# NTSB CEN15LA403: Cessna 182, Big Piney, WY, August 16, 2015 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: August 16, 2015, 10:30 local (16:30 UTC) - Place: Big Piney, WY - Coordinates: 43.159721, -109.658889 - Nearby events: https://openairdocs.org/map.md?lat=43.1597&lon=-109.6589&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) - Highest injury: Minor injuries - Injuries: 2 minor - Status: Completed, report June 25, 2019 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA FSFO - NTSB case key (mKey): 91947 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN15LA403 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/91947/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=91947 - Page: https://openairdocs.org/ntsb/CEN15LA403 ## Probable cause The pilot's failure to maintain adequate altitude while operating over high mountainous terrain, which resulted in an emergency landing after the airplane's encounter with a downdraft. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Use of equip/info](https://openairdocs.org/ntsb-findings/02063000): Personnel issues › Task performance · Pilot (probable cause); cases with it: [All aircraft, 111 cases](https://openairdocs.org/ntsb-findings/02063000/cases.md) - [Performance/control parameters: altitude](https://openairdocs.org/ntsb-findings/01062012): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [All aircraft, 1,310 cases](https://openairdocs.org/ntsb-findings/01062012/cases.md) - [Terrain](https://openairdocs.org/ntsb-findings/03021000): Environmental issues › Physical environment · Contributed to outcome (probable cause); cases with it: [All aircraft, 267 cases](https://openairdocs.org/ntsb-findings/03021000/cases.md) - [Turbulence: terrain induced turbulence](https://openairdocs.org/ntsb-findings/03032010): Environmental issues › Conditions/weather/phenomena · Contributed to outcome (probable cause); cases with it: [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. - [Maneuvering: Other weather encounter](https://openairdocs.org/ntsb-events/400); cases with it: [All aircraft, 1,127 cases](https://openairdocs.org/ntsb-events/400/sequence.md) - [Maneuvering: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) (defining event); cases with it: [All aircraft, 780 cases](https://openairdocs.org/ntsb-events/220/sequence.md) - [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) ## Analysis The private pilot reported that, during a preflight briefing, he and the pilot-rated passenger (who was the owner of the airplane) agreed that in the case of an emergency, the owner would take control of the airplane. After takeoff, the sightseeing flight was normal until the airplane approached a glacier at 12,000 ft mean sea level. The pilot stated that because the airplane engine was normally aspirated, there was not much power left to climb, but everything was "ok." As the airplane entered the glacier area through a canyon, it encountered a sudden downdraft and started to descend; the pilot recalled that the airplane's altitude above terrain was about 500 ft. The pilot tried to maintain a level attitude, but the airspeed began to decrease as the airplane continued to descend. The pilot-rated passenger then took control of the airplane and immediately lowered the nose to increase airspeed and set up for an emergency landing; the airplane appeared to be stalling. The airplane landed hard on ice ditches, separating the nose gear. The main landing gear dug in and the airplane came to a stop, which resulted in structural damage to the fuselage. No mechanical malfunctions or failures were reported by the pilot. Because the engine was normally aspirated, the performance of the engine was reduced at a high altitude. Further, the airplane was about 500 ft above terrain when the downdraft occurred. Considering that downdrafts in high mountainous terrain can exceed 1,000 ft per minute, the pilot did not maintain adequate altitude for the operating environment. ## Factual narrative On August 16, 2015 about 0930 mountain daylight time, a Cessna 182, XBYUH (Mexican Registry), impacted high mountainous terrain during a forced landing about 37 miles out from the Big Piney, Wyoming VOR (BPI) 015 Degree Radial. Both occupants, the pilot and pilot-rated passenger, sustained minor injuries. The flight was being conducted under the provisions of Federal Code of Regulations Part 91. Visual meteorological conditions prevailed throughout the vicinity and a flight plan was not filed. The local flight originated from the Alpine Municipal Airport (46U) about 0800. The pilot reported that the purpose of the flight was sightseeing. During a preflight briefing, the pilot-rated passenger (who was the owner of the airplane), and the pilot agreed that in the case of an emergency, the owner would take control of the airplane. After takeoff from 46U, the flight was normal until approaching a glacier at 12,000 feet MSL. The pilot stated that because the airplane engine was normally aspirated, there was not much power left to climb, but everything was "OK." As the airplane entered the glacier through a canyon, a sudden downdraft caught the airplane and the airplane started to descend. The pilot recalls that the altitude above terrain was about 500 feet. The pilot tried to maintain a level attitude and the airspeed began to decrease as the airplane continued to descend. The owner then took control of the airplane. He immediately lowered the nose to increase airspeed. Since the airplane was still descending, he asked for flaps and announced that he would execute an emergency landing. The airplane appeared to be stalling. The airplane landed hard on ice ditches, ripping off the nose gear. The main landing gear dug-in and the airplane came to a stop. Figure 1. Approximate flight path into the glacier forced landing area. An American Airlines commercial flight picked up a mayday call and relayed the information to Salt Lake City Air Traffic Control. The wreckage was located by mountain rescue personnel and the two occupants were transported to a local hospital. No mechanical anomalies were reported by the pilot or owner. According to the FAA, downdrafts in high mountainous terrain can exceed 1,000 feet per minute and a normally aspirated engine's horsepower and performance is reduced at high altitudes. ## Aircraft - Registration: XBYUH (not matched to a registry record) - Reported make and model: CESSNA 182 (P) - Category: Airplane - Serial number: 182633285 - Airframe hours: 3093 - Engines: Continental O-470R 230 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, August 11, 2015 - Departed: 46U, Alpine, CO - Destination: 46U, Alpine, CO - Equipment: Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 58; injuries: minor; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, without waivers/limitations; seat: left; restraint: 4-point; flight hours: 1,904 total, 454 in this make and model, 25 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 260° at 14 knots, gusting 25 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 61 °F, dew point 50 °F - Altimeter: 30.30 inHg - Observed at: 46U ## Docket (3 files) The files NTSB released with the investigation on April 9, 2019, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=91947. 3.7 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40471792&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Photo Array (item 2, .PDF, 4 photos, 834 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40471793&FileExtension=.PDF&FileName=Photo%20Array-Master.PDF - FAA Enhancement Topic Mountain Flying (item 3, .PDF, 1.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40471794&FileExtension=.PDF&FileName=FAA%20Enhancement%20Topic%20Mountain%20Flying-Master.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.