# NTSB CHI98LA334: Culver-Revolution Mini 500, N6269R, Eden Prairie, MN, September 9, 1998 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: September 8, 1998, 19:00 local (Sep 9, 1998, 00:00 UTC) - Place: Eden Prairie, MN - Coordinates: 44.919227, -93.40068 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=44.9192&lon=-93.4007&mi=10 - Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report May 19, 1999 - Report: Approved by Office Director - NTSB case key (mKey): 43843 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI98LA334 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/43843/pdf - Page: https://openairdocs.org/ntsb/CHI98LA334 ## Probable cause a design change to the fuel tank filler neck sealant made by the owner/builder of the helicopter. Factors associated with this accident were an improper sealant material used by the owner/builder and an autorotation was not possible by the pilot due to the hover-taxis low altitude. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power(total) - nonmechanical, taxi - aerial - fuel system,filter - blocked(total) - maintenance,design change - performed, owner/builder (cause) - material inadequate,improper, owner/builder (contributing factor) - fuel system,filter - foreign material/substance - spiral - not possible, pilot in command (contributing factor) - fluid,fuel - starvation - In flight collision with terrain/water, descent - uncontrolled - terrain condition - ground - Roll over, other ## Analysis The kit-built helicopter was hover-taxiing for about ten minutes according to the pilot/builder. He said '...the engine stopped unexpectedly [and the helicopter] settled to the runway and rolled over.' The on-scene investigation revealed a silicon-type sealant had completely blocked the supply side of the fuel filter. The builder said he had used this material to seal the fuel tank filler neck's flange to the fuel tank. According to the manufacturer's instruction manual, the builder is to 'Place a 1/8-inch bead of MA300 from the adhesive kit around [the] hole circle through the centerline of [the mounting] holes.' MA300 is an epoxy-type glue/sealant that does not break down when contacted by gasoline. The silicon-type material dissolves when it comes in contact with gasoline, according to the helicopter's kit manufacturer. ## Factual narrative On September 8, 1998, at 1900 central daylight time (cdt), a Culver-Revolution Mini 500, N6269R, piloted by a private pilot, was substantially damaged when it collided with the ground shortly after a total loss of power while hovering. Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 91 personal flight was not operating on a flight plan. The pilot reported no injuries. The flight departed Eden Prairie, Minnesota, at 1850 cdt. The pilot said he had been hover-taxiing the helicopter between the approach end of runway 36 and the south taxiway for runway 09R. He said he had been hover-taxiing for about 10-minutes when "...the engine stopped unexpectedly [and it] settled to the runway and rolled over." The on-scene investigation revealed no anomalies with the airframe, engine or control system that would prevent flight. Examination of the fuel system revealed a silicon-type sealant had completely blocked the supply side of the fuel filter. According to the pilot/builder, he had used this material as a seal between the helicopter's fuel tank filler neck flange and fuel tank body. The helicopter's kit manufacturers instruction states that the builder is to "Place a 1/8-inch bead of MA300 from the adhesive kit around [the] hole circle through the centerline of [the mounting] holes." A copy of these instructions are appended to this report. The kit manufacturer was contacted regarding the accident and pilot/builders use of the silicon-type material. The manufacturer representative was asked if there were any warnings in the construction manual against the use of the silicon-type sealant as the builder had done. He said there were no warnings, only instructions to use the MA300 material. He said the MA300 is an epoxy- type glue/sealant that does not break down when contacted by gasoline. He said the silicon-type sealant will dissolve when contacted by gasoline. The IIC suggested the company publish a manual change or communicate the need to use only the sealant recommended by them. The company representative agreed and said they would put a notice in the next builder's newsletter. A copy of the company's December 1998 newsletter is appended to this report. ## Aircraft - Registration: [N6269R](https://openairdocs.org/deregistered/N6269R-2017-02-28), registration cancelled 2017-02-28, S/N 376, built 1998 (OpenAirDocs) - Reported make and model: Culver-Revolution MINI 500 - Registry model: [Culver Randy N REVOLUTION MINI 500](https://openairdocs.org/model/culver-randy-n-revolution-mini-500) (registry code 056050P) (OpenAirDocs) - Registry engine: [Bombardier ROTAX (ALL)](https://openairdocs.org/engine/bombardier-rotax-all) (registry code 09050, reciprocating) (OpenAirDocs) - Category: Helicopter, amateur-built - Serial number: 376 - Airframe hours: 9 - Engines: Rotax 582 80 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Randy N. Culver - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, July 9, 1998, 4 hours before - Departed: FCM - Destination: FCM - Airport: FCM, Flying Cloud ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 43; private; medical: class 3, valid medical--no waivers/lim.; seat: center; flight hours: 119 total, 9 in this make and model, 59 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 140° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 68 °F, dew point 45 °F - Altimeter: 30.00 inHg - Observed at: FCM, 1 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 19980908022609A](https://openairdocs.org/incident/19980908022609A), Sep 8, 1998: Amtr MINI500, Minneapolis, MN, Substantial damage. Helicopter was hovering over the approach end of rwy 36 when it lost power and crashed.(-23) aircraft was transitioning from hover to forward flight at… 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.