# NTSB CHI87DEC05: Willi/Bensen B-8M, N2469, Fraser, MI, September 25, 1987

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Final report
- Date: September 25, 1987, 17:00 local (21:00 UTC)
- Place: Fraser, MI
- Coordinates: 42.529319, -82.939399 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=42.5293&lon=-82.9394&mi=10
- Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report December 10, 1990
- Report: Approved by Office Director
- NTSB case key (mKey): 13549
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI87DEC05
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/13549/pdf
- Page: https://openairdocs.org/ntsb/CHI87DEC05

## Probable cause

DETERIORATION OF THE INTERNAL SURFACE OF THE FUEL TANK WHICH LED TO BLOCKAGE OF THE FUEL FLOW AND SUBSEQUENT FUEL STARVATION OF THE ENGINE.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Loss of engine power(total) - mech failure/malf, takeoff
  - fuel system,tank - deteriorated (cause)
  - inadequate quality control, production/design personnel (cause)
  - fuel system,primer system - blocked(total) (cause)
  - fluid,fuel - starvation (cause)
- Forced landing, landing
- In flight collision with terrain/water, landing - flare/touchdown

## Analysis

AS THE STUDENT PILOT WAS TAKING OFF IN HIS EXPERIMENTAL HOME BUILT GYROPLANE, THE ENGINE LOST POWER, SHORTLY AFTER LIFT-OFF. SUBSEQUENTLY, THE GYROPLANE WAS DAMAGED DURING AN EMERGENCY LANDING. AN EXAM OF THE FUEL SYSTEM REVEALED THAT TANK SEALER HAD DETERIORATED ON THE INSIDE OF THE SEAT TANK & HAD DROPPED IN THE FUEL. SUBSEQUENTLY, A CHECK VALVE FOR A RUBBER HAND BULB (USED TO PRIME THE FUEL PUMPS) HAD BECOME STUCK. THIS RESULTED IN BLOCKAGE OF FUEL TO THE ENGINE.

## Aircraft

- Registration: [N2469](https://openairdocs.org/deregistered/N2469-2013-07-02), registration cancelled 2013-07-02, S/N 86, built 1986 (OpenAirDocs)
- Reported make and model: WILLI/BENSEN B-8M
- Registry model: [Willi Don E B8M](https://openairdocs.org/model/willi-don-e-b8m) (registry code 13021PM) (OpenAirDocs)
- Registry engine: [Mcculloch ALL MDLS A/B](https://openairdocs.org/engine/mcculloch-all-mdls-a-b) (registry code 43102, reciprocating) (OpenAirDocs)
- Category: Gyroplane, amateur-built
- Serial number: 86
- Airframe hours: 65
- Engines: McCulloch O-100 90 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Donald E. Willi
- Registered owner: Donald E Willi
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Unknown, August 7, 1987, 29 hours before
- Airport: D13, Mckinley Fraser, runway 27, 2,910 × 50 ft, macadam

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 33; student; medical: class 3, valid medical--no waivers/lim.; toxicology performed; flight hours: 75 total, 75 in this make and model, 25 in the last 90 days, 17 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 250° at 3 knots
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: 63 °F, dew point 39 °F
- Altimeter: 30.00 inHg
- Observed at: MTC, 8 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 19870925082169A](https://openairdocs.org/incident/19870925082169A), Sep 25, 1987: Amtrbx BENSENB8M, Frasher, MI, Substantial damage. Lost power and crashed on takeoff. Seat tank sealer clogged the fuel filters and jammed check valve. Scraped tank.

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.

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