# NTSB WPR14LA079: Stinson 108 1, N8848K, Lodi, CA, December 27, 2013 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: December 27, 2013, 10:55 local (18:55 UTC) - Place: Lodi, CA - Coordinates: 38.148887, -121.079719 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.1489&lon=-121.0797&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-climb to cruise: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report January 12, 2015 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 88596 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR14LA079 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/88596/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=88596 - Page: https://openairdocs.org/ntsb/WPR14LA079 ## Probable cause The fatigue failure of the crankshaft, which resulted in a total loss of engine power and subsequent forced landing. ## 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 · Fatigue/wear/corrosion (probable cause); cases with it: [Stinson 108-1, 2 cases](https://openairdocs.org/ntsb-findings/01058520/cases.md?model=9230404), [All aircraft, 233 cases](https://openairdocs.org/ntsb-findings/01058520/cases.md) - [Terrain: rough terrain](https://openairdocs.org/ntsb-findings/03021015): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Stinson 108-1, 2 cases](https://openairdocs.org/ntsb-findings/03021015/cases.md?model=9230404), [All aircraft, 442 cases](https://openairdocs.org/ntsb-findings/03021015/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-climb to cruise: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) (defining event); cases with it: [Stinson 108-1, 1 case](https://openairdocs.org/ntsb-events/340/sequence.md?model=9230404), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) - [Enroute-climb to cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341); cases with it: [Stinson 108-1, 4 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=9230404), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Landing-landing roll: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Stinson 108-1, 4 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=9230404), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-landing roll: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Stinson 108-1, 6 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=9230404), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) ## Analysis The pilot reported that, shortly after takeoff, the engine began to sputter and that it eventually lost all power. The pilot was unable to return to the airport and initiated a forced landing to an open field. During the landing, the airplane struck a berm, nosed over, and then came to rest inverted. A postaccident examination of the engine revealed that the crankshaft and camshaft had broken adjacent to the accessory section. A metallurgical examination of the crankshaft fracture surfaces revealed a thumbnail-shaped pattern consistent with fatigue that had initiated at the crankshaft surface near the edge of the No. 2 connecting rod journal. It is possible that the fatigue initiated due to the No. 2 connecting rod bearing shifting during operation. The camshaft fracture features were consistent with overstress. Maintenance records indicated that the last annual inspection was completed about 9 months before the accident and that, at that time, the engine had accumulated about 250 hours since major overhaul. ## Factual narrative HISTORY OF FLIGHT On December 27, 2013, about 1055 Pacific standard time, a Stinson 108-1 airplane, N8848K, experienced a loss of engine power, and the pilot made a forced landing in an open field near Lodi, California. The owner/pilot operated the airplane under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. The pilot and one passenger were not injured. The airplane sustained substantial damage to its wings and fuselage when it struck a berm and nosed over during the landing roll out. The airplane had departed from the Kingdon Airpark (O20), Lodi, about 1030, and was destined for the Modesto City-County Airport-Harry Sham Field (MOD), Modesto, California. Visual meteorological conditions prevailed for the local area flight, and no flight plan had been filed. According to a responding deputy from the San Joaquin Sheriff's Department, the pilot reported that shortly after takeoff the engine started to sputter. He turned back to the departure airport, and attempted to restart the engine. After switching fuel tanks, the engine regained full power, then quit completely. The pilot made a forced landing to an open field, which appeared to be free of obstructions. However, during the landing rollout, the airplane struck a berm and nosed over coming to rest inverted. According to a Federal Aviation Administration (FAA) inspector, who responded to the accident site, the airplane traveled about 400 yards before impacting the ditch. The FAA inspector reported that the pilot had just put in new shoulder harness type seatbelts in the airplane. The engine was examined at Plain Parts, Pleasant Grove, California, on January 10, 2014. A visual examination revealed that the right side of the engine crankcase near the accessory section had separated. The spark plugs, rocker box covers, and the top of the engine case were removed. The propeller was manually manipulated back and forth; however, full rotation could not be achieved due to damage to the crankshaft, but visible movement of the crankshaft was noted at the rear of the engine. Investigators reported that the crankshaft and cam shaft near the accessory section had broken, and several bearings had been damaged. The crankshaft with a portion of the number one connecting rod, crankshaft main journal bearing, crankshaft connecting rod journal bearing, and a camshaft were shipped to the National Transportation Safety Board (NTSB) metallurgical laboratory in Washington, DC, for further examination. TEST AND RESEARCH The NTSB metallurgical laboratory specialist documented the submitted components; the crankshaft was received in two fractured pieces. The fracture occurred through the web between the numbers one and two connecting rod journals. The fracture face was relatively flat with a thumbnail-shaped pattern, which was consistent with fatigue. The fatigue crack initiated at the crankshaft surface, with the primary fatigue crack propagating through 79 percent of the webcross-section. A second fatigue crack had propagated from the opposite side of the fractured crankshaft web and comprised about 5 percent of the web fracture surface. The remaining fracture surface had features consistent with overstress. The specialists reported that the primary fatigue crack propagated from the surface of the crankshaft near the edge of a darkened area on the number two connecting rod journal. According to the specialist, the fracture features of the camshaft were consistent with overstress. The specialists' report is attached to the public docket for this accident. Maintenance records indicated that during the last annual inspection dated March 12, 2013, the engine had accumulated about 250 hours since the major overhaul. ## Aircraft - Registration: [N8848K](https://openairdocs.org/deregistered/N8848K-2015-12-01), registration cancelled 2015-12-01, S/N 108-1848, built 1947 (OpenAirDocs) - Reported make and model: STINSON 108 1 - Registry model: [Stinson 108-1](https://openairdocs.org/model/stinson-108-1) (registry code 9230404) (OpenAirDocs) - Registry engine: [Franklin 6A4150 series](https://openairdocs.org/engine/franklin-6a4150-series) (registry code 27024, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 108-1848 - Year built: 1947 - Airframe hours: 2280.3 - Engines: FRANKLIN 6A4-150-B3 150 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal; Standard, Utility - Last inspection: Annual, March 12, 2013 - Departed: O20, Lodi, CA - Destination: MOD, MODESTO, CA - Airport: O20, Kingdon Airpark ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 69; injuries: none; commercial; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; seat: left; flight hours: 1,200 total ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 4 statute miles - Lowest ceiling: none - Temperature: 48 °F, dew point 39 °F - Altimeter: 30.25 inHg - Observed at: SKC, 14 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 20131227025839A](https://openairdocs.org/incident/20131227025839A), Dec 27, 2013: Stinson 108-1, Lodi, CA, Substantial damage. Pilot in command (PIC) fueled up at medesto airport (30 gallons) and took off from medesto airport to Lodi airport without incident and landed safely at the… ## Docket (6 files) The files NTSB released with the investigation on November 19, 2014, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=88596. 3.0 MB in all. - Record of Conversation - Bryant (item 1, .PDF, 164 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40419158&FileExtension=.PDF&FileName=Record%20of%20Conversation%20-%20Bryant-Redacted.PDF - Airframe and Engine Examination (item 2, .PDF, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40419159&FileExtension=.PDF&FileName=Airframe%20and%20Engine%20Examination-Master.PDF - Pilot Statement to FAA (item 3, .PDF, 99 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40419160&FileExtension=.PDF&FileName=Pilot%20Statement%20to%20FAA-Redacted.PDF - Aircraft Records (item 4, .PDF, 883 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40419161&FileExtension=.PDF&FileName=Aircraft%20Records-Redacted.PDF - Release of Aircraft Wreckage, NTSB Form 6120.15 (item 5, .PDF, 116 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40419162&FileExtension=.PDF&FileName=Release%20of%20Aircraft%20Wreckage,%20NTSB%20Form%206120.15-Redacted.PDF - Materials Laboratory - Factual Report of Group Chairman (item 6, .PDF, 540 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40419163&FileExtension=.PDF&FileName=Materials%20Laboratory%20-%20Factual%20Report%20of%20Group%20Chairman-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.