# NTSB WPR09LA382: Stinson 108-2, N373C, Salt Lake City, UT, August 3, 2009 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: August 3, 2009, 13:15 local (19:15 UTC) - Place: Salt Lake City, UT - Coordinates: 40.76139, -111.971107 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=40.7614&lon=-111.9711&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: Minor injuries - Injuries: 1 minor, 1 uninjured - Status: Completed, report December 15, 2009 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 74438 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR09LA382 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/74438/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=74438 - Page: https://openairdocs.org/ntsb/WPR09LA382 ## Probable cause A total loss of engine power during cruise flight due to the failure of the crankshaft gear. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating): recip eng rear section](https://openairdocs.org/ntsb-findings/01058540): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Stinson 108-2, 1 case](https://openairdocs.org/ntsb-findings/01058540/cases.md?model=9230406), [All aircraft, 42 cases](https://openairdocs.org/ntsb-findings/01058540/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340); cases with it: [Stinson 108-2, 1 case](https://openairdocs.org/ntsb-events/340/sequence.md?model=9230406), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) - [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Stinson 108-2, 5 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=9230406), [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: [Stinson 108-2, 5 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=9230406), [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: [Stinson 108-2, 9 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=9230406), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis During cruise flight, the pilot experienced a complete loss of engine power and initiated a forced landing to an open field. During the landing roll, the airplane encountered a ditch, which resulted in substantial damage to the airplane's fuselage. A Federal Aviation Administration airworthiness inspector reported damage to the accessory section of the engine. A subsequent postaccident examination of the engine by a second inspector revealed that the crankshaft gear had failed, which resulted in significant damage to all the gears in the accessory section of the engine. Over 50 percent of the crankshaft gear could not be found, and the crankshaft gear appeared to have fractured and failed through both dowel pin slots. The engine was manufactured in 1947 and was the original engine installed by the factory at the time of the airframe's manufacture. The engine had accumulated 2,520 hours time in service and was overhauled 147 hours prior to the accident. ## Factual narrative On August 3, 2009, about 1315 mountain daylight time, a Stinson 108-2, N373C, sustained substantial damage after making a forced landing due to a total loss of engine power about 2 miles east of the Salt Lake City International Airport (SLC), Salt Lake City, Utah. The commercial pilot was not injured, and the sole passenger sustained minor injuries. Visual meteorological conditions prevailed for the cross-country flight, which was operated in accordance with Title 14 Code of Federal Regulations (CFR) Part 91, and a flight plan was not filed. The flight departed the Rock Springs-Sweetwater County Airport (RKS), Rock Springs, Wyoming, about 1130, and was destined for the Bolinder Field-Tooele Valley Airport (TVY), Tooele, Utah. The pilot reported that while in cruise flight at 10,500 feet mean sea level (msl) "…the engine suffered a catastrophic failure." The pilot stated that he set up a glide for SLC, but seeing he was not going to make it he elected to land in an field east of the airport. The airplane sustained substantial damage to the fuselage in the area where both main landing gear were attached. A Federal Aviation Administration (FAA) airworthiness inspector, who responded to the accident site, reported damage to the accessory section of the Franklin 6A4-165 engine. A subsequent post-accident examination of the engine by a second inspector revealed that the crankshaft gear had failed, which resulted in the damage to the accessory section of the engine. The inspector further reported that all accessory gears exhibited mechanical damage. Over 50 percent of the crankshaft gear could not be found, and that the crankshaft gear appeared to have failed at both dowel pins slots. The engine was a Franklin 6A4-165B-3 that was manufactured in 1947 and was the original engine installed by the Stinson factory at the time of the airframe manufacture. The engine had accumulated 2,520 hours time in service and was overhauled 147 hours prior to the accident. ## Aircraft - Registration: [N373C](https://openairdocs.org/deregistered/N373C-2014-10-02), registration cancelled 2014-10-02, S/N 108-3373, built 1947 (OpenAirDocs) - Reported make and model: STINSON 108-2 - Registry model: [Stinson 108-2](https://openairdocs.org/model/stinson-108-2) (registry code 9230406) (OpenAirDocs) - Registry engine: [Franklin 6A4165 series](https://openairdocs.org/engine/franklin-6a4165-series) (registry code 27025, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 108-3373 - Airframe hours: 2520 - Engines: Franklin 6A4-165 B-3 165 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Charles R. McDermott - Registered owner: Honey S. McDermott - Airworthiness certificate: Standard, Normal - Last inspection: Annual, January 7, 2009, 53 hours before - Departed: RKS, Rock Springs, WY - Destination: TVY, Tooele, UT ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 62; injuries: none; commercial; airplane ratings: single-engine land; medical: class 2, with waivers/limitations; last flight review June 22, 2008; seat: left; flight hours: 1,992 total, 1,992 as pilot in command, 53 in the last 90 days, 253 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 160° at 9 knots - Visibility: 10 statute miles - Lowest ceiling: 20,000 ft broken - Temperature: 93 °F, dew point 34 °F - Altimeter: 30.03 inHg - Observed at: SLC, 2 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 20090803014429A](https://openairdocs.org/incident/20090803014429A), Aug 3, 2009: Univar 1082, Salt Lake City, UT, Substantial damage. (-23) The engine quite running so the pilot landed in a field one mile east of slc airport. The aircraft went through deep ditch which folded the gear back. It… ## Docket (2 files) The files NTSB released with the investigation on October 13, 2009, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=74438. 833 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 786 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40319317&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Record of Engine Examination Report (item 2, .PDF, 47 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40319318&FileExtension=.PDF&FileName=Record%20of%20Engine%20Examination%20Report-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.