# NTSB ERA21LA109: Plante Challenger II, N4469Z, Minneola, FL, January 21, 2021 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Class 3 · Limited · Final report - Date: January 21, 2021, 09:45 local (14:45 UTC) - Place: Minneola, FL · 123 degrees and 1,087 ft from the center of 3FD4 - Coordinates: 28.62612, -81.80011 - Nearby events: https://openairdocs.org/map.md?lat=28.6261&lon=-81.8001&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach-VFR pattern final: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Eastern Region Aviation - Parties: FAA/FSDO - NTSB case key (mKey): 102543 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA21LA109 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/102543/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=102543 - Page: https://openairdocs.org/ntsb/ERA21LA109 ## Probable cause Failure of the engine/propeller drive belt. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating): recip engine power section](https://openairdocs.org/ntsb-findings/01058520): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Plante Matthew L CHALLENGER II, 1 case](https://openairdocs.org/ntsb-findings/01058520/cases.md?model=05625OC), [All aircraft, 233 cases](https://openairdocs.org/ntsb-findings/01058520/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach-VFR pattern final: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340) (defining event); cases with it: [Plante Matthew L CHALLENGER II, 1 case](https://openairdocs.org/ntsb-events/340/sequence.md?model=05625OC), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md) - [Emergency descent: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241); cases with it: [Plante Matthew L CHALLENGER II, 1 case](https://openairdocs.org/ntsb-events/241/sequence.md?model=05625OC), [All aircraft, 1,529 cases](https://openairdocs.org/ntsb-events/241/sequence.md) ## Analysis The pilot of the experimental amateur-built airplane stated that he was on final approach when the airplane “abruptly” turned right 45°, and the flight controls no longer felt normal. The pilot said it was a challenge to maneuver the airplane and, as he attempted to avoid trees, the airplane stalled and impacted the ground. A postaccident examination of the airplane and its two-stroke engine revealed that the belt that connected the engine output sprocket to the propeller drive sprocket had broken. The belt had not been manufactured for use in aircraft. Examination of the edges of the belt revealed that it appeared rubbed with exposed core strands in several areas consistent with lateral travel or tracking and that the belt ultimately broke due to tensile overload failure. ## Factual narrative On January 21, 2021, about 0945 eastern standard time, an experimental amateur-built Challenger II, N4469Z, was substantially damaged when it was involved in an accident near the Florida Flying Gators Ultralight Airport (3FD4), Minneola, Florida. The student pilot/owner was seriously injured. The airplane was operating as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot stated that he was on final approach when the airplane “abruptly” turned right 45° and the flight controls no longer felt normal. He added power to go around and immediately decided it was best to make a forced landing in a field east of the airport, and reduced power. The pilot said it was a challenge to maneuver the airplane and, in an attempt, to avoid trees, the airplane stalled. It then impacted terrain, resulting in substantial damage to the fuselage and both wings. A postaccident examination of the airplane and its two-stroke engine revealed that the belt that connected the engine output sprocket to the propeller drive sprocket was broken and laying across the empennage. Detailed examination of the belt revealed that it had a transverse fracture that intersected a tooth root at the interior side and had a more jagged transverse path through the glass reinforcement core strands, features consistent with a tensile overload failure. The edges of the belt appeared rubbed with exposed core strands in several areas consistent with lateral travel or tracking. The interior surfaces of the drive belt generally appeared free of significant wear, though fiber damage was observed on the interior surface where the tooth peaks were damaged on approximately 12 of the 120 total teeth. The pilot purchased the airplane in October 2020. He said that the previous owner had installed the belt. The pilot estimated the belt had accrued about 70 hours when it failed. Markings on the exterior surface of the belt indicated the belt was a PowerGrip GT3 960-8MGT-50 synchronous belt manufactured by the Gates Corporation. The Gates PowerGrip GT3 Drive Design Manual includes a “Safety Policy” for primary in-flight aircraft systems that states, “Do not use Gates belts, pulleys or sprockets on aircraft, propeller or rotor drive systems or in-flight accessory drives. Gates belt drive systems are not intended for aircraft use.” In June 2015, the Federal Aviation Administration (FAA) issued an InFO (Information for Operators) bulletin (No. 15007), titled Gates Products Not Designed or Intended for Aircraft Use. It stated: Operators and repair facilities should familiarize themselves with the information contained within this InFO and with Gates Catalog Aircraft Policy in order to be aware of and reduce the risk of accidents caused by belts not intended for aircraft use. However, if Gates products are used, operators and repair facilities should be aware of main drive belt breaks on aircraft utilizing a hydraulic cog belt tensioner and the proper measurement of tension when thetensioner reaches the desired parameters and also adhere to the manufacturers recommended life limits and inspection cycles. ## Aircraft - Registration: [N4469Z](https://openairdocs.org/aircraft/N4469Z), registered now, S/N CH2-1007-2821 (OpenAirDocs) - Reported make and model: Plante Challenger II (NO SERIES) - Registry model: [Plante Matthew L CHALLENGER II](https://openairdocs.org/model/plante-matthew-l-challenger-ii) (registry code 05625OC) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: CH2-1007-2821 - Year built: 2008 - Airframe hours: 435 - Engines: Rotax 503 DCD1 52 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Condition, November 21, 2020 - Departed: 06FD, Mascotte, FL - Destination: Same as departure - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 55; injuries: serious; student; seat: left; restraint: 4-point; flight hours: 39.4 total, 12.4 in this make and model, 13 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 260° at 9 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 70 °F, dew point 54 °F - Altimeter: 30.15 inHg - Observed at: ORL, 25 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 20210121003259A](https://openairdocs.org/incident/20210121003259A), Jan 21, 2021: Plante Matthew L CHALLENGER II, Minneola, FL, Substantial damage. On approach to Florida Flying Gators Airport the aircraft crashed in a pasture approximately one quarter of a mile from the airport. The pilot sustained… ## Docket (5 files) The files NTSB released with the investigation on October 12, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=102543. 3.7 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 629 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13022141&FileExtension=pdf&FileName=NTSB%20%20Accident%20Report_Redacted-Rel.pdf - Photos (item 2, PDF, 5 pages, 5 photos, 1.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13021940&FileExtension=pdf&FileName=Photo%20Array-Rel.pdf - Engine logbook (item 3, PDF, 6 pages, 299 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13021950&FileExtension=pdf&FileName=Engine%20Log_Redacted-Rel.pdf - Materials laboratory factual report 21-052 (item 4, PDF, 4 pages, 6 photos, 703 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12579529&FileExtension=pdf&FileName=21-052-Rel.pdf - FAA bulletin (item 5, PDF, 2 pages, 94 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14568824&FileExtension=pdf&FileName=FAA%20Info%20Bulletin%2015007-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.