system (FMS) had failed. Shortly thereafter, he requested a climb and stated that he was "trying to get to clear skies." Over the next several minutes, the controller provided the pilot with headings and altitudes to vector the airplane into visual meteorological conditions. During this time, and over the course of several transmissions, the pilot stated that he was "losing instruments," was hand-flying the airplane (likely indicating the autopilot was inoperative), and that he wanted to "get clear of the weather." Radar data indicated that, during the 10-minute flight, the airplane conducted a series of climbs and descents with large variations in airspeed. About 2 minutes before the loss of radar contact, the airplane entered a climbing right turn, reaching its highest altitude of about 21,000 ft, before it began a rapidly descending and tightening turn. Performance data revealed that, during this turn, the airplane entered a partially-inverted attitude, exceeded its design maneuvering speed, and reached a peak descent rate of about 36,000 ft per minute. Radar contact was lost at an altitude of about 16,000 ft msl, and the airplane subsequently experienced an inflight breakup. The wreckage was distributed over a debris path that measured about 3/4-mile long and about 1/3-mile wide. Postaccident examination and testing of various flight instruments did not indicate what may have precipitated the inflight anomalies that the pilot reported prior to the loss of control. Additionally, all airframe structural fractures were consistent with ductile overload, and no evidence of any preexisting condition was noted with the airframe or either engine. The airplane was equipped with three different sources of attitude information, all three of which were powered by separate sources. It is unlikely that all three sources would fail simultaneously. In the event the pilot experienced a dual failure of attitude instrumentation on both the pilot and copilot sides, airplane control could have been maintained by reference to the standby attitude indicator. Further, the pilot would have been afforded heading information from the airplane's standby compass. Although the pilot did not specifically state to the controller the nature of the difficulties he was experiencing nor, could the investigation identify what, if any, anomalies the pilot may have observed of the airplane's flight instruments, the pilot clearly perceived the situation as one requiring an urgent ascent to visual conditions. As a single pilot operating without the assistance of an additional crewmember in a high-workload, high-stress environment, the pilot would have been particularly susceptible to distraction and, ultimately, a loss of airplane control due to spatial disorientation.

The commercial pilot and copilot reported that, after a normal start and taxi, the airplane was cleared for takeoff. The pilot reported that he began the takeoff roll and, once the airplane reached 100 knots, he rotated the airplane. He added that the airplane immediately experienced an uncommanded right yaw and that the right rudder pedal was "at the floor." Both pilots applied pressure to the left rudder pedal; however, the pedal barely moved. The pilot then tried to manipulate the rudder trim; however, the airplane continued to yaw right. He then manipulated the throttle controls and landed the airplane on the left side of the runway. The airplane remained difficult to control, and subsequently, the left landing gear collapsed, and the airplane slid to a stop on its left side. Postaccident examination of the cockpit revealed that the rudder trim was fully trimmed to the nose right position. Examination of the rudder and rudder trim assembly revealed no anomalies that would have precluded normal operation. The reason for the unmanageable right yaw could not be determined.

Witnesses reported that the airplane’s takeoff ground roll appeared to be normal. Shortly after the airplane lifted off, it stopped climbing and yawed to the left. Several witnesses heard abnormal sounds, which they attributed to propeller blade angle changes. The airplane’s flight path deteriorated to a left skid and its airspeed began to slow. The airplane’s left bank angle increased to between 45 and 90 degrees, and its nose dropped to a nearly vertical attitude. Just before impact, the airplane’s bank angle and pitch began to flatten out. The airplane had turned left about 100 degrees when it impacted the ground about 1,500 feet from the midpoint of the 10,000-foot runway. A fire then erupted, which consumed the fuselage. Review of a security camera video of the takeoff revealed that the airplane was near the midpoint of the runway, about 140 feet above the ground, and at a ground speed of about 130 knots when it began to yaw left. The left yaw coincided with the appearance, behind the airplane, of a dark grayish area that appeared to be smoke. A witness, who was an aviation mechanic with extensive experience working on airplanes of the same make and model as the accident airplane, reported hearing two loud “pops” about the time the smoke appeared, which he believed were generated by one of the engines intermittently relighting and extinguishing. Post accident examination of the airframe, the engines, and the propellers did not identify any anomalies that would have precluded normal operation. Both engines and propellers sustained nearly symmetrical damage, indicating that the two engines were operating at similar low- to mid-range power settings at impact. The airplane’s fuel system was comprised of two separate fuel systems (one for each engine) that consisted of multiple wing fuel tanks feeding into a nacelle tank and then to the engine. The left and right nacelle tanks were breached during the impact sequence and no fuel was found in either tank. Samples taken from the fuel truck, which supplied the airplane's fuel, tested negative for contamination. However, a fuels research engineer with the United States Air Force Fuels Engineering Research Laboratory stated that water contamination can result from condensation in the air cavity above a partially full fuel tank. Both diurnal temperature variations and the atmospheric pressure variations experienced with normal flight cycles can contribute to this type of condensation. He stated that the simplest preventive action is to drain the airplane’s fuel tank sumps before every flight. There were six fuel drains on each wing that the Pilot’s Operating Handbook (POH) for the airplane dictated should be drained before every flight. The investigation revealed that the pilot’s previous employer, where he had acquired most of his King Air 200 flight experience, did not have its pilots drain the fuel tank sumps before every flight. Instead, maintenance personnel drained the sumps at some unknown interval. No witnesses were identified who observed the pilot conduct the preflight inspection of the airplane before the accident flight, and it could not be determined whether the pilot had drained the airplane’s fuel tank sumps. He had been the only pilot of the airplane for its previous 40 flights. Because the airplane was not on a Part 135 certificate or a continuous maintenance program, it is unlikely that a mechanic was routinely draining the airplane's fuel sumps. The witness observations, video evidence, and the postaccident examination indicated that the left engine experienced a momentary power interruption during the takeoff initial climb, which was consistent with a power interruption resulting from water contamination of the left engine's fuel supply. It is likely that, during the takeoff rotation and initial climb, water present in the bottom of the left nacelle tank was drawn into the left engine. When the water flowed through the engine's fuel nozzles into the burner can, it momentarily extinguished the engine’s fire. The engine then stopped producing power, and its propeller changed pitch, resulting in the propeller noises heard by witnesses. Subsequently, a mixture of water and fuel reached the nozzles and the engine intermittently relighted and extinguished, which produced the grayish smoke observed in the video and the “pop” noises heard by the mechanic witness. Finally, uncontaminated fuel flow was reestablished, and the engine resumed normal operation. About 5 months before the accident, the pilot successfully completed a 14 Code of Federal Regulations Part 135 pilot-in-command check flight in a King Air 90. However, no documentation was found indicating that he had ever received training in a full-motion King Air simulator. Although simulator training was not required, if the pilot had received this type of training, it is likely that he would have been better prepared to maintain directional control in response to the left yaw from asymmetrical power. Given that the airplane’s airspeed was more than 40 knots above the minimum control speed of 86 knots when the left yaw began, the pilot should have been able to maintain directional control during the momentary power interruption. Although the airplane’s estimated weight at the time of the accident was about 650 pounds over the maximum allowable gross takeoff weight of 12,500 pounds, the investigation determined that the additional weight would not have precluded the pilot from maintaining directional control of the airplane.

The commercial pilot was executing a precision instrument approach at night in instrument meteorological conditions when the airplane collided with terrain about four miles short of the runway. A review of air traffic control communications and radar data revealed the pilot was vectored onto the final approach course but never got established on the glide slope. Instead, he made a controlled descent below the glide slope as he proceeded toward the airport. When the airplane was five miles from the airport, a tower controller received an aural low altitude alert generated by the Minimum Safe Altitude Warning (MSAW) system. The tower controller immediately notified the pilot of his low altitude, but the airplane collided with terrain within seconds. Examination of the instrument approach system and onboard flight navigation equipment revealed no pre-mishap anomalies. A review of the MSAW adaptation parameters revealed that the tower controller would only have received an aural alarm for aircraft operating within 5 nm of the airport. However, the frequency change from the approach controller to the tower controller occurred when the airplane was about 10.7 miles from the airport, leaving a 5.7 mile segment where both controllers could receive visual alerts, but only the approach controller received an aural alarm. A tower controller does not utilize a radar display as a primary resource for managing air traffic. In 2004, the FAA changed a policy, which eliminated an approach controller's responsibility to inform a tower controller of a low altitude alert if the tower had MSAW capability. The approach controller thought the MSAW alarm parameter was set 10 miles from the airport, and not the 5 miles that existed at the time of the accident. Subsequent investigation revealed, that The FAA had improperly informed controllers to ensure they understood the alarm parameters for control towers in their area of responsibility. This led the approach controller to conclude that the airplane was no longer her responsibility once she handed it over to the tower controller. Plus, the tone of the approach controller's aural MSAW alarm was not sufficient in properly alerting her of the low altitude alert.

The Learjet 35A received substantial damage on impact with airport property and terrain during a landing overrun on runway 19 (7,002 feet by 150 feet, grooved asphalt) at Charles B. Wheeler Downtown Airport (MKC), Kansas City, Missouri. The airplane was operated by a commercial operator as a positioning flight to Kansas City International Airport (MCI), Kansas City, Missouri, with a filed alternate destination of Lincoln Airport (LNK), Lincoln, Nebraska. Night instrument meteorological conditions prevailed at the time of the accident. LNK was a certificated airport with a snow removal plan and was served by runway 17R (12,901 feet by 200 feet, grooved asphalt and concrete). The flight was en route to MCI to pick up passengers and continue on as an on-demand charter but diverted to MKC following the closure of MCI. MCI was closed due to a McDonnell Douglas MD83 sliding off a taxiway during an after landing taxi on contaminated runway/taxiway conditions. MKC held a limited airport certificate that did not have a snow removal plan and was served by runway 19. Following a precision approach and landing on runway 19 at MKC, the Learjet 35A slid off the departure end of the runway and impacted airport property and terrain. The Learjet 35A was operated with inoperative thrust reversers as per the airplane's minimum equipment list at the time of the accident. About 1:05 hours before the accident, runway 19 Tapley values were recorded as 21-22-22 with 1/2 inch of wet snow. About 17 minutes before the accident, MKC began snow removal operations. About 7 minutes before the accident, the MKC air traffic control tower (TWR) instructed the snow removal vehicles to clear the runway for inbound traffic. TWR was advised by airport personnel that runway 19 was plowed and surface conditions were 1/4 inch of snow of snow; friction values were not taken or reported. While inbound, the Learjet 35A requested any braking action reports from TWR. The first airplane to land was a Cessna 210 Centurion, and the pilot reported braking action to the TWR as "moderate", which was then transmitted by TWR as "fair" from a Centurion in response to the Learjet 35A's query. The Cessna 210 Centurion pilot did not use brakes during landing and did not indicate this to TWR during his braking action report. The Aeronautical Information Manual states that no correlation has been established between MU values and the descriptive terms "good," fair," and "nil" used in braking action reports. The Airport Winter Safety and Operations advisory circular (AC) states that "pilot braking action reports oftentimes have been found to vary significantly, even when reported on the same frozen contaminant surface conditions." The AC also states, "It is generally accepted that friction surveys will be reliable as long as the depth of snow does not exceed 1 inch (2.5 cm) and/or depth of wet snow/slush does not exceed 1/8 inch (3mm). The Learjet 35A flightcrew calculated a landing distance 5,400 feet. Two of the cockpit voice recording channels, which normally contain the pilot and copilot audio panel information, were blank.