# NTSB CEN17LA238: Aeronca 7BCM, N2558E, Mahnomen, MN, June 21, 2017 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: June 20, 2017, 20:00 local (Jun 21, 2017, 01:00 UTC) - Place: Mahnomen, MN - Coordinates: 47.267223, -95.92028 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=47.2672&lon=-95.9203&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report November 6, 2018 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA Fargo FSDO - NTSB case key (mKey): 95405 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN17LA238 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/95405/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=95405 - Page: https://openairdocs.org/ntsb/CEN17LA238 ## Probable cause The pilot’s failure to abort the takeoff after recognizing a partial loss of engine power during the takeoff roll and his subsequent inability to maintain adequate airspeed during a turn to avoid power lines, which resulted in an aerodynamic stall. The reasons for the loss of engine power could not be determined because postaccident examination of the engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Action: lack of action](https://openairdocs.org/ntsb-findings/02041030): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Aeronca 7BCM, 1 case](https://openairdocs.org/ntsb-findings/02041030/cases.md?model=2110106), [All aircraft, 792 cases](https://openairdocs.org/ntsb-findings/02041030/cases.md) - [Performance/control parameters: airspeed](https://openairdocs.org/ntsb-findings/01062010): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible (probable cause); cases with it: [Aeronca 7BCM, 3 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md?model=2110106), [All aircraft, 1,681 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Aeronca 7BCM, 11 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=2110106), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Aeronca 7BCM, 2 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=2110106), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot; cases with it: [Aeronca 7BCM, 3 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=2110106), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) - [Temp/humidity/pressure: conducive to carburetor icing](https://openairdocs.org/ntsb-findings/03031030): Environmental issues › Conditions/weather/phenomena · Not specified; cases with it: [Aeronca 7BCM, 1 case](https://openairdocs.org/ntsb-findings/03031030/cases.md?model=2110106), [All aircraft, 435 cases](https://openairdocs.org/ntsb-findings/03031030/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Aeronca 7BCM, 3 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=2110106), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Initial climb: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241); cases with it: [Aeronca 7BCM, 2 cases](https://openairdocs.org/ntsb-events/241/sequence.md?model=2110106), [All aircraft, 1,529 cases](https://openairdocs.org/ntsb-events/241/sequence.md) - [Initial climb: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Aeronca 7BCM, 10 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2110106), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The sport pilot reported that the initial takeoff roll was normal but that he then noted that the airplane was not gaining airspeed and that the engine was not developing full power; however, he decided to continue the takeoff. He stated that, once he was committed to the takeoff, there seemed to be an even "greater loss of power." The airplane only reached 150 ft, and he decided to turn right to avoid a highway and power lines. He initiated a 20° bank, and subsequently the airplane stalled and then impacted a bean field adjacent to the airport. Postaccident examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. Although weather conditions at the time of the accident were conducive to moderate icing at cruise power or serious carburetor icing at descent power, given the airplane was at takeoff power, it is unlikely that carburetor ice accumulated and caused the power loss. The pilot's decision to not abort the takeoff at the first sign of a loss of engine power resulted in a slow airspeed during the initial climb during a turn, which resulted in the aerodynamic stall. ## Factual narrative On June 20, 2017, about 2000 central daylight time, an Aeronca 7BCM airplane, N2558E, sustained substantial damage during initial climb from the Mahnomen County Airport (3N8), Mahnomen, Minnesota, when it impacted a bean field after a loss of control. The sport pilot was seriously injured. The airplane was owned and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which was not operated on a flight plan. The airplane was departing 3N8 on a local flight. The pilot reported that he had flown the airplane earlier in the day. About 1900, he returned to the airport with the intention of going on a short local flight. He preflighted the airplane, including fuel samples, and taxied to the run-up area where he performed the before take-off checklist items. He departed from runway 35 and the initial takeoff roll was normal. The pilot then noted the airplane was not gaining airspeed and the engine was not developing full power; but he decided to continue the takeoff. Once he was committed to the takeoff, there seemed to be an even "greater loss of power He stated that the airplane did not gain more than 150 ft of altitude. He stated, "The power seemed to still be fading and I was basically 'hanging on the prop' when I decided to initiate a very slight bank (20 degrees)" to avoid a highway and powerlines. He stated that the airplane stalled and impacted a bean field adjacent to the airport. Witnesses reported that the airplane appeared to be going slow and not climbing before the airplane banked to the right and impacted the ground in a nose down attitude. A Federal Aviation Administration inspector examined the airplane. He removed the valve covers and found a rusty valve springs. He stated that he was able to rotate the engine, and the crankshaft and drive train exhibited continuity. The magnetos turned and sparked. Fuel was found in the carburetor bowl. The spark plugs were normal in color and wear. The header fuel tank was ruptured. There was an auxiliary fuel tank in the left wing. The propeller exhibited minimal damage. He checked and confirmed flight control continuity. No preexisting anomalies to the engine and airframe were noted. In the NTSB accident report which the pilot completed, he provided two recommendations on how the accident could have been prevented: 1. "Aborting the takeoff at the first sign of any kind of performance issue…with enough runway to stop plane." 2. Keep the noise canceling headset turned off during takeoffs and landings. He stated, "Perhaps I would have reacted differently (aborted) if my ears told me the same thing as the controls and instruments referring to the increasing loss of power/thrust/lift." At 2015, the surface weather observation at 3N8 was: wind light and variable; visibility 10 miles; sky clear; temperature 20° C; dew point 8° C; altimeter 29.94 inches of mercury. According to the carburetoricing chart, weather conditions at the time of the accident were conducive to moderate icing at cruise power or serious carburetor icing at descent power. ## Aircraft - Registration: [N2558E](https://openairdocs.org/aircraft/N2558E), registered now, S/N 7AC-6141, built 1946 (OpenAirDocs) - Reported make and model: AERONCA 7BCM - Registry model: [Aeronca 7BCM](https://openairdocs.org/model/aeronca-7bcm) (registry code 2110106) (OpenAirDocs) - Registry engine: [Continental C85 series](https://openairdocs.org/engine/continental-c85-series) (registry code 17008, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 7AC-6141 - Year built: 1946 - Engines: Continental C-86-12F 85 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, September 18, 2016, 3,730 hours before - Departed: 3N8, Mahnomen, MN - Destination: 3N8, Mahnomen, MN - Airport: 3N8, Mahnomen County Airport, runway 35, 3,400 × 75 ft, asphalt - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 56; injuries: serious; sport pilot; airplane ratings: single-engine land; medical: sport pilot; seat: front; restraint: 4-point; flight hours: 168 total, 168 in this make and model, 143 as pilot in command, 27 in the last 90 days, 12 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 68 °F, dew point 46 °F - Altimeter: 29.94 inHg - Observed at: 3N8 ## 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 20170620009419A](https://openairdocs.org/incident/20170620009419A), Jun 20, 2017: Aeronca 7BCM, Mahnomen, MN, Destroyed. A 3.5 hour flight had taken place in the morning of 6/20/2017 with no issues observed. In the afternoon of 6/20/2017 the pilot, [privacy data omitted], decided… ## Docket (5 files) The files NTSB released with the investigation on April 16, 2018, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=95405. 5.2 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 3.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40461992&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Witness Statements (item 2, .PDF, 160 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40461993&FileExtension=.PDF&FileName=Witness%20Statements-Master.PDF - NTSB Record of Conversation (item 3, .PDF, 55 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40461994&FileExtension=.PDF&FileName=NTSB%20Record%20of%20Conversation-Master.PDF - Carburetor Icing Chart (item 4, .PDF, 107 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40461995&FileExtension=.PDF&FileName=Carburetor%20Icing%20Chart-Master.PDF - Investigation Photos (item 5, .PDF, 6 photos, 955 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40461996&FileExtension=.PDF&FileName=Investigation%20Photos-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.