# NTSB WPR19LA179: Stinson 108, N6116M, Caldwell, ID, June 27, 2019 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 3 · Limited · Final report - Date: June 27, 2019, 06:30 local (12:30 UTC) - Place: Caldwell, ID · Airport perimeter - Coordinates: 43.659969, -116.63075 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.6600&lon=-116.6308&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach-VFR pattern downwind: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: FAA - NTSB case key (mKey): 99729 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR19LA179 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/99729/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=99729 - Page: https://openairdocs.org/ntsb/WPR19LA179 ## Probable cause A total loss of engine power during approach due to a failed piston. The reason for the piston failure could not be determined based on the available information. ## 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 · Unknown/Not determined (probable cause); cases with it: [Stinson 108-3, 2 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=9230408), [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 · Failure (probable cause); cases with it: [Stinson 108-3, 2 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=9230408), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/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 downwind: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Stinson 108-3, 5 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=9230408), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Landing: Landing area undershoot](https://openairdocs.org/ntsb-events/370); cases with it: [Stinson 108-3, 1 case](https://openairdocs.org/ntsb-events/370/sequence.md?model=9230408), [All aircraft, 201 cases](https://openairdocs.org/ntsb-events/370/sequence.md) - [Landing: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Stinson 108-3, 15 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=9230408), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot was practicing takeoffs and landings in the airport traffic pattern when the engine lost all power as he was turning onto the base leg of the pattern. He turned the airplane toward final approach, but it landed hard short of the runway, struck an airport perimeter fence, and nosed over, coming to rest inverted. A postaccident examination of the airplane revealed metallic debris on the oil dipstick tube and cap, with significant oil residue on the belly of the airplane. The pilot, who performed the engine overhaul 25 hours before the accident flight, performed a cursory examination following the accident and found a broken piston and metal fragments in the intake tubes that caused the intake valves to stick open. The cause of the piston failure could not be determined based on the available information. ## Factual narrative On June 27, 2019, about 0630 mountain daylight time, a Stinson 108-3, N6116M was substantially damaged when it was involved in an accident near Caldwell, Idaho. The pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot, he was practicing takeoffs and landings in the airport traffic pattern. When the airplane was in the turn between the downwind and base legs with the flaps deployed, the engine ceased developing power. The pilot applied carburetor heat, switched fuel tanks, and attempted to restart the engine but was unsuccessful. He then maneuvered the airplane from base leg to final and the airplane landed hard in a field short of the runway. The airplane struck an airport perimeter fence, nosed over, and came to rest inverted. A review of the photographs furnished by the Federal Aviation Administration (FAA) revealed substantial damage to the fuselage and wings. An on-scene examination of the airplane by the FAA revealed that the flaps were in the up position and the carburetor heat was in the off position. The fuel tanks contained fuel, the engine had a supply of oil, and the air filter was not blocked from the outside. An examination of the engine revealed that the oil dip stick tube and cap had significant amounts of “ferrous and non-ferrous” debris and an automotive remote bypass oil filter system was installed. The inspector added that the pilot conducted his own preventative maintenance. The pilot was not a certificated airframe and powerplant mechanic. According to maintenance records, a certificated airframe and powerplant mechanic reinstalled the engine on March 27, 2019, with a total engine time of 2,500 hours. The mechanic added that the engine had been overhauled by the pilot 25 flight hours before the accident flight. He further remarked that he did not physically supervise the pilot during the overhaul and that the pilot used maintenance manuals to complete the overhaul. The logbook entry for the installation of the overhauled engine stated that the overhaul consisted of the following: - Magnafluxed crankshaft and other internal steel parts - Replaced camshaft, bearings, pistons, rings, valves, seals, and gaskets - Both magnetos were fitted with new points and condensers - Carburetor was fitted with new float and needle - Oil cooler hoses and oil pressure hoses were replaced A cursory postaccident examination of the engine performed by the pilot revealed that “a piston came apart, breaking into small pieces that made their way back into the intake tubes [subsequently] sticking the valves open.” No further information or pictures were provided by the pilot regarding his engine examination. Furthermore, the wreckage and the engine were no longer available for a follow-up examination. ## Aircraft - Registration: [N6116M](https://openairdocs.org/deregistered/N6116M-2022-02-05), registration cancelled 2022-02-05, S/N 108-4116, built 1948 (OpenAirDocs) - Reported make and model: Stinson 108 (3) - Registry model: [Stinson 108-3](https://openairdocs.org/model/stinson-108-3) (registry code 9230408) (OpenAirDocs) - Registry engine: [Franklin 6A4165 series](https://openairdocs.org/engine/franklin-6a4165-series) (registry code 27025, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 108-4116 - Year built: 1948 - Airframe hours: 2481 - Engines: Lycoming O-435 SERIES 190 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, March 27, 2019, 25 hours before - Departed: KEUL, Caldwell, ID - Airport: EUL, Caldwell Industrial - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 51; injuries: none; private; airplane ratings: single-engine land; medical: class 3, waiver time limited special; last flight review March 1, 2018; seat: left; restraint: 3-point; flight hours: 300 total, 250 in this make and model, 300 as pilot in command, 25 in the last 90 days, 15 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 280° at 8 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 57 °F, dew point 46 °F - Altimeter: 29.93 inHg - Observed at: KEUL, 1 nm away - METAR: KEUL 271156Z AUTO 28008KT 10SM CLR 14/08 A2993 RMK AO2 SLP114 T01390083 10206 20139 53017= ## 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 20190627008129A](https://openairdocs.org/incident/20190627008129A), Jun 27, 2019: Stinson 108-3, Caldwell, ID, Destroyed. On June 27th at approximately 0635 N6116M was destroyed while landing short of runway 30 at Caldwell Industrial Airport (keul) due to a loss of engine power.… ## Other investigations on N6116M (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 SEA68F0254](https://openairdocs.org/ntsb/SEA68F0254), Mar 13, 1968: Stinson 108-3 (N6116M), Yakima, WA, substantial damage ## Docket (7 files) The files NTSB released with the investigation on March 1, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=99729. 29.8 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 2.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13003127&FileExtension=pdf&FileName=6120%20179_Redacted-Rel.pdf - Memorandum for record a�� email, pilot (item 2, PDF, 2 pages, 150 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13002744&FileExtension=pdf&FileName=MEMORANDUM%20FOR%20RECORD%20-%20Pilot%20179-Rel.pdf - FAA inspector statement (item 3, PDF, 1 page, 213 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13002734&FileExtension=pdf&FileName=Federal%20Aviation%20Administration%20Inspector%20Statement%20179-Rel.pdf - Memorandum for record - FAA inspector (item 4, PDF, 1 page, 153 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13002871&FileExtension=pdf&FileName=MEMORANDUM%20FOR%20RECORD%20-%20FAA%20Inspector%20179-Rel.pdf - Logbook entry of reinstalled engine (item 5, PDF, 1 page, 10.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13003325&FileExtension=pdf&FileName=Logbook%20Entry%20of%20Overhauled%20Engine%20Installation%20179_Redacted-Rel.pdf - Logbook entry of most recent annual inspection 179 (item 6, PDF, 1 page, 11.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13003147&FileExtension=pdf&FileName=Most%20Recent%20Annual%20Entry%20of%20Accident%20Airplane%20179_Redacted-Rel.pdf - Accident photos (item 7, PDF, 4 pages, 5.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13003315&FileExtension=pdf&FileName=Accident%20Photos%20179-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.