# NTSB CEN17LA317: Piper PA22, N2591A, Beckville, TX, August 14, 2017 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: August 14, 2017, 10:17 local (15:17 UTC) - Place: Beckville, TX - Coordinates: 32.24361, -94.455833 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=32.2436&lon=-94.4558&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report July 8, 2019 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA Flight Standards, Lycoming Engines - NTSB case key (mKey): 95818 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN17LA317 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/95818/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=95818 - Page: https://openairdocs.org/ntsb/CEN17LA317 ## Probable cause A stuck exhaust valve, which resulted in the failure of the valve and a loss of engine power. Contributing to the valve failure and loss of engine power was the extended time since the last overhaul. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating): recip eng cyl section](https://openairdocs.org/ntsb-findings/01058530): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Piper PA-22-135, 1 case](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=7102206), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md) - [Engine (reciprocating): recip eng cyl section](https://openairdocs.org/ntsb-findings/01058530): Aircraft › Aircraft power plant · Fatigue/wear/corrosion (probable cause); cases with it: [Piper PA-22-135, 1 case](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=7102206), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md) - [Engine (reciprocating)](https://openairdocs.org/ntsb-findings/01058500): Aircraft › Aircraft power plant · Not serviced/maintained (probable cause); cases with it: [Piper PA-22-135, 1 case](https://openairdocs.org/ntsb-findings/01058500/cases.md?model=7102206), [All aircraft, 497 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340); cases with it: [Piper PA-22-135, 1 case](https://openairdocs.org/ntsb-events/340/sequence.md?model=7102206), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) - [Enroute-cruise: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Piper PA-22-135, 1 case](https://openairdocs.org/ntsb-events/342/sequence.md?model=7102206), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Piper PA-22-135, 2 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=7102206), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) ## Analysis The commercial pilot reported that, about 2 hours into the pipeline surveillance flight, the engine began running roughly. He initially established a course to a nearby airport; however, the engine was not producing enough power to maintain altitude. He subsequently executed a forced landing to a pasture, which resulted in substantial damage to the left wing. A postaccident engine examination revealed that the No. 3 cylinder exhaust valve fractured at the stem seat. Metallurgical examination revealed that the fracture features were consistent with torsional loading at fracture. The stem was tapered adjacent to the fracture, and interconnected voids and surface oxidation were observed at the fracture surface. The presence of voids, tapering of the stem, and oxidation are consistent with high-temperature deformation under stress. Further examination revealed grain structure and subsurface oxidation consistent with exposure to elevated temperatures over an extended period of time, consistent with a stuck valve condition. Factors leading to stuck exhaust valves include excessive engine temperature, dirty or contaminated engine oil, high lead content fuels, hot engine shut-downs, and poor engine baffling. Running engines past the recommended overhaul interval or at elevated temperatures risks creating an exhaust valve fatigue event. The investigation was unable to determine the exact combination of elements that led to the stuck valve. However, based on the available maintenance records, the most recent engine overhaul was completed in 1968, and it is likely that the extended 49-year interval contributed to the stuck valve. While this exceeded the engine manufacturer's 12-year or 1,500-hour time between overhaul interval, the operator was not required to comply under current regulations due to the type of operation. ## Factual narrative On August 14, 2017, about 1017 central daylight time, a Piper PA22-135 airplane, N2591A, was substantially damaged during a forced landing following a partial loss of engine power near Beckville, Texas. The pilot sustained minor injuries. The airplane was registered to and operated by private individuals as a Title 14 Code of Federal Regulations Part 91 flight. Day visual meteorological conditions prevailed. The flight was not operated on a flight plan. The pipeline surveillance flight originated from Cypress River Airport (24F), Jefferson, Texas, about 0800. The intended destination was the Gladewater Municipal Airport (07F), Gladewater, Texas.The pilot reported fueling the airplane at 24F before departing on his planned pipeline surveillance route. About 2 hours into the flight, en route to 07F, the engine began running rough. He initially established a course to Panola County Airport (4F2) about 8 miles away. However, the engine was not producing enough power to maintain altitude. He subsequently executed a forced landing to a pasture, which resulted in substantial damage to the left wing. A postaccident engine examination revealed that the no. 3 cylinder exhaust valve fractured at the stem seat. The intake valve appeared intact. The cylinder walls exhibited impact and scraping marks consistent with secondary damage from the separated exhaust valve head. The piston had fractured at several locations; the features appeared consistent with overstress fractures. The piston crown exhibited multiple impact marks similar to the cylinder walls. Metallurgical examination revealed that the fracture surface on the separated valve head was obliterated consistent with secondary mechanical damage after separation from the stem. The mating fracture surface on the stem was relatively undamaged. The fracture features were consistent with torsional loading at fracture. The stem was tapered adjacent to the fracture, and interconnected voids were observed at the fracture surface. Surface oxidation, sub-surface intergranular oxidation and deposits of lead-based compounds were also observed. The presence of the voids, the tapering of the stem, and the oxidation are consistent with high-temperature deformation under stress. Further examination revealed grain structure and sub-surface oxidation consistent with exposure to elevated temperatures over an extended period of time. The available airplane maintenance records included an entry, dated April 5, 1968, that noted: "major overhaul of engine this date;" the associated tachometer time was 1,153 hours. No subsequent entries regarding an engine overhaul were observed in the records. The most recent annual inspection was completed on April 22, 2017, at 1,770.4 hours tachometer time. The current owner purchased the airplane on April 23, 2017. The most recent engine maintenance consisted of an oil change on August 1, 2017. The tachometer indicated 1,986.5 hours at the accident site. The engine manufacturer recommendedtime between overhaul (TBO) was 1,500 hours operating time or 12 calendar years. Federal Aviation Administration regulations do not require Part 91 operators to comply with an engine manufacturer's TBO interval provided the engine meets annual inspection requirements. ## Aircraft - Registration: [N2591A](https://openairdocs.org/deregistered/N2591A-2021-03-06), registration cancelled 2021-03-06, S/N 22-876, built 1952 (OpenAirDocs) - Reported make and model: PIPER PA22 (135) - Registry model: [Piper PA-22-135](https://openairdocs.org/model/piper-pa-22-135) (registry code 7102206) (OpenAirDocs) - Registry engine: [Lycoming 0-290 series](https://openairdocs.org/engine/lycoming-0-290-series) (registry code 41506, 4 cycle) (OpenAirDocs) - Category: Airplane - Serial number: 22-876 - Year built: 1952 - Airframe hours: 1986 - Engines: LYCOMING O-290-D2 135 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial observation, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, April 22, 2018, 216 hours before - Departed: 24F, Jefferson, TX - Destination: 07F, Gladewater, TX ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 60; injuries: minor; commercial; airplane ratings: single-engine land; medical: class 2, with waivers/limitations; last flight review June 26, 2016; seat: left; restraint: lap only; flight hours: 5,941 total, 203 in this make and model, 240 in the last 90 days, 70 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 230° at 8 knots - Visibility: 8 statute miles - Lowest ceiling: none - Temperature: 81 °F, dew point 79 °F - Altimeter: 29.90 inHg - Observed at: GGG, 20 nm away ## Docket (5 files) The files NTSB released with the investigation on May 1, 2019, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=95818. 19.1 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40472353&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Materials Laboratory Factual Report (item 2, .PDF, 11.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40472354&FileExtension=.PDF&FileName=Materials%20Laboratory%20Factual%20Report-Master.PDF - Maintenance Records - Engine (item 3, .PDF, 2.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40472355&FileExtension=.PDF&FileName=Maintenance%20Records%20-%20Engine-Master.PDF - Lycoming Service Instruction - Time Between Overhaul (TBO) Schedules (item 4, .PDF, 2.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40472356&FileExtension=.PDF&FileName=Lycoming%20Service%20Instruction%20-%20Time%20Between%20Overhaul%20(TBO)%20Schedules-Master.PDF - Statement of Party Representatives to NTSB Investigation (item 5, .PDF, 526 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40472357&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-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.