# NTSB ANC21LA043: Cessna 182K, N2761Q, Cordova, AK, May 29, 2021 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 3 · Limited · Final report - Date: May 29, 2021, 13:12 local (21:12 UTC) - Place: Cordova, AK - Coordinates: 60.702468, -143.5103 - Nearby events: https://openairdocs.org/map.md?lat=60.7025&lon=-143.5103&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Windshear or thunderstorm](https://openairdocs.org/ntsb-events/390) - Highest injury: Minor injuries - Injuries: 2 minor - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Alaska Regional Office - Parties: FAA - NTSB case key (mKey): 103184 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC21LA043 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/103184/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=103184 - Page: https://openairdocs.org/ntsb/ANC21LA043 ## Probable cause An encounter with mountain wave turbulence and windshear that exceeded the climb capability of the airplane and resulted in impact with terrain. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Turbulence: terrain induced turbulence](https://openairdocs.org/ntsb-findings/03032010): Environmental issues › Conditions/weather/phenomena · Effect on equipment (probable cause); cases with it: [Cessna 182K, 1 case](https://openairdocs.org/ntsb-findings/03032010/cases.md?model=2072724), [All aircraft, 70 cases](https://openairdocs.org/ntsb-findings/03032010/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Windshear or thunderstorm](https://openairdocs.org/ntsb-events/390) (defining event); cases with it: [Cessna 182K, 1 case](https://openairdocs.org/ntsb-events/390/sequence.md?model=2072724), [All aircraft, 224 cases](https://openairdocs.org/ntsb-events/390/sequence.md) - [Enroute-cruise: Turbulence encounter](https://openairdocs.org/ntsb-events/360); cases with it: [Cessna 182K, 1 case](https://openairdocs.org/ntsb-events/360/sequence.md?model=2072724), [All aircraft, 423 cases](https://openairdocs.org/ntsb-events/360/sequence.md) ## Analysis The pilot reported that, before departure, he reviewed weather conditions and proposed destination locations, which included winds aloft and METARs. About 2 hours and 15 minutes into the flight, at an altitude of about 12,500 mean sea level (msl), the airplane encountered severe turbulence and windshear, and, shortly thereafter, a downdraft. Unable to escape the downdraft, the pilot attempted to level the wings and pitched up. The airplane impacted mountainous terrain, resulting in substantial damage to the fuselage, wings, left horizontal stabilizer, and elevator. The pilot reported no preaccident mechanical failures or malfunctions that would have precluded normal operation. Review of weather information revealed a relatively strong pressure gradient in the area. Upper air soundings indicated favorable conditions for severe mountain wave conditions with updraft and downdraft speeds between 2,000 and 3,000 ft per minute. Based on the available information, it is likely that the flight encountered mountain wave conditions, including severe turbulence, windshear, and downdrafts greater than 2,000 ft per minute, which exceeded the climb capability of the airplane and resulted in descent into terrain. ## Factual narrative On May 29, 2021, about 1312 Alaska daylight time (AKDT), a Cessna 182K, N2761Q, sustained substantial damage when it was involved in an accident about 77 miles east of Cordova, Alaska. The commercial pilot and passenger sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot stated that, after completing a preflight inspection and reviewing weather conditions for the departure and proposed destination locations, which included winds aloft and METARs, they departed on the cross-country flight. About 2 hours and 15 minutes into the flight, while at an altitude of about 12,500 ft mean sea level (msl), the airplane encountered severe turbulence and windshear, and shortly thereafter, a downdraft. Unable to escape the downdraft, the pilot attempted to level the wings and pitched up as the airplane impacted terrain. The pilot reported no preaccident mechanical failures or malfunctions that would have precluded normal operations. The airplane impacted snow- and ice-covered terrain on the north side of Mount Hawkins in the Wrangell St Elias National Park at an elevation of about 6,570 ft msl. During the impact, the airplane sustained substantial damage to the fuselage, wings, left horizontal stabilizer and elevator. A review of flight track data revealed that, after departure, the flight proceeded to the south and climbed to an altitude of about 11,000 ft msl before initiating a left turn to the east. The flight continued on an easterly heading at an altitude between about 11,000 and 12,900 ft msl. The last in-flight data point was at 1311:19, when the airplane was at an altitude of 11,800 ft msl with a groundspeed of 108 kts and on a track of 117°. (see figures 1 and 2.) Figure 1 - Flight track. Figure 2 - Flight track, end of flight. No frontal boundaries existed near the accident site; however, a relatively strong pressure gradient was present along the northern Gulf of Alaska. The National Weather Service, Anchorage, Alaska, upper air soundings from 0400 and 1600 both indicated favorable conditions for severe mountain wave conditions between 9,000 and 14,000 ft mean sea level with updraft and downdraft speeds between 2,000 and 3,000 ft per minute. These conditions would be prevalent near any mountains with tops between 5,000 and 13,000 ft msl; the mountains to the south of the accident site were between this height. The Polar Operational Environmental Satellites imagery from 1337 also showed transverse wave banding at the accident site, which is indicative of mountain waves. FAA Advisory Circular (AC) 00-6B, Aviation Weather, describes mountain wave conditions and the associated aviation hazards therein: A mountain wave is an atmospheric wave disturbance formed when stable air flow passes over a mountain or mountain ridge. Mountain waves are a form of mechanical turbulence which develop above and downwind of mountains. The waves remain nearly stationary while the wind blowsrapidly through them. The waves may extend 600 miles (1,000 kilometers) or more downwind from the mountain range. Mountain waves frequently produce severe to extreme turbulence. Location and intensity varies with wave characteristics. Figure 3 - AC 00-06B mountain wave conditions. Mountain waves often produce violent downdrafts on the immediate leeward side of the mountain barrier. Sometimes the downward speed exceeds the maximum climb rate of an aircraft and may drive the aircraft into the mountainside. ## Aircraft - Registration: [N2761Q](https://openairdocs.org/deregistered/N2761Q-2022-11-05), registration cancelled 2022-11-05, S/N 18257961, built 1967 (OpenAirDocs) - Reported make and model: CESSNA 182K (K) - Registry model: [Cessna 182K](https://openairdocs.org/model/cessna-182k) (registry code 2072724) (OpenAirDocs) - Registry engine: [Continental O-470 series](https://openairdocs.org/engine/continental-o-470-series) (registry code 17026, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 18257961 - Year built: 1967 - Airframe hours: 2938 - Engines: CONT MOTOR O-470 SERIES 230 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Dataworks Of New York Inc - Airworthiness certificate: Standard, Normal - Last inspection: Annual, July 1, 2020 - Departed: Talkeetna, AK - Destination: Yakutat, AK - Equipment: Onboard weather, Electronic flight bag or handheld device, Auto-pilot, ADS-B, Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 59; injuries: minor; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; last flight review November 16, 2019; seat: left; restraint: lap only; flight hours: 838 total, 788 in this make and model, 783 as pilot in command, 72 in the last 90 days, 42 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Instrument (IMC), Day - Wind: 100° at 6 knots - Visibility: 8 statute miles - Lowest ceiling: 5,000 ft overcast - Temperature: 48 °F, dew point 43 °F - Altimeter: 29.70 inHg - Observed at: PACV, 59 nm away - METAR: PACV 292053Z 10006KT 8SM -RA OVC050 09/06 A2970 RMK AO2 SLP058 P0003 60013 T00890061 51008 ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20210529009409A](https://openairdocs.org/incident/20210529009409A), May 29, 2021: Cessna 182K, Yakutat, AK, Destroyed. Aircraft took off from talkeetna towards Yakutat, climbing to 12,500 and VFR on top over a cloud layer, through the coastal mountain range area. Aircraft was… ## Docket (10 files) The files NTSB released with the investigation on June 2, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=103184. 126 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 11.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12450011&FileExtension=pdf&FileName=NTSB%206120_1_Redacted-Rel.pdf - Weather factual report (item 2, PDF, 35 pages, 2.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12812062&FileExtension=pdf&FileName=ANC21LA043_weatherfactualSuffernfinal-Rel.pdf - Weather - attachment 1 (item 3, GIF, 5.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12811594&FileExtension=gif&FileName=attachmen1_animationSAT_VIS_2000to2200utc_CODNEXLAB-GOES-West-regional-GulfOfAK-02-22_00Z-20210529_latlon-map_-8-1n-10-100-Rel.gif - Weather - attachment 2 (item 4, ZIP, 99.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12811172&FileExtension=zip&FileName=attachment2_polarsatellitedata-Rel.zip - Weather - attachment 3 (item 5, PDF, 1 page, 781 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12812072&FileExtension=pdf&FileName=attachment3_crossectionquickguide-Rel.pdf - Weather - attachment 4 (item 6, ZIP, 3.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12811604&FileExtension=zip&FileName=attachment4_AAWUgraphics-Rel.zip - Weather - attachment 5 (item 7, ZIP, 2.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12811393&FileExtension=zip&FileName=attachment5_GTGstuff-Rel.zip - Witness statements (item 8, PDF, 40 pages, 186 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12818310&FileExtension=pdf&FileName=ANC21LA043_Interview%20Transcripts_Redacted-Rel.pdf - Opsvue track data (item 9, CSV, 46 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12856146&FileExtension=csv&FileName=N2716Q%20Departure-Rel.csv - Photos (item 10, PDF, 2 pages, 750 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12450334&FileExtension=pdf&FileName=Photo%20array-Rel.pdf From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.