# NTSB FTW02LA223: Piper PA-36-285, N57597, Altus, OK, August 2, 2002 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 2, 2002, 12:20 local (17:20 UTC) - Place: Altus, OK - Coordinates: 34.650001, -99.26667 - Nearby events: https://openairdocs.org/map.md?lat=34.6500&lon=-99.2667&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report September 30, 2003 - Report: Approved by Office Director - Parties: Federal Aviation Administartion (FSDO) - NTSB case key (mKey): 55363 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW02LA223 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/55363/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=55363 - Page: https://openairdocs.org/ntsb/FTW02LA223 ## Probable cause The loss of engine power as a result of the fracture of a compressor turbine blade due to fatigue. A contributing factor was the lack of suitable terrain for the forced landing. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power, maneuvering - aerial application - turbine assembly,turbine blade - fatigue (cause) - Forced landing, descent - emergency - In flight collision with terrain/water, emergency landing - terrain condition - none suitable (contributing factor) - terrain condition - ground ## Analysis According to the pilot, he was flying east, executing his final pass in a field when he heard a "loud noise" and the engine lost total power. He looked for a forced landing location, but obstructions/hazards were identified ahead and on both sides of the airplane. He attempted to turn the airplane 180 degrees, but the airplane impacted the ground, slid approximately 200 feet and came to rest upright. The engine examination revealed that compressor turbine blade #22 fractured due to creep and there was heat distress in the combustion liner, and burnt temperature probes. ## Factual narrative On August 2, 2002, at 1220 central daylight time, a Piper PA-36-285 single-engine agricultural airplane, N57597, was substantially damaged during a forced landing following a complete loss of engine power while maneuvering near Altus, Oklahoma. The airplane was registered to and operated by Altus Ag-Air, of Altus. The commercial pilot, sole occupant of the airplane, was not injured. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 137 aerial application flight. The local flight originated from a private airstrip (Scotty's Field) near Altus at 1130. According to the pilot, the airplane operated "normally" during the morning spray runs. The pilot stated, he was flying east, executing his final pass in a field (empty hopper) when he heard a "loud noise" and the engine lost total power. The pilot began looking for a forced landing location and straight ahead was a creek, to the south was a creek, and to the north was a ditch and a power line. The pilot attempted to turn the airplane 180 degrees; however, the airplane impacted the ground, slid approximately 200 feet and came to rest upright. During the forced landing, one wing partially separated from the airframe. The Pratt & Whitney (P&W) Canada PT6A-6 turboprop engine (serial number PCE 20068) was examined at a P&W Canada Facility, St. Hubert, Canada, and was overseen by the Transportation Safety Board of Canada. The engine, which was manufactured in 1964, had accumulated 4,343.1 hours since overhaul (10,586.7 hours total time). The engine exhibited impact damage and the reduction gear box was separated. The exhaust duct was separated in two sections; one piece remained attached to the gas generator and displayed deformation and impact marks consistent with that from turbine blades, and the second piece remained attached to the reduction gear box. The gas generator and accessory gearbox were not damaged. The reduction gearbox chip detector contained fine metallic debris and dirt. The oil and fuel filters were clean. The compressors 1st, 2nd, and 3rd stage blade tips were circumferentially rubbed, and contact was observed on their respective shrouds. The compressors 1st, 2nd, and 3rd stage stator vanes were deformed in the direction of rotation, and the tips were circumferentially rubbed. The centrifugal impeller and shroud displayed circumferential rubbing. The combustion sections chamber liner exhibited heat distress cracking in the vicinity of the fuel nozzle bosses. The compressor turbine guide vane ring airfoils displayed impact damage on the trailing edge downstream side. The compressor turbine (CT) blade airfoils were all fractured between midspan and the blade root. The CT disc exhibited witness marks, consistent with the disc moving axially. The turbine section's inlet turbine temperature probes (ITT) were burnt. The power turbine guide vane ring airfoil leading edges displayed impact damage on the leading edges of the airfoils. Several power turbine blades exhibited damage, consistent with that from a CT blade. The reduction gear box and accessory gear box displayed no indications of operational distress. Additionally, one glow plug (ignition system) exhibited heat distress in its element area. The CT assembly (disk and blades) was examined by the P&W Canada Materials Laboratory. One blade, which was numbered 22 for the purpose of identification and analysis, exhibited ripples in the area of its fracture, consistent with creep. Decohesion at grain boundaries was observed on the concave side of the blade and the coating was not cracked, also consistent with blade fracturing due to creep (rather than by impact). Examination of the remaining blades revealed features consistent with fracture due to impact. ## Aircraft - Registration: [N57597](https://openairdocs.org/deregistered/N57597-2018-01-25), registration cancelled 2018-01-25, S/N 36-7560132, built 1975 (OpenAirDocs) - Reported make and model: Piper PA-36-285 - Registry model: [Piper PA-36-285](https://openairdocs.org/model/piper-pa-36-285) (registry code 7103610) (OpenAirDocs) - Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs) - Category: Airplane - Serial number: 36-7560132 - Airframe hours: 4471.3 - Engines: Pratt & Whitney Canada PT6A-6 525 horsepower turbo prop - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: Altus Ag-Air Inc - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, April 15, 2002, 14 hours before - Departed: NONE, Altus, OK ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 43; injuries: none; commercial; airplane ratings: single-engine land; medical: class 2; last flight review May 2, 2002; seat: center; flight hours: 12,200 total, 2,500 in this make and model, 12,075 as pilot in command, 200 in the last 90 days, 100 in the last 30 days, 6 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: variable at 2 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 95 °F, dew point 70 °F - Altimeter: 30.06 inHg - Observed at: LTS, 10 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 20020802016609A](https://openairdocs.org/incident/20020802016609A), Aug 2, 2002: Piper PA36285, Altus, OK, No damage. (.19) On August 2, 2002, at 1220 central daylight time, a Piper PA-36-285 single-engine agricultural airplane, N57597, was substantially damaged during a… ## Other investigations on N57597 (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 FTW76FQG81](https://openairdocs.org/ntsb/FTW76FQG81), Jun 19, 1976: Piper PA-36 (N57597), Earth, TX, substantial damage ## Docket (2 files) The files NTSB released with the investigation on July 7, 2003, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=55363. 10.1 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 3.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40465776&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Engine Teardown Report (Courtesy of P & W of Canada) (item 2, .PDF, 6.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40465777&FileExtension=.PDF&FileName=Engine%20Teardown%20Report%20(Courtesy%20of%20P%20%26%20W%20of%20Canada)-Master.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.