# NTSB ERA23LA360: Brown Benjamin C Challenger II, N2480Y, Moultonborough, NH, September 1, 2023 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: September 1, 2023, 09:10 local (13:10 UTC) - Place: Moultonborough, NH - Coordinates: 43.755385, -71.418589 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.7554&lon=-71.4186&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: No injuries - Injuries: 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): 192999 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA23LA360 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/192999/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=192999 - Page: https://openairdocs.org/ntsb/ERA23LA360 ## Probable cause A loss of engine power due to a loss of compression in one of the engine’s two cylinders. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine fuel and control](https://openairdocs.org/ntsb-findings/01057300): Aircraft › Aircraft power plant · Incorrect service/maintenance (probable cause); cases with it: [Brown Benjamin C CHALLENGER II, 1 case](https://openairdocs.org/ntsb-findings/01057300/cases.md?model=0590207), [All aircraft, 49 cases](https://openairdocs.org/ntsb-findings/01057300/cases.md) - [Action: incorrect action performance](https://openairdocs.org/ntsb-findings/02041015): Personnel issues › Action/decision · Maintenance personnel; cases with it: [Brown Benjamin C CHALLENGER II, 1 case](https://openairdocs.org/ntsb-findings/02041015/cases.md?model=0590207), [All aircraft, 1,386 cases](https://openairdocs.org/ntsb-findings/02041015/cases.md) - [Aircraft](https://openairdocs.org/ntsb-findings/01050000): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Brown Benjamin C CHALLENGER II, 1 case](https://openairdocs.org/ntsb-findings/01050000/cases.md?model=0590207), [All aircraft, 151 cases](https://openairdocs.org/ntsb-findings/01050000/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 (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Brown Benjamin C CHALLENGER II, 1 case](https://openairdocs.org/ntsb-events/341/sequence.md?model=0590207), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Landing: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Brown Benjamin C CHALLENGER II, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=0590207), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-landing roll: Collision during takeoff/land](https://openairdocs.org/ntsb-events/490); cases with it: [Brown Benjamin C CHALLENGER II, 1 case](https://openairdocs.org/ntsb-events/490/sequence.md?model=0590207), [All aircraft, 1,309 cases](https://openairdocs.org/ntsb-events/490/sequence.md) ## Analysis The pilot reported that a few minutes after takeoff, during the initial climb, the airplane’s two-stroke engine began to slowly lose power. The pilot attempted to restart the engine but was unsuccessful. He elected to make a forced landing in small field, resulting in substantial damage to both of the airplane’s wing struts. Postaccident examination of the engine revealed that one of the engine’s two cylinders had no compression. It is likely that this lack of compression resulted in the loss of engine power reported by the pilot during the accident flight. Additionally, during the examination, a zip tie was found secured around the fuel line that provided fuel for that cylinder in a way that reduced its interior diameter. It is possible that the reduced diameter of the fuel line could have resulted in less fuel reaching the cylinder during high power operation, and that it was operating in an excessively lean condition. Operation in this state could have damaged the cylinder and resulted in the lack of compression observed during the engine examination. It could not be determined when the zip-tie was installed on the fuel line, though entries in the airplane’s maintenance logs indicated that its last condition inspection was completed about three months before the accident. ## Factual narrative On September 1, 2023, at 0910 eastern daylight time, an experimental amateur-built Challenger II, N2480Y, was substantially damaged when it was involved in an accident near Moultonborough, New Hampshire. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot, during takeoff and initial climb, the engine was producing full power without anomalies. Then, while still in the climb, the engine gradually sustained a total loss of power. The pilot attempted to make two engine restarts but was unsuccessful. The pilot performed a forced landing in a field, resulting in substantial damage to both left and right wing struts. A postaccident examination of the two-cylinder, two-stroke engine found that the airplane contained between 7 and 10 gallons of fuel with no contamination. There was evidence of spark from all of the ignition leads, and all four spark plugs were gapped within recommended specifications. The engine’s crankshaft rotated when force was applied to the propeller with no discrepancies noted. The engine contained adequate oil. The cylinders were checked for compression and the cylinder closest to the magneto had no compression. A fuel line leading to the cylinder was found with a zip-tie secured to it that reduced the interior circumference of the fuel line. According to the airplane’s maintenance logbooks, the fuel lines were installed in March 2013 and inspected in June 2019. A condition inspection of the engine was completed in June 2023, with a total time of 564.7 hours. It is unknown when the zip-tie was placed around the fuel line. ## Aircraft - Registration: [N2480Y](https://openairdocs.org/aircraft/N2480Y), registered now, S/N CH20394-4139, built 1996 (OpenAirDocs) - Reported make and model: BROWN BENJAMIN C CHALLENGER II - Registry model: [Brown Benjamin C CHALLENGER II](https://openairdocs.org/model/brown-benjamin-c-challenger-ii) (registry code 0590207) (OpenAirDocs) - Registry engine: [Rotax 503 DCDI](https://openairdocs.org/engine/rotax-503-dcdi) (registry code 55566, 2 cycle) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: CH20394-4139 - Year built: 1996 - Engines: Rotax 503 DCI reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental light sport (Special) - Airport: 4MB, Moultonborough ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 74; injuries: none; private; airplane ratings: single-engine land; medical: class 3; flight hours: 410 total, 0 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 220° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 57 °F, dew point 52 °F - Altimeter: 30.29 inHg - Observed at: LCI, 11 nm away - METAR: KLCI 011256Z AUTO 22005KT 10SM CLR 14/11 A3029 RMK AO2 SLP255 T01440106 ## 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 20230901015639A](https://openairdocs.org/incident/20230901015639A), Sep 1, 2023: Brown Benjamin C CHALLENGER II, Moultonborough, NH, Substantial damage. Pilot stated the aircraft produced normal takeoff power and departed the runway without issue but shortly after departing runway 22 at 4MB the engine slowly… ## Docket (4 files) The files NTSB released with the investigation on April 1, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=192999. 2.6 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 1 page, 63 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17454406&FileExtension=pdf&FileName=01_ERA23LA360%206120%20Attempts-Rel.pdf - Maintenance records (item 2, PDF, 4 pages, 296 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17453690&FileExtension=pdf&FileName=03_ERA23LA360%20Log%20Book%20Entries_Redacted-Rel.pdf - FAA inspector's statement (item 3, PDF, 2 pages, 70 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17456996&FileExtension=pdf&FileName=04_ERA23LA360%20FAA%20Email%20ROC-Rel.pdf - Investigative photographs (item 4, PDF, 6 pages, 2.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17454056&FileExtension=pdf&FileName=06_ERA23LA360%20Photo%20Array-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.