# NTSB WPR22LA177: Piper PA-12, N3960M, Enterprise, OR, May 14, 2022 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: May 14, 2022, 14:30 local (21:30 UTC) - Place: Enterprise, OR · Wheat field - Coordinates: 45.415963, -117.25115 - Nearby events: https://openairdocs.org/map.md?lat=45.4160&lon=-117.2511&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: FAA-FSDO - NTSB case key (mKey): 105088 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR22LA177 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/105088/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=105088 - Page: https://openairdocs.org/ntsb/WPR22LA177 ## Probable cause The inadequate maintenance and inspection of the crankshaft expansion plug, which resulted in the separation of the expansion plug from the crankshaft and the subsequent loss of oil and windshield obstruction during departure. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating): recip eng oil sys](https://openairdocs.org/ntsb-findings/01058550): Aircraft › Aircraft power plant · Incorrect service/maintenance; cases with it: [Piper PA-12, 1 case](https://openairdocs.org/ntsb-findings/01058550/cases.md?model=7101202), [All aircraft, 130 cases](https://openairdocs.org/ntsb-findings/01058550/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) (defining event); cases with it: [Piper PA-12, 1 case](https://openairdocs.org/ntsb-events/340/sequence.md?model=7101202), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) ## Analysis The pilot reported that shortly after departure, about 700 ft above ground level (agl), the windshield was sprayed with oil. He turned and entered the downwind leg of the traffic pattern and attempted to land on the runway. He reported that he was too high during the approach and aborted the landing. On the second attempt to land on runway 30, the oil spray was getting worse, and the pilot made a precautionary landing resulting in substantial damage to the fuselage. The postaccident examination of the airplane and interview with the mechanic revealed that the expansion plug was improperly installed and had separated from the end of the crankshaft, causing oil to exit through the propeller spinner resulting in the oil spray on the windshield. ## Factual narrative On May 14, 2022, about 1430 Pacific daylight time, a Piper PA-12 airplane, N3960M, was substantially damaged when it was involved in an accident near Enterprise, Oregon. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that shortly after departure from runway 30 at Enterprise Municipal Airport (8S4), Enterprise, Oregon, about 700 ft agl, the windshield was sprayed with oil. He turned and entered the downwind leg of the traffic pattern and attempted to land on runway 30. He reported that he was too high during the approach and aborted the landing. On the second attempt to land on runway 30, the oil spray was getting worse, and he stated that he “flew the plane onto the ground” east of the airport. The airplane impacted the ground resulting in damage to the fuselage. Postaccident examination of the engine revealed a loose crankshaft plug within the crankshaft. The pilot reported that about 50 flight hours before the accident, the airplane’s windshield was sprayed with oil when his friend was flying the airplane after an annual inspection during which the crankshaft plug was removed and reinstalled. The airplane landed safely, and it was determined that the expansion plug from the end of the crankshaft separated, causing oil to exit through the propeller spinner. The mechanic who performed the annual inspection reinstalled the expansion plug and the airplane operated about 39 hours before the accident flight. The FAA conducted an interview with the mechanic and it was determined that improper tools and technique were used when reinstalling the expansion plug. On both occasions, no record of reinstalling the expansion plug was added to the maintenance records. The Lycoming Service Instruction No. 1583, “Front Expansion Plug Replacement,” (SI1583), provides detailed instruction and tooling required for the replacement of the front expansion plug. ## Aircraft - Registration: [N3960M](https://openairdocs.org/aircraft/N3960M), registered now, S/N 12-2843, built 1947 (OpenAirDocs) - Reported make and model: PIPER PA-12 - Registry model: [Piper PA-12](https://openairdocs.org/model/piper-pa-12) (registry code 7101202) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 12-2843 - Year built: 1947 - Engines: Lycoming O-320-B3B 160 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Rouse Kenneth L - Airworthiness certificate: Standard, Normal - Last inspection: Annual, October 20, 2021, 39 hours before - Airport: 8S4, Enterprise Municipal Airport, runway 30, 2,850 × 50 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 45; injuries: none; student; medical: class 3, without waivers/limitations; seat: front; flight hours: 7.6 total ## Weather - Conditions: Visual (VMC), Day - Visibility: 10 statute miles - Lowest ceiling: 5,000 ft broken - Temperature: 55 °F, dew point 43 °F - Altimeter: 30.14 inHg - Icing: Unknown - Turbulence: Unknown - Observed at: KJSY, 3 nm away - METAR: KJSY 142135Z AUTO 10SM SCT020 SCT025 BKN050 13/06 A3014 RMK AO2 T01300058 TSNO ## 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 20220514007029A](https://openairdocs.org/incident/20220514007029A), May 14, 2022: Piper PA-12, Enterprise, OR, Substantial damage. The student pilot departed runway 30 and at an altitude of 500-600' AGL oil started covering the windshield which was limiting his forward visibility. The… ## Other investigations on N3960M (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 SEA94LA132](https://openairdocs.org/ntsb/SEA94LA132), May 27, 1994: Piper PA-12 (N3960M), Nashua, MT, substantial damage. Probable cause: AIRSPEED WAS NOT MAINTAINED. FACTORS INCLUDE AN INADVERTENT STALL. ## Docket (7 files) The files NTSB released with the investigation on April 10, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=105088. 6.4 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 6 pages, 2.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16708247&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - NTSB initial notification-es (item 2, PDF, 2 pages, 90 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16709227&FileExtension=pdf&FileName=5-17-22%20WPR22LA177_%20105088%20initial%20notification-ES_Redacted-Rel.pdf - FAA examination field notes (item 3, PDF, 1 page, 142 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16708548&FileExtension=pdf&FileName=DMS%20Email%20FAA%20Exam%20Notes_Redacted-Rel.pdf - Maintenance records (item 4, PDF, 2 pages, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16708470&FileExtension=pdf&FileName=Maintenance%20Records_Redacted-Rel.pdf - Lycoming service instruction-front expansion plug replacement (item 5, PDF, 3 pages, 580 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16887132&FileExtension=pdf&FileName=SI1583_Front_Expansion_Plug_Replacement-Rel.pdf - Photo array-accident site (courtesy of the pilot) (item 6, PDF, 3 pages, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16708257&FileExtension=pdf&FileName=Photo%20Array-Accident%20Site%20(Courtesy%20of%20the%20Pilot)-Rel.pdf - Photo array-faa engine examination (item 7, PDF, 3 pages, 435 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=16708338&FileExtension=pdf&FileName=Photo%20Array-FAA%20Examination-Rel.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.