Mechanical & Engine Failure · NTSB ERA10LA102

DAVIS MICHAEL J LONGEZ — Dexter, KY

1 fatal
DateDecember 25, 2009
LocationDexter, KY
AircraftDAVIS MICHAEL J LONGEZ (amateur-built)
Purpose of flightPersonal
ConditionsDay · Visual Meteorological Cond
Phase / occurrenceEmergency descent Off-field or emergency landing
Pilot age52
Pilot total time925 hrs · Building experience
Time in typeUnknown
Fatalities1

Probable cause

The loss of engine power due to the chaffing and grounding of the single magneto's ignition lead.

NTSB findings

  • Aircraft-Aircraft power plant-Ignition system-Magneto/distributor-Incorrect service/maintenance - C
  • Aircraft-Aircraft power plant-Ignition system-Ignition power supply-Design - F

What happened

A witness observed the experimental, amateur built airplane perform a steep bank in an aerobatic-type maneuver. After about 30 seconds, he observed a large explosion as the airplane’s left wing separated during its collision with trees. The airplane continued its descent and impacted the ground inverted between a residential driveway and the row of trees. The airplane was consumed by the subsequent fire.

A postaccident examination revealed that the engine’s single magneto P-lead terminal end had made contact with an adjacent fabric covered steel braid oil cooler hose line. Closer examination of the ignition lead disclosed that chaffing had exposed the metal strand layer of the hose. The grounding of the magneto would have rendered the engine unable to produce power due to the lack of an ignition source. The condition of the propeller blades at the wreckage was consistent with the engine not operating at the time of ground impact.

An editorial "what led to it / how to avoid it" analysis for this accident is generated separately and will appear here.

View the official NTSB docket →