# NTSB MIA08LA133: Rockwell International S-2R, N8499V, Colquitt, GA, July 5, 2008 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: July 5, 2008, 11:30 local (15:30 UTC) - Place: Colquitt, GA - Coordinates: 31.195833, -84.684448 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=31.1958&lon=-84.6844&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report March 23, 2010 - Report: Approved by Office Director - Parties: FAA/FSDO, Pratt & Whitney - NTSB case key (mKey): 68365 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MIA08LA133 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/68365/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=68365 - Page: https://openairdocs.org/ntsb/MIA08LA133 ## Probable cause Loss of engine power due to the installation of incorrect turbine blades on the compressor turbine disk during repair of the disk assembly. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Maintenance: repair](https://openairdocs.org/ntsb-findings/02062015): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Rockwell International S-2R, 1 case](https://openairdocs.org/ntsb-findings/02062015/cases.md?model=7630202), [All aircraft, 99 cases](https://openairdocs.org/ntsb-findings/02062015/cases.md) - [Engine (turbine/turboprop): compressor section](https://openairdocs.org/ntsb-findings/01057230): Aircraft › Aircraft power plant · Incorrect service/maintenance (probable cause); cases with it: [Rockwell International S-2R, 1 case](https://openairdocs.org/ntsb-findings/01057230/cases.md?model=7630202), [All aircraft, 53 cases](https://openairdocs.org/ntsb-findings/01057230/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Rockwell International S-2R, 7 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=7630202), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Maneuvering: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Rockwell International S-2R, 8 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=7630202), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-flare/touchdown: Hard landing](https://openairdocs.org/ntsb-events/092); cases with it: [Rockwell International S-2R, 2 cases](https://openairdocs.org/ntsb-events/092/sequence.md?model=7630202), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md) ## Analysis Shortly after takeoff during an agricultural application flight, approximately 834 hours since the turbine blades were installed, the engine experienced a loss of power resulting in a forced landing. Unable to dump his chemical load due to cars on a highway, the pilot executed a forced landing in a field resulting in substantial damage to both wings. Examination of the engine revealed that during repair of the compressor turbine disk in 2005, incorrect part number Federal Aviation Administration (FAA) Parts Manufacturer Approval (PMA) turbine blades were installed in all positions of the compressor turbine disk of the accident engine. The engine was approved for return to service. One of the turbine blades failed due to fatigue causing the remaining blades to fracture due to overstress. ## Factual narrative On July 5, 2008, about 1130 eastern daylight time, a Rockwell S-2R, N8499V, experienced a loss of engine power shortly after takeoff and crashed in a field near Colquitt, Georgia. The commercial certificated pilot received minor injuries and the airplane was substantially damaged. The airplane was operated by Double R Flight Service under the provisions of Title 14 Code of Federal Regulations (CFR) Part 137 as an aerial application flight. Visual meteorological conditions prevailed and no flight plan was filed. The local flight was originating at the time of the accident. The pilot stated to the responding Federal Aviation Administration (FAA) inspector that before takeoff he loaded the aircraft with about 300 gallons of spray solution and topped off the left wing tank; the right tank was half full. During the initial climb at about 300 feet, he noticed a small puff of white smoke exit the exhaust followed by a loss of engine power. At that time, he was over a highway and decided not to jettison his chemical load due to concerns for the safety of people on the ground. The aircraft impacted the ground moments later in a nose and right wing low attitude. The pilot further reported that there was no vibration or shudder associated with the puff of smoke, and he believed the engine went to flight idle and never completely lost power. Examination of the airplane by an FAA inspector revealed that the engine remained partially attached to the airframe, and the wings were substantially damaged. Examination of the Pratt & Whitney Canada PT6A-34AG engine by a representative of the engine manufacturer with FAA oversight revealed the engine displayed moderate impact damage but no fire damage. The compressor turbine shroud was heavily battered, gouged, and circumferentially scored. Inspection of the compressor turbine disk part number (P/N) 301311, serial number (S/N 9963, revealed the blade airfoils were fractured from the root to approximately three quarter span. The upstream side of the blade platforms displayed light circumferential rubbing across approximately one third of the disk circumference due to contact with the compressor turbine guide vane ring. Removal of one of the blades revealed the P/N prefix began with the letter “T.” The disk was retained for further examination. Examination of the compressor turbine disk was performed at the Safety Board’s Materials Laboratory located in Washington, D.C. The results of the examination revealed all inspected turbine blade were marked with P/N T-102401-01. The fracture surface of turbine blade No. 34 exhibited smooth granular pattern. Following removal of the blade from the disk, an area near the trailing edge had a green colored appearance which is consistent with a preexisting crack. The fracture in the green colored area was located 0.15 inch above the blade platform and extended up to approximately 0.25 inch from the trailing edge. Additionally, the fracture surface exhibited areas of transgranular fracture with radial marks and curving arrest lines, features that are consistent with fatigue. The furthest fatigue features observed was approximately 0.32 inch from the trailing edge. Review of the maintenance records revealed the compressor turbine disk was repaired on March 24, 2005. During the repair 58 serviceable turbine blades P/N T102401-01 were installed. The turbine blades were FAA PMA blades manufactured by Turbo Products, Inc. The disk was approved for return to service and installed in the engine. The engine had accumulated approximately 834 hours since the repaired compressor turbine disk was installed. According to the FAA Parts Manufacturer Approval (PMA) list for Turbo Products, Inc., turbine blade P/N T-102401-01 are eligible to be installed in Pratt and Whitney Canada model PT6A-11, 11AG, 15AG, 21, 25, 25A, 27, 28, 110, and 112 series engines. The list indicates that the correct P/N turbine blade for the accident engine, model PT6A-34AG, is P/N T-102401-792. ## Aircraft - Registration: [N8499V](https://openairdocs.org/deregistered/N8499V-2014-11-24), registration cancelled 2014-11-24, S/N 2372R, built 1977 (OpenAirDocs) - Reported make and model: ROCKWELL INTERNATIONAL S-2R - Registry model: [Rockwell International S-2R](https://openairdocs.org/model/rockwell-international-s-2r) (registry code 7630202) (OpenAirDocs) - Registry engine: [Pratt & Whitney R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 2372R - Airframe hours: 14022 - Engines: P&W PT6A-34AG 750 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Double R Flight Service Inc, doing business as Aerial Application - Registered owner: Double R Flight Service Inc - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, May 30, 2008 - Departed: Colquitt, GA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 58; injuries: minor; commercial; airplane ratings: single-engine land; medical: class 2, with waivers/limitations; last flight review July 30, 2006; seat: center; flight hours: 16,305 total, 9,800 in this make and model, 100 in the last 90 days, 40 in the last 30 days, 9 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 190° at 7 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 90 °F, dew point 70 °F - Altimeter: 30.06 inHg - Observed at: ABY ## 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 20080705855249A](https://openairdocs.org/incident/20080705855249A), Jul 5, 2008: Ayres S2R, Colquitt, GA, Substantial damage. (-23) During application of agricultural chemicals (mepex and vidrin), while making west-east run, on pull-up at east end of field to 300', puff of white smoke… ## Docket (8 files) The files NTSB released with the investigation on January 13, 2010, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=68365. 27.5 MB in all. - Materials Laboratory 15 - Factual Report 09-038 (item 1, .PDF, 13.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40314972&FileExtension=.PDF&FileName=Materials%20Laboratory%2015%20-%20Factual%20Report%2009-038-Master.PDF - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 2, .PDF, 741 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323974&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Reports from Parties to the Investigation-Pratt & Whitney (item 3, .PDF, 13.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323971&FileExtension=.PDF&FileName=Reports%20from%20Parties%20to%20the%20Investigation-Pratt%20%26%20Whitney-Redacted.PDF - Excerpt from Maintenance Records (item 4, .PDF, 100 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323975&FileExtension=.PDF&FileName=Excerpt%20from%20Maintenance%20Records-Redacted.PDF - Federal Aviation Administration Parts Manufacturer Approval (PMA) List for Turbo Products, Inc. (item 5, .PDF, 136 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323976&FileExtension=.PDF&FileName=Federal%20Aviation%20Administration%20Parts%20Manufacturer%20Approval%20(PMA)%20List%20for%20Turbo%20Products,%20Inc.-Redacted.PDF - Federal Aviation Administration (FAA) 8130-3 Form Pertaining to Compressor Disk Assembly Repair. (item 6, .PDF, 88 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323977&FileExtension=.PDF&FileName=Federal%20Aviation%20Administration%20(FAA)%208130-3%20Form%20Pertaining%20to%20Compressor%20Disk%20Assembly%20Repair.-Redacted.PDF - Statement of Party Representatives to NTSB Investigation (item 7, .PDF, 67 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323972&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Redacted.PDF - Release of Aircraft Wreckage, NTSB Form 6120.15 (item 8, .PDF, 107 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40323973&FileExtension=.PDF&FileName=Release%20of%20Aircraft%20Wreckage,%20NTSB%20Form%206120.15-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.