South Lake Tahoe, CA, USA
N8718X
CESSNA 182D
The noninstrument-rated private pilot was returning to his home airport along a mountainous route that he had traveled multiple times in the accident airplane. After landing for fuel at an intermediate airport, he called his wife and reported that the landing was challenging due to strong winds. He subsequently departed on the final leg of the flight, and shortly after departure, he sent her in-flight photographs which revealed limited visibility, dust storms, and lenticular cloud formations in the general direction of his intended route. The flight progressed on a relatively constant track for the next 2 hours, during which time the airplane encountered significant headwinds, which reduced its ground speed to about half of its typical cruise speed. As the airplane approached the high terrain of the Sierra Nevada mountain range, the flight track began to deviate left and right with rapid climbs and descents. During the last 1.5 minutes of flight, the airplane descended from 10,800 ft to the last radar-recorded altitude of 9,700 ft. Snow, rain, and strong wind hampered the search effort, and the wreckage was found 3 days after the accident covered in snow at an elevation of 8,630 ft, about 3,300 ft south of the last radar target and about 50 miles short of the destination airport. The debris field and airframe damage was consistent with a high-speed, right-wing-low impact. The airplane was equipped with a 406MHz emergency locator transmitter (ELT), which should have provided search and rescue teams with an accurate location of the wreckage, however, due to the severity of the impact, the ELT detached from the airframe and thereby its antenna. The pilot's injuries were determined to be non-survivable. Examination of the airframe and engine did not reveal any anomalies that would have precluded normal operation. About 30 minutes before the accident, an air traffic controller issued the pilot a frequency change, which the pilot read back correctly. Although the airplane's flight path continued, the pilot never made radio contact with the next controller, and neither that controller nor the previous controller was able to reach the pilot despite numerous attempts. It is possible that, during this portion of the flight, the pilot was occupied with maintaining control as the airplane began to experience the effects of downdrafts and mechanical turbulence while approaching mountainous terrain from the lee side. A storm was passing through the area at the time of the accident with high winds, mountain obscuration, and precipitation; these conditions were both predicted and widely disseminated in published weather products. Weather analysis revealed that, during the final minutes of flight, the airplane likely either entered or was drawn into instrument meteorological and airframe icing conditions after encountering downdrafts with velocities that exceeded the airplane's climb capability. It could not be determined whether the impact was the result of spatial disorientation after entering the instrument conditions, the encounter with downdraft conditions, or some combination of the two. Additionally, the pilot did not use his shoulder harness, and his lap belt appeared to be loose at the time of impact. He had struck his head on the cabin roof during a prior turbulence encounter, so it is possible that this happened again, leading to some form of incapacitation during the final minutes of the flight. Furthermore, none of the airplane's cargo, including folding chairs, water canisters, coolers, tools, and clothing had been secured. These items most likely began to shift during the downdraft encounters, possibly becoming a distraction, or even interfering with the pilot. Although the pilot did not receive an official weather briefing before the accident flight, he was likely using a tablet-based mobile application and ADS-B device that would have provided him with weather information; additionally, conversations with his wife about the flight and interactions with air traffic control personnel regarding a temporary flight restriction (TFR) in the area indicated that he had a source of aviation weather and flight information. After departing on the flight, the high wind conditions were apparent to the pilot given the airplane's slow ground speed, and the lenticular cloud conditions reflected the presence of mountain wave activity. Additionally, pilots on the air traffic control approach frequency that the pilot was tuned to were discussing landing options given the high wind conditions in the area. The presence of clouds at and above his flight level during the latter parts of the flight would have been obvious to the pilot. The worsening weather conditions in the region (in particular the extreme surface winds at area airports), along with the TFR, which was located just below the final segment of his route before crossing over a large lake and into remote, mountainous terrain, may have contributed to the pilot's reluctance to discontinue the flight and land. Additionally, his familiarity with the area and route, along with the relative close proximity of his destination, may have lulled him into a false sense of security, predisposing him to continue the flight.
HISTORY OF FLIGHTOn October 15, 2016, at 1552 Pacific daylight time, a Cessna 182D airplane, N8718X, impacted the northeast face of Red Peak in the Desolation Wilderness near South Lake Tahoe, California. The private pilot sustained fatal injuries, and the airplane was destroyed. The airplane was registered to and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91. Instrument meteorological conditions prevailed in the area of the accident site, and no flight plan was filed for the personal flight, which departed Winnemucca Municipal Airport (WMC), Winnemucca, Nevada, about 1320, with a planned destination of Westover Field/Amador County Airport (JAQ), Jackson, California. The pilot was returning from a hunting trip, and initially departed Lemhi County Airport (SMN), Salmon, Idaho, on the morning of the accident. He landed at WMC, where he serviced the airplane with 41 gallons of 100LL aviation gasoline. Before departing, he spoke with his wife and stated that the landing at WMC was challenging due to gusting wind conditions. After departing on the accident flight, the pilot took two digital photographs, which he sent to his wife as text messages. The photographs were taken at 1329 and 1336, and their GPS-derived positions and altitudes were contained within the metadata. The photographs were taken about 9 and 18 miles southwest of WMC at altitudes of 6,755 ft and 8,986 ft, respectively, and included views to the south-southeast. (See figures 1 and 2.) The photographs captured areas of mountainous terrain with peaks that appeared about level with the airplane's altitude. Dust clouds could be seen in an adjacent valley, with the dust reaching elevations above the airplane. To the south, in the general direction of the flight, the area was enveloped with dust and/or virga. Both photographs included overcast cloud layers, with openings to the south, through which multiple layers of lenticular clouds could be seen. Figures 1. 2. Photographs Taken by the Pilot at 1329 (left) and 1336 (right). At 1338, Air Route Surveillance Radar based in Fallon, Nevada, acquired a target which was using a transponder code of 1200 and traveling southwest at a mode C reported altitude of 9,500 ft, which corresponded with the airplane's position and route. During the next 13 minutes, after passing 6 miles north of the 9,836 ft summit of Star Peak, the target made a 360° left turn descending to 7,600 ft and then climbing back to 8,600 ft. The target then proceeded southwest for the next hour at altitudes ranging between 8,700 ft and 11,200 ft; at 1450, the pilot's wife received a text message from the pilot stating that he was at Pyramid Lake, and "79 knots." The target reached the northeast outskirts of Reno, Nevada, at 1454; about that time, the pilot initiated radio contact with Oakland Air Route Traffic Control Center (ZOA), and requested visual flight rules (VFR) flight following. He was provided a transponder code of 3726, and a few seconds later, the 1200 code target switched to a code of 3726. The airplane continued on the southwesterly track, and at 1457, the ZOA controller provided the pilot with a new frequency, transferring the airplane to Northern California Terminal Radar Approach Control (NCT). After establishing radio contact with NCT, the pilot reported his altitude (10,600 ft) and destination and was provided an altimeter setting. About 2 minutes later, the pilot of an Air Tractor AT-802 (callsign Tanker 874) reported over the same frequency that he was over Pyramid Lake (about 14 miles north of the accident airplane's location) at 8,200 ft and was inbound for "Reno" airport. The pilot of an Aero Commander 690A airplane then reported to NCT that he was also over Pyramid Lake, was inbound for Reno/Stead Airport, and was looking for Tanker 874. Over the next few minutes, the NCT controller issued a wind advisory to Tanker 874 for Reno International Airport, reporting wind from 200° at 31 knots, gusting to 41 knots. The pilot of Tanker 874 stated that his intention was to land at Reno/Stead Airport, rather than Reno-Tahoe International Airport, but that the wind was "not good". He stated that he would track the progress of the Aero Commander, and then divert to Reno International if the wind conditions were not favorable. During those communications, the accident airplane progressed at an altitude of about 10,700 ft while remaining on a track of 220° and a ground speed of about 60 knots. At 1507, the accident pilot asked the NCT controller if a temporary flight restriction (TFR) over Carson City, Nevada, was still in effect. The controller responded that it was, but that it should not be a factor because the TFR ceiling was 10,000 ft. (See figure 3.) Figure 3. Temporary Flight Restriction (green) Underneath the Route of Flight By 1522, the accident airplane was 12 miles south of Reno, and the NCT controller initiated a handoff back to ZOA and provided the pilot with the appropriate frequency. The pilot read back the frequency correctly; however, the pilot did not contact ZOA. The airplane continued on the same general southwesterly track; over the next 29 minutes, the ZOA controller made four attempts to contact the pilot and requested that NCT do the same. No response was received by either facility, and radar contact was lost at 1551. Review of the radar data indicated that, at 1543, as the airplane crossed the western shore of Lake Tahoe (elevation 6,229 ft) within about 8 miles of the peaks of the Desolation Wilderness area (elevation 9,983 ft), it began to veer left and then right with accompanying oscillations in altitude between 10,100 ft and 10,900 ft. For the last 96 seconds, the airplane descended from 10,800 ft to the last recorded altitude of 9,700 ft, about 3/4-mile northeast of the 9,311-ft summit of Red Peak. (See figure 4.) Figure 4. Flight Path During the Final Stages of Flight (the white lines are direct connections between each acquired radar target and do not represent the airplane's actual flight path between targets) Controllers from both facilities continued their attempts to establish contact with the pilot, and with no response, an alert notice (ALNOT) was issued at 1839. Review of the radar data for the last 2 hours of flight indicated that the airplane traveled a straight-line distance about 135 miles, which yielded a ground speed that was about half the airplane's normal cruise speed. (See figure 5.) Figure 5. Radar-acquired Route of Flight (blue indicates 1200 transponder code, red indicates 3726 transponder code) Snow, rain, and strong wind conditions hampered the search effort, and the wreckage was discovered 3 days later, covered in snow at an elevation of 8,630 ft, about 3,300 ft south of the last radar target and about 50 miles from the destination airport, JAQ. PERSONNEL INFORMATIONThe pilot held a private pilot certificate with an airplane single-engine land rating, issued in 1988. He held a third-class Federal Aviation Administration (FAA) medical certificate issued on February 16, 2015, with no limitations or waivers. He did not hold an instrument rating. Review of the pilot's logbook revealed a total flight experience of 1,151.6 hours as of July 2, 2016. Most of his experience was in the accident airplane, which he purchased in 2005. His most recent flight review was on May 3, 2015, in the accident airplane. According to the pilot's wife, the pilot typically flew between California and Idaho six or seven times per year, which required crossing the Sierra Nevada mountain range. His mountain flying experience also included multiple trips requiring passage over the Trinity Alps, Marble Mountains, the Cascades, and the mountainous terrain of southern California, South Dakota, Wyoming, Montana, and Washington. According to his wife, the accident flight was one of the rare times he flew without a passenger. She stated that, on occasion, they had flown together in visual meteorological conditions while maneuvering through cloud layers, but he had never flown into clouds, and she was not aware of him flying in instrument meteorological conditions. The pilot's wife reported that he was generally in good health, and that he was scheduled for a non-critical medical appointment 2 days after the accident. During the phone call from WMC, he did not mention that he was experiencing any physiological issues. The pilot's wife stated that he had been under a significant amount of stress before the trip, but that at its conclusion, he sounded peaceful, revitalized, and relaxed, and he was ready to come home and get back to work. Regarding his personality, she stated that he was very much an "achiever;" at times could be headstrong; and once he had made up his mind, it was very hard to dissuade him. They had discussed the approaching weather system the day before the flight, and she had suggested he drive back with a friend, but he felt strongly that he should fly. AIRCRAFT INFORMATIONThe airplane was manufactured in 1960 and equipped with a Continental Motors O-470R normally aspirated engine and a two-bladed McCauley constant-speed propeller. The most recent maintenance procedure was an annual inspection, completed on February 20, 2016. At that time, the airframe had accrued 5,467.04 flight hours, and the engine had accrued 364.3 hours since overhaul in 2012. The tachometer indicated 2,462.6 hours at the time of the inspection, and following the accident, it indicated 2,532.5 hours. According to the Cessna 182D owner's manual, when loaded to its maximum gross weight of 2,650 lbs, the airplane had a service ceiling of 19,800 ft and a maximum cruise endurance at 10,000 ft of 7.1 hours at 118 mph. At that altitude and given standard atmospheric conditions, the climb rates at weights of 2,100, 2,400, and 2,650 lbs were 925, 710, and 560 ft per minute, respectively. The airplane was not equipped with an autopilot or a supplemental oxygen system. The pilot's wife stated that the pilot had never experienced symptoms of hypoxia and that all flights were flown below 11,500 ft. The airplane was not equipped for flight into known icing conditions. METEOROLOGICAL INFORMATIONA meteorology report was compiled by an NTSB weather specialist. The following is a summary of the complete report, which is contained in the public docket. Upper Air Charts The National Weather Surface (NWS) Storm Prediction Center constant pressure charts for 1700 depicted mid-level troughs just east and west of the accident site at 700-hPa. Troughs typically act as lifting mechanisms where enhanced lift, gusty winds, fronts, clouds, and precipitation can occur. Troughs and frontal boundaries near mountainous terrain also act to aid in the mixing of low-level air, allowing for the possibility of low-level wind shear, mountain waves, and turbulence. In addition, at 500-hPa, there was a mid-level trough west of the accident site, while at 300-hPa the accident site was located in the exit region of a jet streak, where enhanced lift, clouds, and precipitation can occur. There was a southwest wind around 50 knots at 700-hPa with the wind becoming westerly by 300-hPa. The wind increased to 80 knots by 500-hPa with a wind speed of 70 knots at 300-hPa above the accident site. Surface Observations The two closest official weather stations to the accident site were Lake Tahoe Airport (TVL), South Lake Tahoe, California, located 10 miles east-southeast at an elevation of 6,269 ft, and Minden-Tahoe Airport (MEV), Minden, Nevada, located 22 miles east-northeast at an elevation of 4,731 ft. From 1153 through 1453, observations from TVL indicated 10 miles visibility, wind generally out of the south-southwest at 17 to 21 knots gusting between 28 and 32 knots, and scattered/broken cloud layers. By 1453, clouds were broken at 4,400 ft agl with a ceiling at 7,500 ft agl. A special weather observation was issued at 1545, indicating 4 miles visibility, moderate rain, scattered clouds at 2,700 ft agl, and an overcast ceiling at 3,300 ft agl. At 1553, 1 minute after the accident, TVL reported visibility at 4 miles with moderate rain, scattered clouds at 2,400 ft agl, broken ceiling at 2,900 ft agl, overcast skies at 3,400 ft agl, temperature 8°C, dew point 5°C, and an altimeter setting of 29.87 inches of mercury. MEV reported similar observations throughout the afternoon, with visibilities ranging from 7 to 10 miles, with a brief period of light rain and 3-miles visibility during the 1415 report. At 1555, 3 minutes after the accident, MEV reported 8 miles visibility, few clouds at 3,300 ft agl, broken ceiling at 4,800 ft agl, overcast skies at 5,500 ft agl, temperature 9°C, dew point 6°C, and an altimeter setting of 29.87 inches of mercury. A 1455 observation issued for RNO shortly before the airplane passed over its Class C airspace included wind from 210° at 28 knots gusting to 41 knots, few clouds at 5,500 ft agl, scattered clouds at 7,000 ft agl, broken skies at 8,500, 18,000, and 22,000 ft agl. The closest weather reporting station to the destination airport, was Placerville Airport (PVF), Placerville, California, located at an elevation of 2,585 ft, 20 miles north of Jackson JAQ (elevation 1,694 ft). An observation at 1555 indicated wind from 190° at 13 knots, gusting to 20 knots, broken clouds at 3,400 and 5,000 ft, and an overcast ceiling at 9,000 ft. Sounding The closest official upper air sounding was from Reno, Nevada, located 43 miles northeast of the accident site at an elevation of 4,970 ft. Data derived from the 1700 sounding indicated a freezing level at 10,734 ft, with relatively dry conditions east of the Sierra Nevada mountains and a cloud layer likely near 10,000 ft. The sounding wind profile indicated wind speeds of 45 knots at 9,000 ft, with several layers of clear air turbulence indicated between the surface and 14,000 ft. The analysis of the sounding data also indicated that mountain wave conditions were likely near 10,000 ft with updrafts and downdrafts of about 2,645 ft per minute. Mountain wave conditions were also likely at 14,000 and 20,000 ft. Satellite Data Visible and infrared data from the Geostationary Operational Environmental Satellite number 15 (GOES-15) indicated that cloud cover at the accident site began around 1153 and rapidly increased in coverage from the Nevada and California border westward during the time of the flight. Lenticular cloud formations between Winnemucca and South Lake Tahoe were also observed. Based on infrared imagery and the vertical temperature profile provided by the 1700 Reno sounding, the approximate cloud-top heights over the accident site were 18,500 ft at 1545. The visible and infrared imagery indicated that there was extensive cloud cover across the accident site at the accident time, with cloud cover increasing in coverage and height with time. In addition, the lenticular clouds were likely indicative of the mountain wave conditions near the mountainous terrain. Weather Radar Data The closest NWS Weather Surveillance Radar-1988, Doppler (WSR-88D) was from Reno, Nevada, (KRGX) located 61 miles northeast of the accident site at an elevation of 8,299 ft. Level II and III radar data for base reflectivity images for the 0.5° elevation scans initiated at 1545, 1548, and 1551 indicated that the airplane flew through 5-30 dBZ base reflectivity values (light to moderate echo intensity) along the route of flight during that period. The precipitation targets moved from southwest to northeast. Due to terrain, the radar signal was likely blocked near the accident site, and it is possible that more precipitation was present in the area than indicated in the images. The weather radar data indicated that the accident flight likely flew through icing and instrument meteorological conditions while above 10,000 ft msl around the accident time. SIGMETs SIGMET November 1 was issued for the accident area before the flight departed and warned of occasional severe turbulence below 15,000 ft msl due to strong low-level winds and mountain wave activity, with strong updrafts and low-level wind shear. AIRMETs AIRMETs Tango, Zulu, and Sierra, valid for
The noninstrument-rated pilot's decision to depart on and continue a flight over mountainous terrain into forecast instrument metrological conditions, icing, and hazardous wind conditions that exceeded the airplanes performance capabilities and resulted in an uncontrolled descent and collision with terrain.
Source: NTSB Aviation Accident Database
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