# NTSB ANC11CA058: Aviat A-1B, N949AK, Palmer, AK, July 6, 2011 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Data collection · Final report - Date: July 6, 2011, 09:48 local (17:48 UTC) - Place: Palmer, AK - Coordinates: 61.484165, -149.041946 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=61.4842&lon=-149.0419&mi=10 - Phase of flight: [Uncontrolled descent](https://openairdocs.org/ntsb-phases/650) (OpenAirDocs' grouping) - Defining event: [Uncontrolled descent: Turbulence encounter](https://openairdocs.org/ntsb-events/360) - Highest injury: Serious injuries - Injuries: 1 serious, 1 minor - Status: Completed, report October 6, 2011 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: Federal Aviation Administration - NTSB case key (mKey): 81043 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC11CA058 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/81043/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=81043 - Page: https://openairdocs.org/ntsb/ANC11CA058 ## Probable cause The pilot's decision to fly at a low altitude in mountainous terrain and weather conditions conducive to downdrafts. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Wind: downdraft](https://openairdocs.org/ntsb-findings/03034035): Environmental issues › Conditions/weather/phenomena · Contributed to outcome; cases with it: [Aviat A-1B, 4 cases](https://openairdocs.org/ntsb-findings/03034035/cases.md?model=2210406), [All aircraft, 178 cases](https://openairdocs.org/ntsb-findings/03034035/cases.md) - [Turbulence: terrain induced turbulence](https://openairdocs.org/ntsb-findings/03032010): Environmental issues › Conditions/weather/phenomena · Contributed to outcome; cases with it: [Aviat A-1B, 1 case](https://openairdocs.org/ntsb-findings/03032010/cases.md?model=2210406), [All aircraft, 70 cases](https://openairdocs.org/ntsb-findings/03032010/cases.md) - [Aircraft capability: climb capability](https://openairdocs.org/ntsb-findings/01061010): Aircraft › Aircraft oper/perf/capability · Capability exceeded; cases with it: [Aviat A-1B, 1 case](https://openairdocs.org/ntsb-findings/01061010/cases.md?model=2210406), [All aircraft, 183 cases](https://openairdocs.org/ntsb-findings/01061010/cases.md) - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Aviat A-1B, 9 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=2210406), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/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: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Aviat A-1B, 23 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2210406), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) - [Uncontrolled descent: Turbulence encounter](https://openairdocs.org/ntsb-events/360) (defining event); cases with it: [Aviat A-1B, 1 case](https://openairdocs.org/ntsb-events/360/sequence.md?model=2210406), [All aircraft, 423 cases](https://openairdocs.org/ntsb-events/360/sequence.md) ## Analysis The pilot reported that he was flying at a low altitude in mountainous terrain when the airplane encountered a strong downdraft, and began to descend. He added full engine power to stop the descent, but the airplane continued to descend, and impacted an area of down sloping, rock-covered terrain. The airplane sustained substantial damage to the fuselage, wings, and empennage. The pilot indicated that there were no preaccident mechanical problems with the airplane. ## Factual narrative The pilot reported that he was flying in mountainous terrain while showing the passenger some sheep. As the airplane passed near an area of steep terrain, he encountered a strong downdraft, and the airplane began to descend. He added full engine power to stop the descent, but the airplane continued to descend, and impacted an area of down sloping, rock-covered terrain. The airplane sustained substantial damage to the fuselage, wings, and empennage. The pilot indicated that there were no preaccident mechanical problems with the airplane. ## Aircraft - Registration: [N949AK](https://openairdocs.org/deregistered/N949AK-2015-05-18), registration cancelled 2015-05-18, S/N 2444, built 2009 (OpenAirDocs) - Reported make and model: AVIAT AIRCRAFT INC A-1B - Registry model: [Aviat A-1B](https://openairdocs.org/model/aviat-a-1b) (registry code 2210406) (OpenAirDocs) - Registry engine: [Lycoming O-360-A1P](https://openairdocs.org/engine/lycoming-o-360-a1p) (registry code 42259, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 2444 - Engines: LYCOMING O-360-A1P 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Cline Richard L - Registered owner: Cline Richard L - Airworthiness certificate: Standard, Normal - Departed: OAK1, Palmer, AK - Destination: OAK1, Palmer, AK ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 60; injuries: minor; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; seat: front; flight hours: 11,800 total, 600 in this make and model, 10,000 as pilot in command, 122 in the last 90 days, 1 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Visibility: 50 statute miles - Lowest ceiling: none ## 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 20110706014029A](https://openairdocs.org/incident/20110706014029A), Jul 6, 2011: Aviat Aircraft Inc A-1B, Palmer, AK, Destroyed. Pilot [privacy data omitted] with one passenger on a sightseeing flight from strip at anderson lake AK.(OAK1). While flying along the face of pioneer peak,… ## Docket (1 files) The files NTSB released with the investigation on August 10, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=81043. 507 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 507 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40352223&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.