# NTSB ANC11CA021: Piper PA-18-150, N91117, Chicken Lake, AK, March 27, 2011 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: March 27, 2011, 14:00 local (22:00 UTC) - Place: Chicken Lake, AK - Coordinates: 61.63861, -150.100006 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=61.6386&lon=-150.1000&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report June 20, 2011 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: FAA - NTSB case key (mKey): 78700 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC11CA021 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/78700/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=78700 - Page: https://openairdocs.org/ntsb/ANC11CA021 ## Probable cause The pilot's failure to maintain adequate clearance from terrain. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: altitude](https://openairdocs.org/ntsb-findings/01062012): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Piper PA-18-150, 7 cases](https://openairdocs.org/ntsb-findings/01062012/cases.md?model=7101828), [All aircraft, 1,310 cases](https://openairdocs.org/ntsb-findings/01062012/cases.md) - [Action: incorrect action performance](https://openairdocs.org/ntsb-findings/02041015): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Piper PA-18-150, 12 cases](https://openairdocs.org/ntsb-findings/02041015/cases.md?model=7101828), [All aircraft, 1,386 cases](https://openairdocs.org/ntsb-findings/02041015/cases.md) - [Light condition: flat light](https://openairdocs.org/ntsb-findings/03036025): Environmental issues › Conditions/weather/phenomena · Contributed to outcome; cases with it: [Piper PA-18-150, 2 cases](https://openairdocs.org/ntsb-findings/03036025/cases.md?model=7101828), [All aircraft, 42 cases](https://openairdocs.org/ntsb-findings/03036025/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) (defining event); cases with it: [Piper PA-18-150, 5 cases](https://openairdocs.org/ntsb-events/220/sequence.md?model=7101828), [All aircraft, 780 cases](https://openairdocs.org/ntsb-events/220/sequence.md) - [Maneuvering-low-alt flying: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Piper PA-18-150, 115 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=7101828), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot stated that during a low level reconnaissance pass of a frozen, snow-covered lake, the airplane inadvertently contacted the snow in flat light conditions, and nosed over. The airplane sustained substantial damage to the right wing. ## Factual narrative The pilot stated that, during a low level reconnaissance pass of a frozen, snow-covered lake, he inadvertently contacted the snow in flat light conditions, and the airplane nosed over. The airplane sustained substantial damage to the right wing. ## Aircraft - Registration: [N91117](https://openairdocs.org/aircraft/N91117), registered now, S/N 18-8109072, built 1981 (OpenAirDocs) - Reported make and model: PIPER PA-18-150 - 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: 18-8109072 - Engines: LYCOMING O-320 SERIES 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Eberle Terrence F - Registered owner: Eberle Terrence F - Airworthiness certificate: Standard, Utility; Standard, Normal - Departed: PAMR, Anchorage, AK - Destination: Chicken Lake, AK - Flight plan: Unknown ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 26; injuries: none; flight instructor, commercial; airplane ratings: single-engine sea, single-engine land; instrument ratings: helicopter; medical: class 2, with waivers/limitations; seat: front; flight hours: 1,517 total, 16 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 140° at 4 knots - Visibility: 10 statute miles - Lowest ceiling: 3,700 ft broken - Temperature: 32 °F, dew point 21 °F - Altimeter: 29.54 inHg - Observed at: PAWS, 16 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 20110327005509A](https://openairdocs.org/incident/20110327005509A), Mar 27, 2011: Piper PA-18-150, Big Lake, AK, Substantial damage. Coventional gear tundra tire equipped aircraft nosed over after contact with deep snow. Pilot was conducting a low approach for survey of proposed landing area… ## Other investigations on N91117 (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 ANC90LA066](https://openairdocs.org/ntsb/ANC90LA066), May 5, 1990: Piper PA-18 (N91117), Glennallen, AK, substantial damage. Probable cause: THE PILOT FAILED TO MAINTAIN PROPER ALTITUDE AND TERRAIN CLEARANCE WHILE MANEUVERING. ## Docket (1 files) The files NTSB released with the investigation on May 6, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=78700. 561 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 561 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40347327&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-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.