# NTSB ERA20LA320: Stinson 108, N336C, Newport, PA, September 17, 2020 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 3 · Limited · Final report - Date: September 17, 2020, 12:54 local (16:54 UTC) - Place: Newport, PA - Coordinates: 40.519443, -77.166664 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=40.5194&lon=-77.1667&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: Approved by Office Director - Investigation class: Class 3 - NTSB office: Eastern Region Aviation - Parties: FAA/FSDO - NTSB case key (mKey): 101987 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA20LA320 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/101987/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=101987 - Page: https://openairdocs.org/ntsb/ERA20LA320 ## Probable cause A total loss of engine power during cruise flight due to a disconnected carburetor mixture control cable which allowed the carburetor mixture lever to migrate to the cut-off position during flight. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine fuel and control: fuel control/carburetor](https://openairdocs.org/ntsb-findings/01057322): Aircraft › Aircraft power plant · Malfunction (probable cause); cases with it: [Stinson 108-2, 2 cases](https://openairdocs.org/ntsb-findings/01057322/cases.md?model=9230406), [All aircraft, 195 cases](https://openairdocs.org/ntsb-findings/01057322/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [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) - [Enroute-cruise: 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) ## Analysis The flight instructor stated that he and the pilot fueled the airplane, departed, and flew for about 1.5 hours when, while cruising at 3,500 ft, the engine “started to sputter.” He checked the magnetos, adjusted the mixture, switched fuel tanks, and pumped the primer and throttle. When he pumped the primer, the engine would “run for about 5 seconds then quit,” and the propeller continued to windmill. Unable to restore power to the engine, he elected to execute a forced landing to a field. During the landing rollout, the airplane impacted a berm resulting in substantial damage to the fuselage. Postaccident examination of the engine revealed that although the cockpit mixture knob was set to full rich, the carburetor mixture control cable was disconnected at the carburetor and the carburetor mixture lever on the carburetor was in idle cutoff position. The hardware that would have attached these components was not located. Given this information, it is likely that hardware holding the mixture control cable to the mixture control arm loosened and departed during flight, allowing the disconnected mixture control arm to migrate to the cut-off position, resulting in a total loss of engine power. Since both the accelerator pump and the primer system bypass the carburetor and delivers some fuel directly to the engine even when the mixture control is in the “cutoff” position, this would explain why the instructor reported momentary bursts of power when he pumped the primer or throttle. ## Factual narrative On September 17, 2020, at 1254 eastern daylight time, a Stinson 108-2 airplane, N336C, was substantially damaged when it was involved in an accident near Newport, Pennsylvania. The flight instructor sustained minor injuries and the pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. According to the flight instructor, he and the pilot fueled the airplane, departed, and flew for about 1.5 hours when, while cruising at 3,500 ft, the engine “started to sputter.” He checked the magnetos, adjusted the mixture, switched fuel tanks, and pumped the primer and throttle. When he pumped the primer, the engine would “run for about 5 seconds then quit,” and the propeller continued to windmill. Unable to restore power to the engine, he elected to execute a forced landing to a field. During the landing rollout, the airplane impacted a berm. Examination of the airplane by a Federal Aviation Administration (FAA) inspector revealed that it was intact and came to rest upright. The main landing gear collapsed, and the firewall and forward fuselage were impact damaged. One propeller was bent aft and exhibited chordwise scratching. The inspector noted fuel in both wing tanks and the fuel appeared absent of water and debris. The cockpit mixture control was selected to full rich (IN). The engine and its accessories were examined under the supervision of an FAA inspector in the field at the accident site, and again after the airplane was recovered to a hangar. The spark plugs were removed and visually examined with no anomalies noted. Both magnetos were present and securely installed and connected. The magneto to engine timing was within specifications and both magnetos produced spark at all towers when rotating the engine by hand. Rotation of the engine’s crankshaft produced compression on all cylinders, and normal valvetrain movement was observed when the crankshaft was rotated. Fuel was present throughout the fuel system and was absent of water and debris. Fuel was also present in the gascolator and the carburetor float bowl. Air was blown through the fuel cap vent tubes to the carburetor fuel supply hose and the vents and fuel lines were found to be free of obstruction. The carburetor screen was free from obstruction. The carburetor mixture control cable was found disconnected at the carburetor. The carburetor mixture lever on the carburetor was found in idle cutoff position. The attaching hardware that would have connected the mixture control cable connector fitting to the carburetor mixture arm was not located. ## Aircraft - Registration: [N336C](https://openairdocs.org/aircraft/N336C), registered now, S/N 108-3336 (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: 108-3336 - Year built: 1947 - Airframe hours: 2691 - Engines: Franklin 6A4-165-B4 165 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Airworthiness certificate: Standard, Utility; Standard, Normal - Last inspection: Annual, December 1, 2019 - Departed: VVS, Connellsville, PA - Destination: 1N7, Blairstown, NJ - Airport: NONE - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 72; injuries: none; flight instructor, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review June 1, 2019; seat: right; restraint: lap only; flight hours: 15,000 total, 30 in this make and model, 50 in the last 90 days, 18 in the last 30 days, 5 in the last 24 hours - Pilot; age 32; injuries: none; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; seat: left; restraint: lap only; flight hours: 66 total, 1 in this make and model, 20 as pilot in command, 4 in the last 90 days, 4 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 9 statute miles - Lowest ceiling: none - Temperature: 72 °F, dew point 59 °F - Altimeter: 30.03 inHg - Observed at: RVL, 23 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 20200917019329A](https://openairdocs.org/incident/20200917019329A), Sep 17, 2020: Stinson 108-2, Newport, PA, Substantial damage. On 9-17-20 at around 12:15 local, a Stinson 108, NC336C lost engine power inflight near Newport, PA. The aircraft was substantially damaged during the forced… ## Docket (9 files) The files NTSB released with the investigation on September 13, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=101987. 17.3 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 6.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11555705&FileExtension=pdf&FileName=ERA20LA320%206120_Redacted-Rel.pdf - Witness statements (item 2, PDF, 4 pages, 97 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11554963&FileExtension=pdf&FileName=Witness%20Statements-Rel.pdf - FAA inspector's statement (item 3, PDF, 1 page, 55 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11555068&FileExtension=pdf&FileName=Record%20of%20Conversation%20FAA%20ASI-Rel.pdf - Maintenance log excerpts (item 4, PDF, 4 pages, 3.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11557482&FileExtension=pdf&FileName=Maintenance%20Log%20Excerpts_Redacted-Rel.pdf - Area weather reports (item 5, PDF, 1 page, 80 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11555078&FileExtension=pdf&FileName=Area%20Weather%20Reports-Rel.pdf - Investigative photographs (item 6, PDF, 6 pages, 3.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11555338&FileExtension=pdf&FileName=ERA20LA320%20Photo%20Array-Rel.pdf - Memorandum for record a�� wreckage examination 1 (item 7, PDF, 3 pages, 229 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11555866&FileExtension=pdf&FileName=Engine%20Exam%201%20Notes-Rel.pdf - Memorandum for record a�� wreckage examination 2 (item 8, PDF, 4 pages, 573 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11557139&FileExtension=pdf&FileName=Engine%20Exam%202%20Notes-Rel.pdf - Release of aircraft wreckage, NTSB form 6120.15 (item 9, PDF, 1 page, 3.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11554820&FileExtension=pdf&FileName=Signed%20Wreckage%20Release%20Package_Redacted-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.