# NTSB WPR11TA087: Piper PA-18-180, N6774B, Shoshoni, WY, January 2, 2011 - Type: NTSB accident investigation - Classification: Accident · No injuries · Final report - Date: January 2, 2011, 13:15 local (20:15 UTC) - Place: Shoshoni, WY - Coordinates: 43.159168, -107.937774 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.1592&lon=-107.9378&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report November 22, 2011 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: United States Department of Agriculture - NTSB case key (mKey): 78110 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR11TA087 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/78110/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=78110 - Page: https://openairdocs.org/ntsb/WPR11TA087 ## Probable cause A total loss of engine power for undetermined reasons. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Terrain: sloped/uneven terrain](https://openairdocs.org/ntsb-findings/03021017): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Piper PA-18-150, 10 cases](https://openairdocs.org/ntsb-findings/03021017/cases.md?model=7101828), [All aircraft, 270 cases](https://openairdocs.org/ntsb-findings/03021017/cases.md) - [Terrain: rough terrain](https://openairdocs.org/ntsb-findings/03021015): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Piper PA-18-150, 19 cases](https://openairdocs.org/ntsb-findings/03021015/cases.md?model=7101828), [All aircraft, 442 cases](https://openairdocs.org/ntsb-findings/03021015/cases.md) - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Piper PA-18-150, 9 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=7101828), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Piper PA-18-150, 18 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=7101828), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Landing-landing roll: Landing gear collapse](https://openairdocs.org/ntsb-events/094); cases with it: [Piper PA-18-150, 16 cases](https://openairdocs.org/ntsb-events/094/sequence.md?model=7101828), [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis According to the pilot, during a wildlife aerial observation flight, the engine suddenly stopped producing power. The pilot checked the fuel selector and magnetos and applied carburetor heat. Because he was unable to get the engine started again, he executed a forced landing on rough/uneven terrain. During the landing roll, the airplane went off a low bank, contacted the terrain at the bottom of the bank, and sustained substantial damage. At the time of the accident, the airplane had about one hour of fuel remaining, and the postaccident inspection, which included a successful engine run, did not find any anomalies that would have contributed to a loss of power. The ambient temperature and dew point were outside of the range at which carburetor icing would be expected to occur. ## Factual narrative On January 2, 2011, about 1315 mountain standard time, a Piper PA-18-180, N6774B, experienced a gear collapse during a forced landing about 10 miles southeast of Shoshoni, Wyoming. The commercial pilot and his passenger were not injured, but the airplane, which was owned by STP Aviation LLP, and operated by the United States Department of Agriculture, sustained substantial damage. The local Public Use wildlife aerial observation flight, which departed Riverton Municipal Airport, Riverton, Wyoming, about four hours prior to the accident, was being operated in visual meteorological conditions. No flight plan had been filed. According to the pilot, during the aerial observation flight, the engine suddenly stopped producing power. He therefore checked the fuel selector, applied carburetor heat, made sure the magneto switch was on both, and tried to restart the engine. Because the engine did not restart, he made the decision to make a forced landing on the rough, brush-covered terrain. Although the touchdown was successful, during the landing roll, the airplane went off a low bank, and upon contacting the terrain at the bottom of the bank, the main landing gear support structure failed allowing both gear struts to fold outward. During the accident sequence, the left wing lift strut was bent to the extent that it had to be replaced. A postaccident examination of the airplane's fuel system determined that it had more than one hour of fuel remaining (10+ gallons). As part of the examination process, the engine was test run for several minutes with no sign of any anomaly. The investigation also determined that the ambient temperature and dew point (temperature of ten degrees F/dew point of one degree F) were outside the range at which carburetor icing would be expected in maneuvering flight. At the end of the investigation, no other fuel system or engine anomalies had been found, and the reason for the loss of engine power was not able to be determined. ## Aircraft - Registration: [N6774B](https://openairdocs.org/aircraft/N6774B), registered now, S/N 18-5007, built 1956 (OpenAirDocs) - Reported make and model: PIPER PA-18-180 - Registry model: [Piper PA-18-150](https://openairdocs.org/model/piper-pa-18-150) (registry code 7101828) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 18-5007 - Airframe hours: 2565 - Engines: Lycoming O-360-C4P 180 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial observation, Public use - Operator: United States Department Agriculture - Registered owner: T and T Aviation - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, August 11, 2010 - Departed: KRIW, Riverton, WY - Destination: KRIW, Riverton, WY ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 53; injuries: none; commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; last flight review February 15, 2010; seat: front; flight hours: 10,500 total, 10,200 in this make and model, 10,500 as pilot in command, 150 in the last 90 days, 50 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 10 °F, dew point 1 °F - Altimeter: 29.90 inHg - Observed at: KRIW, 30 nm away ## 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 20110102000139A](https://openairdocs.org/incident/20110102000139A), Jan 2, 2011: Piper PA-18-150, Shoshoni, WY, Substantial damage. At about 200 feet AGL the engine quit. An emergency landing in difficult snow covered terrain was made resulting in substantial damage. ## Other investigations on N6774B (1) 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. - [NTSB NYC06CA217](https://openairdocs.org/ntsb/NYC06CA217), Aug 31, 2006: Piper PA-18-150 (N6774B), White Lake, NY, substantial damage. Probable cause: The flight instructor's failure to ensure the landing gear was retracted prior to attempting a water landing. ## Docket (3 files) The files NTSB released with the investigation on October 7, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=78110. 562 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 490 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40354876&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Record of Conversation (item 2, .PDF, 50 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40354875&FileExtension=.PDF&FileName=Record%20of%20Conversation-Master.PDF - Engine Run Report (item 3, .PDF, 22 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40354877&FileExtension=.PDF&FileName=Engine%20Run%20Report-Redacted.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.