# NTSB CEN15LA238: Piper PA-25-235, N7279Z, Omega, OK, May 11, 2015 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 10, 2015, 20:15 local (May 11, 2015, 01:15 UTC) - Place: Omega, OK - Coordinates: 35.870277, -98.197776 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=35.8703&lon=-98.1978&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report May 16, 2016 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA Flight Stansdards District Office - NTSB case key (mKey): 91207 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN15LA238 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/91207/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=91207 - Page: https://openairdocs.org/ntsb/CEN15LA238 ## Probable cause Improper base metal preparation or contamination of the No. 5 cylinder wall before it was coated, which resulted in the coating peeling off of the cylinder wall and contaminating the engine oil and the subsequent partial loss of engine power. ## 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-25-235, 1 case](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=7102504), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md) - [Manufacture/production: equipment manufacture](https://openairdocs.org/ntsb-findings/04013010): Organizational issues › Development · Manufacturer (probable cause); cases with it: [Piper PA-25-235, 1 case](https://openairdocs.org/ntsb-findings/04013010/cases.md?model=7102504), [All aircraft, 36 cases](https://openairdocs.org/ntsb-findings/04013010/cases.md) - [Object/animal/substance: fence/fence post](https://openairdocs.org/ntsb-findings/03022047): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Piper PA-25-235, 2 cases](https://openairdocs.org/ntsb-findings/03022047/cases.md?model=7102504), [All aircraft, 313 cases](https://openairdocs.org/ntsb-findings/03022047/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Piper PA-25-235, 5 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=7102504), [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-25-235, 11 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=7102504), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-landing roll: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Piper PA-25-235, 28 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=7102504), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The commercial pilot was conducting an agricultural application flight. During the flight, the airplane was unable to maintain altitude, and the pilot conducted an emergency landing on a dirt road. During the landing roll, the left wing struck a fence, crushing the leading edge. The pilot reported that the oil temperature was extremely high and that the engine was having a problem producing power. A postaccident engine examination revealed metal particles in the engine oil, oil pump, and oil sump. The oil was black and smelled burnt. Coating was peeling off of the No. 5 cylinder wall. Energy dispersive spectroscopy analysis of the cylinder base metal produced a spectrum consistent with a steel alloy; the spectrum of the coating was consistent with a nickel-silicon carbide. It is likely that the coating was peeling either due to improper base metal preparation or contamination of the cylinder wall before it was coated, which resulted in poor bond strength between the coating and inner wall of the barrel. The metal particles from the peeled coating contaminated the engine oil and resulted in the partial loss of power. ## Factual narrative On May 11, 2015, about 2015 central daylight time, the engine on a Piper PA-25-235, N7279Z, overheated and lost partial power. The pilot was unable to maintain altitude and was forced to make an emergency landing on a dirt road near Omega, Oklahoma. During the landing roll, the left wing struck a fence, crushing the leading edge and spinning the airplane around. The pilot was not injured. The airplane was registered to and operated by a private individual under the provisions of 14 Code of Federal Regulations Part 137 as an aerial application flight. Visual meteorological conditions prevailed at the time of the accident, and no flight plan had been filed. The local flight originated from Watonga Regional Airport (KJWG), about 1930.The pilot told a first responder and a Federal Aviation Administration (FAA) inspector that the oil temperature was extremely high and the engine was having a problem making power. The recovery crew said there was fuel in the fuel tanks. The accident site was on County Road E 830, about 0.2 miles east of County Road N2680 in Omega, Oklahoma, or about 11.2 miles east and 2 miles south of Watonga, Oklahoma. On June 17, 2015, the engine was examined at Air Salvage of Dallas, Lancaster, Texas, under the auspices of the National Transportation Safety Board. The investigator reported finding metal particles in the engine oil, oil pump, and oil sump. On July 31, the investigator partially disassembled the engine and said the number 2 compression piston ring on the number 4 piston had a broken ring. The number 5 cylinder had chrome peeling off the cylinder wall. He noted the piston rings were also chrome plated. There was evidence of a light oil leak on the top back section of the engine. The oil was black and smelt "burnt." According to the maintenance logbook, the engine, a Lycoming O-540-G1A5, serial number L-23273-40, was manufactured on July 9, 1981. The following are pertinent entries: • August 1, 1981: The engine was installed in N8731L • February 13, 1992: The engine was removed from N8731L. Engine total time was 858.9 hours. • September 20 1993: The engine was installed in N7279Z. Tachometer time was 4,233.0 hours, and engine total time was 859.9 hours. • August 1, 2006: The engine was overhauled using six ECI nickel carbide cylinders. Tachometer time was 5,042.0 hours, and engine total time was 1,613.81 hours • April 28, 2011: Six new ECI nickel carbide cylinders were installed. Tachometer time was 5,252.5 hours, and engine total time was 1,824.31 hours. • July 5, 2013: Cylinders 1 and 2 were removed, honed, re-ringed, and reinstalled. Tachometer time was 5,320.71 hours, and engine total time was 1,892.52 hours. Other entries between these dates were routine annual and 100-hour inspections. At the time of the accident, the tachometer read 5,448.16 hours, and the engine had accrued 2,019.97 hours since new. Cylinder and piston number 5 and associated rings were removed and shipped to the National Transportation SafetyBoard's Materials Laboratory for metallurgical examination. According to its report, dated February 22, 2016, the cylinder was manufactured by Engine Components, Inc., or ECi. The coating on the upper surface of the cylinder barrel had peeled away. The thickness of the coating measured approximately 0.0058 inch. Energy dispersive spectroscopy (EDS) analysis of the cylinder (base metal) produced a spectrum that contained a major elemental peak of iron and minor elemental peaks of nickel, chromium, silicon, and carbon, consistent with a steel alloy. The spectrum of the coating contained a major elemental peak of nickel and minor elemental peak of silicon, carbon, and oxygen, consistent with a nickel silicon carbide A wedge test, using the tip of a screw driver, revealed the inner coating could be peeled away from the top half portion of the barrel, ranging from "easy" to "moderate," but the inner coating could not be removed from the bottom half portion of the barrel. ## Aircraft - Registration: [N7279Z](https://openairdocs.org/deregistered/N7279Z-2018-09-15), registration cancelled 2018-09-15, S/N 25-3219, built 1965 (OpenAirDocs) - Reported make and model: PIPER PA-25-235 - Registry model: [Piper PA-25-235](https://openairdocs.org/model/piper-pa-25-235) (registry code 7102504) (OpenAirDocs) - Registry engine: [Lycoming 0-540 series](https://openairdocs.org/engine/lycoming-0-540-series) (registry code 41532, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 25-3219 - Year built: 1965 - Airframe hours: 5396 - Engines: Lycoming O-540-B2B5 235 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, March 18, 2015 - Departed: KJWG, Watonga, OK - Destination: KJWG, Watonga, OK - Equipment: Stall warning system, Handheld GPS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 56; injuries: none; commercial; airplane ratings: single-engine land; medical: class 2, with waivers/limitations; last flight review March 3, 2015; seat: single; restraint: 5-point; flight hours: 1,600 total, 900 in this make and model, 70 in the last 90 days ## Weather - Conditions: Visual (VMC), Dusk - Wind: 350° at 4 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 59 °F, dew point 50 °F - Altimeter: 30.20 inHg - Observed at: KJWG, 11 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 20150511013279A](https://openairdocs.org/incident/20150511013279A), May 11, 2015: Piper PA-25-235, Omega, OK, Substantial damage. On may 10, 2015 at approximately 1950 central standard time (CST) an emergency landing was made by pilot while performing aerial agricultural operations in… ## Docket (6 files) The files NTSB released with the investigation on March 18, 2016, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=91207. 1.7 MB in all. - FAA Inspector's Statement (item 1, .PDF, 358 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40437786&FileExtension=.PDF&FileName=FAA%20Inspector%27s%20Statement-Master.PDF - Record of Telephone Conversations with FAA Inspector Les Williams (item 2, .PDF, 66 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40437787&FileExtension=.PDF&FileName=Record%20of%20Telephone%20Conversations%20with%20FAA%20Inspector%20Les%20Williams-Master.PDF - E-Mails from NTSB Investigator Craig Hatch (item 3, .PDF, 21 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40437788&FileExtension=.PDF&FileName=E-Mails%20from%20NTSB%20Investigator%20Craig%20Hatch-Master.PDF - Materials Laboratory Factual Report No. 16-017 (item 4, .PDF, 243 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40437789&FileExtension=.PDF&FileName=Materials%20Laboratory%20Factual%20Report%20No.%2016-017-Master.PDF - Excerpts from the Engine Maintenance Logbook (item 5, .PDF, 659 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40437790&FileExtension=.PDF&FileName=Excerpts%20from%20the%20Engine%20Maintenance%20Logbook-Master.PDF - Report Photos (item 6, .PDF, 401 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40437791&FileExtension=.PDF&FileName=Report%20Photos-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.