# NTSB CEN19LA281: Stinson 108, N647C, Grand Rapids, MN, August 21, 2019 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 3 · Limited · Final report - Date: August 21, 2019, 13:38 local (18:38 UTC) - Place: Grand Rapids, MN - Coordinates: 47.209167, -93.510002 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=47.2092&lon=-93.5100&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: Central Region - Parties: FAA Flight Standards - NTSB case key (mKey): 100112 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN19LA281 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/100112/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=100112 - Page: https://openairdocs.org/ntsb/CEN19LA281 ## Probable cause A loss of engine power after takeoff for undetermined reasons. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Stinson 108-3, 3 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=9230408), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342); cases with it: [Stinson 108-3, 6 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=9230408), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [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) - [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Stinson 108-3, 5 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=9230408), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) ## Analysis The pilot reported that he allowed the engine to warm-up for about 15 minutes before takeoff and used the carburetor heat. The takeoff was normal, but shortly after establishing climb power, he noticed a reduction in power although the engine was still running smoothly. He turned to a left downwind for landing; however, "several seconds" later, the engine "popped twice and quit completely." The propeller was windmilling. The pilot executed a forced landing and the airplane sustained substantial damage to the aft fuselage, left wing, left horizontal stabilizer, and right float. Postaccident examination of the engine, including a test run, did not reveal any anomalies that would preclude normal operation. Although the weather conditions at the time of the accident were conducive to carburetor icing at glide power, the pilot reported that he used carburetor heat when the airplane was idling on the ground and that the airplane was operating at a high power setting when the engine lost power, both of which would have prevented the accumulation of carburetor ice. Thus, the reason for the loss of engine power could not be determined based on the available information and postaccident examination and testing. ## Factual narrative On August 21, 2019, about 1338 central daylight time, a float-equipped Stinson 108-3 airplane, N647C, was substantially damaged during a forced landing following a loss of engine power near Grand Rapids, Minnesota. The pilot had departed from Lily Lake located immediately north of the Grand Rapids/Itasca County Airport (GPZ) shortly before the accident. The pilot sustained minor injuries. The airplane was registered to a private individual and operated by the pilot as a Title 14 Code of Federal Regulations Part 91 personal flight. Visual meteorological conditions prevailed, and the flight was not operated on a flight plan. The local flight was originating at the time of the accident. The pilot reported that he allowed the engine to warm-up for about 15 minutes before takeoff. He used the carburetor heat during the run-up and before takeoff. The subsequent takeoff was normal. Shortly after establishing climb power, he noticed a reduction in power; although, the engine was still running smoothly. He turned to a left downwind for landing on Lily Lake. "Several seconds" later, the engine "popped twice and quit completely." The propeller continued to windmill. The airplane did not have enough altitude to land at the lake and the pilot executed a forced landing to a grass area near the water treatment plant northeast of the airport. A postaccident examination revealed that the airframe exhibited damage to the aft fuselage, left wing, left horizontal stabilizer, and right float. The right wing appeared intact with exception of minor deformation at the wing tip. The left-wing fuel tank was dislocated from the wing. The grass was blighted at the location the fuel tank came to rest consistent with a fuel exposure. The right-wing fuel tank appeared intact and about 20 gallons of fuel was recovered from that tank. The engine remained securely attached to the engine mount. The examination did not reveal any anomalies with respect to the engine, engine accessories, or related airframe components. An engine test run was conducted. The engine started without difficulty on the first attempt and ran smoothly. Magneto and carburetor heat checks were normal. The engine oil pressure remained within normal operating limits during the run. No anomalies consistent with an inability to produce rated power were observed. According to documentation issued by the Federal Aviation Administration, the possibility of carburetor icing at glide power existed at the time of the accident. ## Aircraft - Registration: [N647C](https://openairdocs.org/deregistered/N647C-2022-06-04), registration cancelled 2022-06-04, S/N 108-3647, built 1947 (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: [Continental O-470R](https://openairdocs.org/engine/continental-o-470r) (registry code 17071, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 108-3647 - Year built: 1947 - Airframe hours: 3892 - Engines: Continental O-470-R 230 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, July 29, 2019, 0 hours before - Departed: KGPZ, Grand Rapids, MN - Destination: KGPZ, Grand Rapids, MN - Airport: KGPZ, Grand Rapids/Itasca County - Equipment: Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 68; injuries: minor; flight instructor, commercial; airplane ratings: single-engine sea, single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review May 21, 2019; seat: left; restraint: 4-point; flight hours: 19,230 total, 38 in this make and model, 18,190 as pilot in command, 75 in the last 90 days, 35 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 300° at 11 knots - Visibility: 10 statute miles - Lowest ceiling: 6,500 ft overcast - Temperature: 66 °F, dew point 46 °F - Altimeter: 30.07 inHg - Observed at: GPZ ## 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 20190821013879A](https://openairdocs.org/incident/20190821013879A), Aug 21, 2019: Stinson 108-3, Grand Rapids, MN, Substantial damage. N647C departed lily lake, amphibious runway located on kgpz, Grand Rapids Airport. Pic's intent was to fly 4 miles to the south and practice landings on lake… ## Docket (6 files) The files NTSB released with the investigation on October 28, 2019, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=100112. 1.9 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40477225&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Summary of Aircraft Examination (item 2, .PDF, 32 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40477226&FileExtension=.PDF&FileName=Summary%20of%20Aircraft%20Examination-Master.PDF - Conversation Summary - Airways Aviation (item 3, .PDF, 56 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40477227&FileExtension=.PDF&FileName=Conversation%20Summary%20-%20Airways%20Aviation-Master.PDF - Conversation Summary - Grand Rapids Airport (item 4, .PDF, 55 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40477228&FileExtension=.PDF&FileName=Conversation%20Summary%20-%20Grand%20Rapids%20Airport-Master.PDF - Maintenance Records - Annual Inspection (item 5, .PDF, 226 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40477229&FileExtension=.PDF&FileName=Maintenance%20Records%20-%20Annual%20Inspection-Master.PDF - FAA Information Bulletin - Carburetor Icing Prevention (item 6, .PDF, 111 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40477230&FileExtension=.PDF&FileName=FAA%20Information%20Bulletin%20-%20Carburetor%20Icing%20Prevention-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.