# NTSB WPR12LA428: Rockwell International 690A, N57112, Ellensburg, WA, September 16, 2012 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: September 16, 2012, 16:00 local (23:00 UTC) - Place: Ellensburg, WA - Coordinates: 47.02639, -120.525001 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=47.0264&lon=-120.5250&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering: Turbulence encounter](https://openairdocs.org/ntsb-events/360) - Highest injury: Minor injuries - Injuries: 1 minor, 2 uninjured - Status: Completed, report September 12, 2013 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 85095 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR12LA428 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/85095/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=85095 - Page: https://openairdocs.org/ntsb/WPR12LA428 ## Probable cause The pilot’s failure to avoid a turbulent smoke column, which resulted in an overstress failure of the left aileron control rod. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Attention/monitoring: monitoring environment](https://openairdocs.org/ntsb-findings/02021545): Personnel issues › Psychological · Pilot (probable cause); cases with it: [Rockwell International 690A, 1 case](https://openairdocs.org/ntsb-findings/02021545/cases.md?model=7630515), [All aircraft, 809 cases](https://openairdocs.org/ntsb-findings/02021545/cases.md) - [Turbulence](https://openairdocs.org/ntsb-findings/03032000): Environmental issues › Conditions/weather/phenomena · Effect on operation; cases with it: [Rockwell International 690A, 1 case](https://openairdocs.org/ntsb-findings/03032000/cases.md?model=7630515), [All aircraft, 92 cases](https://openairdocs.org/ntsb-findings/03032000/cases.md) - [Flight control system: aileron control system](https://openairdocs.org/ntsb-findings/01022710): Aircraft › Aircraft systems · Capability exceeded (probable cause); cases with it: [Rockwell International 690A, 1 case](https://openairdocs.org/ntsb-findings/01022710/cases.md?model=7630515), [All aircraft, 45 cases](https://openairdocs.org/ntsb-findings/01022710/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering: Turbulence encounter](https://openairdocs.org/ntsb-events/360) (defining event); cases with it: [Rockwell International 690A, 1 case](https://openairdocs.org/ntsb-events/360/sequence.md?model=7630515), [All aircraft, 423 cases](https://openairdocs.org/ntsb-events/360/sequence.md) ## Analysis The pilot reported that, while in a right turn at 7,500 feet mean sea level and above a land wildfire, the airplane entered a turbulent, dark, narrow, column of smoke. The pilot leveled the wings and continued flight through the turbulent column. When the airplane exited the column, the pilot noticed that he had to make a significant right flight control input to maintain level flight. He made a precautionary landing without further incident. Postaccident examination of the airplane revealed that the left aileron control rod was separated along the threaded portion of the shaft, about 2.5 inches from the rod end. Subsequent examination of both pieces of the aileron control rod revealed fracture surfaces consistent with overstress, with no indications of previous wear, fatigue, or corrosion. Thus, it is likely that the turbulence encountered while flying through the smoke column was sufficient to overstress the left aileron control rod. ## Factual narrative On September 16, 2012, about 1600 Pacific daylight time, an Aero Commander 690A, N57112, encountered turbulence and an aileron control system failure while maneuvering above a wild land fire near Ellensburg, Washington (ELN). The airline transport pilot (ATP) sustained minor injuries, and the two passengers sustained no injuries. A precautionary landing was made at ELN after the turbulence encounter. The airplane was registered to Skystar, Inc., and operated by Courtney Aviation under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and a company flight plan was filed for the local flight that departed ELN at 1545. The pilot reported that while in a right turn around a wild land fire at 7,500 feet the airplane circled into a dark, narrow, ascending smoke column that was turbulent. The pilot quickly leveled the wings and continued to fly through the turbulent smoke column. After exiting the smoke column, the pilot noticed that the flight controls had a significant deflection to the right to keep the airplane’s wings level. The pilot elected to make a precautionary landing at ELN. After landing, the airplane was inspected, and the left aileron control rod was found separated along the threaded portion of the shaft, about 2.5 inches from the rod end. The two portions of the aileron control rod were removed from the airplane and shipped to the National Transportation Safety Board Materials Laboratory for further examination. The examination revealed no apparent wear marks along the shaft of the rod; the rod ends exhibited dirt and similar contamination. The fracture surfaces of the control rod were rough with a dull, clean luster, which was indicative of overstress. The fracture surfaces displayed no indications of fatigue or corrosion. ## Aircraft - Registration: [N57112](https://openairdocs.org/aircraft/N57112), registered now, S/N 11263, built 1975 (OpenAirDocs) - Reported make and model: ROCKWELL INTERNATIONAL 690A - Registry model: [Rockwell International 690A](https://openairdocs.org/model/rockwell-international-690a) (registry code 7630515) (OpenAirDocs) - Registry engine: [AiResearch TPE331-5&6SER](https://openairdocs.org/engine/airesearch-tpe331-5-6ser) (registry code 01515, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: 11263 - Airframe hours: 5462 - Engines: Garrett TPE 331-5 715 horsepower turbo prop; Garrett TPE 331-5 715 horsepower turbo prop - Damage: Substantial damage - Flight: Aerial observation, Part 91 - Operator: Courtney Aviation - Registered owner: Skystar Inc - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, September 4, 2012, 15 hours before - Departed: ELN, Ellensburg, WA - Destination: ELN, Ellensburg, WA - Flight plan: Company VFR - Airport: ELN, Bowers Field Airport ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 56; injuries: minor; airline transport, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review May 18, 2012; seat: left; flight hours: 24,000 total, 300 in this make and model, 19,000 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 70° at 3 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 82 °F, dew point 36 °F - Altimeter: 30.12 inHg - Observed at: ELN, 15 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 20120916019709A](https://openairdocs.org/incident/20120916019709A), Sep 16, 2012: Rockwell International 690A, Rimerock, WA, Minor damage. The pilot flew through a column of smoke from a forest fire that he was working for the U.S. Forest service. He encountered several severe bumps of turbulence.… ## Docket (4 files) The files NTSB released with the investigation on June 14, 2013, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=85095. 1.6 MB in all. - Materials Laboratory 15 - Factual Report of Group Chairman (2 Embedded Images) (item 1, .PDF, 2 photos, 637 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40379622&FileExtension=.PDF&FileName=Materials%20Laboratory%2015%20-%20Factual%20Report%20of%20Group%20Chairman%20(2%20Embedded%20Images)-Master.PDF - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 2, .PDF, 588 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40389301&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Weather Reports and Records (item 3, .PDF, 13 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40389302&FileExtension=.PDF&FileName=Weather%20Reports%20and%20Records-Master.PDF - Evidence Control Form (item 4, .PDF, 380 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40393481&FileExtension=.PDF&FileName=Evidence%20Control%20Form-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.