# NTSB CHI89DEM10: Fletcher SONERAI-2L, N76DJ, Interlochen, MI, September 30, 1989

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Final report
- Date: September 30, 1989, 09:45 local (13:45 UTC)
- Place: Interlochen, MI
- Coordinates: 44.639736, -85.829391 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=44.6397&lon=-85.8294&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal
- Status: Completed, report September 5, 1991
- Report: Approved by Office Director
- NTSB case key (mKey): 14202
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI89DEM10
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/14202/pdf
- Page: https://openairdocs.org/ntsb/CHI89DEM10

## Probable cause

LOOSE CYLINDER DUE TO IMPROPER MAINTENANCE BY THE PILOT/OWNER, WHICH RESULTED IN OVERHEATING AND FAILURE OF THE ALUMINUM CYLINDER HEAD.  THE PRESENCE OF TREES WAS CONSIDERED TO BE A FACTOR.

## Sequence of events

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

- Loss of engine power(partial) - mech failure/malf, takeoff - initial climb
  - maintenance,installation - improper, company/operator management (cause)
  - engine assembly,cylinder - loose (cause)
  - engine assembly,cylinder - overtemperature (cause)
- Forced landing, maneuvering - turn to landing area (emergency)
- In flight collision with object, landing
  - object - tree(s) (contributing factor)

## Analysis

DURING THE INITIAL CLIMB AFTER TAKEOFF, THE ENG LOST POWER. SUBSEQUENTLY, THE PLT WAS UNABLE TO RETURN TO THE ARPT & THE ACFT COLLIDED WITH TREES DURING AN EMERGENCY LANDING. NEW VALVES HAD RECENTLY BEEN INSTALLED IN THE ENG. AN EXAM OF THE HOME BUILT ACFT'S ENG REVEALED THE #3 CYLINDER HEAD WAS LOOSE & A HOLE HAD MELTED IN THE ALUMINUM CYLINDER HEAD.

## Aircraft

- Registration: [N76DJ](https://openairdocs.org/deregistered/N76DJ-1990-08-10), registration cancelled 1990-08-10, S/N 9123 (OpenAirDocs)
- Reported make and model: FLETCHER SONERAI-2L
- Registry model: [Fletcher William D SONERAI II L](https://openairdocs.org/model/fletcher-william-d-sonerai-ii-l) (registry code 05659PE) (OpenAirDocs)
- Category: Airplane, amateur-built
- Serial number: 9123
- Engines: REVMASTER 2100D 85 horsepower reciprocating
- Damage: Destroyed
- Flight: Personal, Part 91
- Registered owner: Fletcher, William D.
- Airworthiness certificate: Special, Experimental (Special)
- Destination: 5D5, NORTHPORT, MI
- Airport: Y88, Green Lake, runway 23, 2,800 × 170 ft, grass/turf

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 61; commercial; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; seat: rear; toxicology performed; flight hours: 1,080 total, 77 in this make and model, 2 in the last 90 days, 2 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 170° at 8 knots
- Visibility: 30 statute miles
- Lowest ceiling: none
- Temperature: 61 °F, dew point 30 °F
- Altimeter: 30.00 inHg
- Observed at: TVC, 11 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 19890930037169A](https://openairdocs.org/incident/19890930037169A), Sep 30, 1989: Amtrmo SONERAI2, Interlochen, MI, Destroyed, 1 fatal. Engine problems on takeoff. Unable to climb, struck trees.

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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