Fuel Exhaustion & Starvation · NTSB WPR14FA165

WILLIAMS MYRON G BOWERS FLY BABY 1A — Mariposa, CA

1 fatal High-time pilot
DateApril 11, 2014
LocationMariposa, CA
AircraftWILLIAMS MYRON G BOWERS FLY BABY 1A (amateur-built)
Purpose of flightPersonal
ConditionsDay · Visual Meteorological Cond
Phase / occurrenceEnroute-cruise Aerodynamic stall/spin
Pilot age80
Pilot total time1,800 hrs · Experienced
Time in type3 hrs
Fatalities1

Probable cause

The partial loss of engine power due to an improperly maintained carburetor and the pilot's subsequent failure to maintain aircraft control.

NTSB findings

  • Aircraft-Aircraft power plant-Engine fuel and control-Fuel control/carburetor-Incorrect service/maintenance - C
  • Personnel issues-Task performance-Use of equip/info-Aircraft control-Pilot - C
  • Personnel issues-Experience/knowledge-Training-Recurrent instruct/training-Pilot

What happened

The plans-built single-seat airplane had been constructed about 8 years before the accident by another individual, who had flown it about 30 hours before it was purchased by the current owner/pilot. In the year since the purchase, due to the low build-quality of the airplane, the pilot had made several modifications and repairs to the airplane. The accident flight was the pilot's fifth flight in the airplane. Review of the pilot's flight logbook indicated that his most recent flight review occurred about 7 years before the accident and that he had flown only 15 hours in the 2 years before the accident.

A witness reported that shortly after takeoff, when the airplane was about 3 miles from the airport, the engine began making a sound as if power was intermittently being interrupted. The nose of the airplane began to pitch up aggressively as it flew out of view. The wreckage location, wreckage distribution, and impact signatures indicated that the airplane struck the ground in a steep nose-low attitude, consistent with an aerodynamic stall event.

Postaccident examination of the carburetor revealed multiple maintenance-related discrepancies, any one of which could have resulted in the loss of engine power. Additionally, before the accident, the pilot reported to a friend that the airspeed indicator was not reliable and that the airplane exhibited roll control anomalies. Both of these conditions would have hindered the pilot's ability to safely operate the airplane.

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 →