# NTSB CEN15LA279: Mooney M20K, N1168Z, Sheboygan, WI, June 21, 2015 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 21, 2015, 11:30 local (16:30 UTC) - Place: Sheboygan, WI - Coordinates: 43.769721, -87.851669 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.7697&lon=-87.8517&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report September 24, 2015 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA Flight Standards District Office - NTSB case key (mKey): 91414 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN15LA279 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/91414/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=91414 - Page: https://openairdocs.org/ntsb/CEN15LA279 ## Probable cause Oil starvation due to preignition in the No. 5 cylinder as a result of failed spark plugs; the top and sides of the piston head were eroded, which allowed the exhaust gases caused by the preignition to pressurize the crankcase and force engine oil out of the breather tube. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating): recip engine power section](https://openairdocs.org/ntsb-findings/01058520): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Mooney M20K, 4 cases](https://openairdocs.org/ntsb-findings/01058520/cases.md?model=5870220), [All aircraft, 233 cases](https://openairdocs.org/ntsb-findings/01058520/cases.md) - [Fluids: oil](https://openairdocs.org/ntsb-findings/01071020): Aircraft › Fluids/misc hardware · Related operating info (probable cause); cases with it: [Mooney M20K, 1 case](https://openairdocs.org/ntsb-findings/01071020/cases.md?model=5870220), [All aircraft, 174 cases](https://openairdocs.org/ntsb-findings/01071020/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 (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Mooney M20K, 15 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=5870220), [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: [Mooney M20K, 14 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=5870220), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Mooney M20K, 28 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=5870220), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis Shortly after takeoff, the pilot advised air traffic control that he was returning to the airport due to low oil pressure. The engine subsequently lost power, and the pilot was forced to land in a wheat field 5 miles south of the airport. During on-site examination of the airplane, no oil was found in the crankcase, and subsequent examination of the engine and turbocharger revealed that the turbocharger was dry. Further examination of the engine revealed evidence of preignition in the No. 5 cylinder that appeared to have been caused by failed spark plugs. The top and sides of the piston head were eroded, which allowed the exhaust gases caused by the preignition to pressurize the crankcase and force engine oil out of the breather tube. ## Factual narrative On June 21, 2015, about 1130 central daylight time, the pilot of a Mooney M20K, N1168Z, made a forced landing in a wheat field 5 miles south of Sheboygan (KSBM), Wisconsin. The pilot, the sole occupant on board, was not injured. The airplane was substantially damaged. The airplane was registered to and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91 as a personal flight. Instrument meteorological conditions prevailed, and an instrument flight rules flight plan had been filed and activated. The flight originated from KSBM at 1113 and was destined for Elkhart (KEKM), Indiana.Shortly after airplane departed, the pilot advised he was returning to KSBM due to low oil pressure. The airplane lost engine power and the pilot made a forced landing in a wheat field five miles south of the airport. A Federal Aviation Administration (FAA) airworthiness inspector who examined the airplane reported finding no oil in the crankcase. He reported the rear bulkhead was wrinkled and the empennage was twisted. On July 1, 2015, an FAA airworthiness inspector examined the engine and turbocharger. He reported the turbocharger was dry and did not appear to be at fault. On August 17, the FAA airworthiness inspector examined the engine again at a teardown facility in Poplar Grove, Wisconsin. He reported finding evidence of pre-ignition in the number 5 cylinder that appeared to have been caused by failed spark plugs. The top and sides of the piston head were eroded, allowing exhaust gases to pressurize the crankcase and force engine oil out of the breather tube. ## Aircraft - Registration: [N1168Z](https://openairdocs.org/deregistered/N1168Z-2015-10-29), registration cancelled 2015-10-29, S/N 25-0697, built 1982 (OpenAirDocs) - Reported make and model: MOONEY M20K - Registry model: [Mooney M20K](https://openairdocs.org/model/mooney-m20k) (registry code 5870220) (OpenAirDocs) - Registry engine: [Continental TSIO-360 series](https://openairdocs.org/engine/continental-tsio-360-series) (registry code 17019, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 25-0697 - Year built: 1982 - Engines: Continental TSIO-520-MB 210 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: James R. Pawlak - Registered owner: James R. Pawlak - Airworthiness certificate: Standard, Normal - Departed: KSBM, Sheboygan, WI - Destination: KEKM, Elkhart, IN - Flight plan: IFR - Airport: KSBM, Sheboygan County Mem - Equipment: Handheld GPS, Data recorder, Auto-pilot, Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 64; injuries: none; private; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; seat: left; restraint: 3-point; flight hours: 3,570 total, 3,270 in this make and model, 3,570 as pilot in command ## Weather - Conditions: Instrument (IMC), Day - Wind: 150° at 5 knots - Visibility: 1.75 statute miles - Lowest ceiling: 3,100 ft broken - Temperature: 70 °F, dew point 66 °F - Altimeter: 29.81 inHg - Observed at: KSBM, 5 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 20150621009569A](https://openairdocs.org/incident/20150621009569A), Jun 21, 2015: Mooney Aircraft Corp. M20K, Sheboygan Falls, WI, Substantial damage. June 22, 2015 at 1321 local time an Mooney M20K N1168Z experienced loss of oil pressure then loss of engine power while at cruise phase of flight. The aircraft… ## Docket (11 files) The files NTSB released with the investigation on September 2, 2015, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=91414. 8.2 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40431329&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - E-Mail from Michael J. Pieczynski (item 2, .PDF, 46 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40431330&FileExtension=.PDF&FileName=E-Mail%20from%20Michael%20J.%20Pieczynski-Redacted.PDF - FAA Teardown Report (item 3, .PDF, 55 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40431331&FileExtension=.PDF&FileName=FAA%20Teardown%20Report-Redacted.PDF - Weather Report (item 4, .PDF, 51 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40431332&FileExtension=.PDF&FileName=Weather%20Report-Master.PDF - Photo 1 - Right rear view of N1168Z (item 5, .PDF, 1.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40431333&FileExtension=.PDF&FileName=Photo%201%20-%20Right%20rear%20view%20of%20N1168Z-Master.PDF - Photo 2 - View from right side, looking aft (item 6, .PDF, 1.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40431334&FileExtension=.PDF&FileName=Photo%202%20-%20View%20from%20right%20side,%20looking%20aft-Master.PDF - Photo 3 - Oil filter element (item 7, .PDF, 2.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40431335&FileExtension=.PDF&FileName=Photo%203%20-%20Oil%20filter%20element-Master.PDF - Photo 4 - Number 5 piston head (item 8, .PDF, 320 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40431336&FileExtension=.PDF&FileName=Photo%204%20-%20Number%205%20piston%20head-Master.PDF - Photo 5 – Number 5 cylinder dome (item 9, .PDF, 305 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40431337&FileExtension=.PDF&FileName=Photo%205%20%E2%80%93%20Number%205%20cylinder%20dome-Master.PDF - Photo 6 - Number 5 spark plugs, upper and lower (item 10, .PDF, 288 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40431338&FileExtension=.PDF&FileName=Photo%206%20-%20Number%205%20spark%20plugs,%20upper%20and%20lower-Master.PDF - Photo 7 - Number 5 spark plugs, upper and lower, detailed (item 11, .PDF, 244 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40431339&FileExtension=.PDF&FileName=Photo%207%20-%20Number%205%20spark%20plugs,%20upper%20and%20lower,%20detailed-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.