Mechanical & Engine Failure · NTSB CEN13LA433

CLAYTON GERALD H GLASTAR GS-1 — Columbus, IN

1 fatal Low-time pilot
DateJuly 25, 2013
LocationColumbus, IN
AircraftCLAYTON GERALD H GLASTAR GS-1 (amateur-built)
Purpose of flightPersonal
ConditionsDay · Visual Meteorological Cond
Phase / occurrencePrior to flight Aircraft maintenance event
Pilot age81
Pilot total time286 hrs · Low time
Time in type66 hrs
Fatalities1, 1 serious

Probable cause

Slippage in the engine clutch and gear reduction module and a resultant uncommanded movement of the propeller blades into reverse thrust.

NTSB findings

  • Aircraft-Aircraft power plant-Engine (reciprocating)-(general)-Not specified - C
  • Aircraft-Aircraft propeller/rotor-Propeller system-Propeller controlling system-Malfunction - C
  • Environmental issues-Physical environment-Object/animal/substance-Residence/building-Contributed to outcome

What happened

Family members and friends reported that, 2 years before the accident, the experimental, amateur-built airplane had experienced a serious in-flight engine problem. Since that time, the pilot had been repairing the engine and propeller system, and the accident flight was the airplane's first flight following the reported engine problem.

The pilot-rated passenger reported that, just after departing for a short local flight and turning the airplane to enter the downwind leg of the airport traffic pattern, the pilot informed him that there was a problem and that they needed to return to the airport. He added that the pilot began working "frantically on an electric switch for the propeller" while the engine was "screaming" but that the airplane continued descending. The airplane struck a tree and then impacted a house. An explosion and a postimpact fire immediately ensued, which consumed most of the airplane and the house. The pilot and passenger were able to exit the burning wreckage without assistance.

An examination of the engine clutch and gear reduction module found some metal contamination and a nonstandard displacement of the sprag clutch elements, and these issues likely resulted in clutch slippage, which can lead to the uncommanded movement of the propeller blades. The propeller blades were observed to be in about 5 degrees of reverse pitch, which would result in a substantial loss of glide capability.

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 →