# NTSB CEN11LA487: Ayres S2R, N70216, Burlington, CO, July 18, 2011 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 18, 2011, 05:55 local (11:55 UTC) - Place: Burlington, CO - Coordinates: 39.238887, -102.284446 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.2389&lon=-102.2844&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach-VFR pattern final: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report May 21, 2012 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA/FSDO - NTSB case key (mKey): 81161 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN11LA487 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/81161/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=81161 - Page: https://openairdocs.org/ntsb/CEN11LA487 ## Probable cause A loss of engine power for undetermined reasons. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Thrush S2R-T34, 1 case](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=8380307), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) - [Engine (turbine/turboprop)](https://openairdocs.org/ntsb-findings/01057200): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Thrush S2R-T34, 1 case](https://openairdocs.org/ntsb-findings/01057200/cases.md?model=8380307), [All aircraft, 67 cases](https://openairdocs.org/ntsb-findings/01057200/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach-VFR pattern final: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Thrush S2R-T34, 1 case](https://openairdocs.org/ntsb-events/341/sequence.md?model=8380307), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Thrush S2R-T34, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=8380307), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) ## Analysis The airplane was on a 2-mile final approach when its turbine engine lost total power. The pilot said that he did not look at the engine gauges and that there were no aural warnings. He made a forced landing to a field, and the airplane bounced and came to rest just forward of the first touch down spot. A postaccident examination of the airframe, available fuel supply, engine, and components revealed no preimpact anomalies or mechanical deficiencies that would have precluded the engine from operating. The source of the power loss could not be determined. ## Factual narrative HISTORY OF FLIGHT On July 18, 2011, at 0555 mountain daylight time, N70216, a Thrush Aircraft Incorporated S2R-T34, sustained substantial damage after a loss of power on final approach to the Kit Carson County Airport (ITR), Burlington, Colorado. The commercial pilot was not injured. The airplane was registered to and operated by Stratton Equity Corporation, Stratton, Colorado. Visual meteorological conditions prevailed and no flight plan was filed for the local agricultural spraying flight conducted under 14 Code of Federal Regulations Part 137. The flight originated at ITR at 0520. The pilot stated that he was returning back to the airport and was on a two mile final when the engine "just died." He said it got "real quiet" and the control column got "heavy." The pilot said he did not look at the engine gauges and there were no aural warnings. However, he did cycle the fuel control lever. Due to the low altitude, the pilot established a glide and subsequently landed hard in a field. The airplane bounced and came to rest about 15 yards from where it first landed. The pilot also said that before the flight, he performed a preflight inspection, which included only draining the header tank for several seconds; however, he did not drain the fuel into a clear jar to check for water or debris. The pilot reported that the airplane was kept in a hangar and it had been washed the day before the accident. PERSONNEL INFORMATION The pilot held a commercial pilot certificate for airplane single-engine land. His last FAA second class medical was issued on May 12, 2011. He reported a total of 2,302 total flight hours, of which, 178 hours were in the same make and model as the accident airplane. The pilot also reported that he had flown 221 hours in the last 90 days. AIRCRAFT INFORMATION A review of the engine logbooks revealed that the Pratt & Whitney PT6A-34AG (750 hp) turbo-prop engine was manufactured in April 2010. At the time of the accident, the engine had accrued a total of 171.3 hours since new and 172 cycles. WRECKAGE AND IMPACT INFORMATION On August 1, 2011, the investigator-in-charge (IIC) performed an examination of the airframe and engine along with a representative of Pratt & Whitney Canada. The firewall was wrinkled and each wing sustained leading edge impact damage. The engine was still installed on the airframe and the three-bladed propeller had been removed. All three propeller blades were bent aft about 90 degrees and appeared feathered. An external examination of the engine did not reveal any mechanical problems with the power turbine, compressor turbine or compressor assembly. The exhaust case sustained impact damage, which resulted in the power turbine blades contacting the shroud and preventing the power turbine disk and gearbox from rotating. The P3 and Py pneumatic lines were secure at all connection points. The linkages to the fuel control unit (FCU) and the propeller governor were intact and moved freely without binding. The firewallsump (engine side) was drained and approximately four fluid ounces of straw colored fuel (consistent with Jet-A fuel) was inside. A trace amount of debris was noted in the fuel and absent of water. The filter was disconnected and the filter screen had a very light trace of debris. Straw colored fuel was drained from the main fuel line from the sump to the engine. There was a light trace of debris (silicone) observed in the fuel. The engine fuel filter was removed and the bowl was filled with approximately two fluid ounces of straw colored fuel that was absent of debris or water. According to the company that recovered the airplane, approximately 77 gallons of fuel was drained from the airplane’s wings and approximately 8 gallons of fuel was drained from the header tank. The fuel was absent of debris and water. TESTS AND RESEARCH The engine was removed and sent to Dallas Airmotive, Dallas, Texas, where a teardown examination was performed on September 16, 2011, under the supervision of the IIC. After the engine was removed from the sealed crate and placed on a test stand, the lines attached to the fuel control unit (FCU) and the propeller governor were tested for proper installment. The Py line to the propeller governor was slightly loose where it attached to the unit. Shop air was then blown through the line and a soap/water solution was sprayed externally on the line. No leaks were noted. Air was also blown into the P3 line and no leaks were noted. The P3 filter was disassembled and the bowl was absent of debris. The internal components of the filter were absent of debris. The engine driven fuel pump’s metal filter was removed and examined. A trace amount of debris was found on the bottom of the screen. The FCU, compressor bleed valve assembly, and the flow divider and dump valve were removed and bench tested while at Dallas Airmotive. The units operated to standard test specifications and no anomalies were noted. The propeller and over speed governors were also removed and sent to Pratt & Whitney Canada for testing. The units were tested under the supervision of the Transportation Safety Board (TSB) on September 28, 2011. A review of the Pratt and Whitney Accessories Accident Report revealed that the propeller governor was original to the engine when it was delivered. The driveshaft turned freely by hand. The speed setting lever, beta-valve clevis and reset arm moved freely over the full ranges and returned under the influence of their springs. The unit was tested in accordance with Woodward specification TSP-810 Rev. AH. Four of the test points were slightly out of test specifications, indicative of rigging adjustments made in the field after the unit was delivered. The overspeed governor was not on the engine at initial engine delivery. The driveshaft turned freely by hand. There was orange anti-tamper paint on the pilot valve stop screw. The inside of the electrical connector was clean and dry. Lockwire was present at all locations. Theunit was tested in accordance with Woodward drawing A210507. Two of the test points were slightly out of test specifications, indicative of rigging adjustments made in the field. An examination of the airframe, available fuel supply, engine, and accessories revealed no pre-mishap anomalies or mechanical deficiencies that would have precluded the engine from operating at the time of impact. The source of the power loss could not be determined. ## Aircraft - Registration: [N70216](https://openairdocs.org/deregistered/N70216-2020-07-09), registration cancelled 2020-07-09, S/N T34-335, built 2011 (OpenAirDocs) - Reported make and model: AYRES S2R (T34) - Registry model: [Thrush S2R-T34](https://openairdocs.org/model/thrush-s2r-t34) (registry code 8380307) (OpenAirDocs) - Registry engine: [Pratt & Whitney Canada PT6A-34AG](https://openairdocs.org/engine/pratt-whitney-canada-pt6a-34ag) (registry code 52251, turbo-prop) (OpenAirDocs) - Category: Airplane - Serial number: T-34-335 - Airframe hours: 171 - Engines: PRATT AND WHITNEY PT6A-34AG 750 horsepower turbo prop - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Stratton Equity Co-op - Registered owner: Stratton Equity Co-op - Airworthiness certificate: Special, Restricted (Special); Standard, Utility - Last inspection: 100 hour, July 11, 2011 - Departed: ITR, Burlington, CO - Destination: ITR, Burlington, CO - Airport: ITR, Kit Carson County Airport ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 45; injuries: none; commercial; airplane ratings: single-engine land; medical: class 2; seat: center; flight hours: 23,067 total, 178 in this make and model, 2,215 as pilot in command, 221 in the last 90 days ## Weather - Conditions: Visual (VMC), Day - Wind: 160° at 7 knots - Visibility: 8 statute miles - Lowest ceiling: none - Temperature: 70 °F, dew point 55 °F - Altimeter: 29.98 inHg - Observed at: KITR, 1 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 20110718014719A](https://openairdocs.org/incident/20110718014719A), Jul 18, 2011: Thrush Aircraft Inc S2R-T34, Burlington, CO, Substantial damage. On July 18, 2011, a restricted category agricultural aircraft conducted an off-airport landing near the kit carson county airport. VMC conditions existed at… ## Docket (5 files) The files NTSB released with the investigation on April 27, 2012, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=81161. 740 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 405 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40361712&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Record of Conversation - Pilot (item 2, .PDF, 73 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40361713&FileExtension=.PDF&FileName=Record%20of%20Conversation%20-%20Pilot-Master.PDF - Record of Conversation - Steve Rice, North Star Aviation (item 3, .PDF, 69 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40361714&FileExtension=.PDF&FileName=Record%20of%20Conversation%20-%20Steve%20Rice,%20North%20Star%20Aviation-Master.PDF - Synopsis of overspeed and propeller governors factual report (PWC) (item 4, .PDF, 96 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40364687&FileExtension=.PDF&FileName=Synopsis%20of%20overspeed%20and%20propeller%20governors%20factual%20report%20(PWC)-Master.PDF - Release of Aircraft Wreckage, NTSB Form 6120.15 (item 5, .PDF, 98 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40363964&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.