WRIGHT B FLYER INC WRIGHT B FLYER — Springfield, OH, 2011

WRIGHT B FLYER INC WRIGHT B FLYER — Springfield, OH

2 fatal High-time pilot

Date	July 30, 2011
Location	Springfield, OH
Aircraft	WRIGHT B FLYER INC WRIGHT B FLYER (amateur-built)
Purpose of flight	Flight Test
Conditions	Day · Visual Meteorological Cond
Phase / occurrence	Enroute-cruise Loss of engine power (partial)
Pilot age	64
Pilot total time	3,078 hrs · High time
Time in type	235 hrs
Fatalities	2

Probable cause

The flight crew’s failure to maintain airplane control following a partial loss of engine thrust during cruise flight. Contributing to the accident was the failed weld as a result of incomplete welding on the left propeller shaft, which led to the partial loss of engine thrust.

NTSB findings

Aircraft-Aircraft propeller/rotor-Propeller system-Propeller assembly-Failure - F
Personnel issues-Task performance-Use of equip/info-Aircraft control-Flight crew - C
Aircraft-Aircraft oper/perf/capability-Performance/control parameters-(general)-Not attained/maintained - C
Personnel issues-Task performance-Maintenance-Fabrication-Owner/builder - F

What happened

The experimental amateur-built replica airplane was on a test flight with two pilot-rated occupants. Another pilot heard a radio transmission from the accident airplane indicating that they were going to land in a field about 5 miles north of the departure airport. Witnesses reported that the airplane’s engine rpm varied while it was flying at a low altitude. The airplane was then observed in a spiraling descent to the ground. Postaccident examination of the airplane’s left propeller shaft revealed a broken weld, which would have prevented the left propeller from being driven by the engine. Further examination of the joint identified incomplete weld penetration during welding, thus about 25 to 35 percent of the through thickness of the propeller shaft tube was not welded to the propeller shaft end. This incomplete weld penetration occurred in the inner areas of the joint. Visible defects, such as pores and voids, were observed in the welded areas. The part’s engineering drawing specifies complete weld penetration. The on-scene accident examination of the wreckage did not reveal any other preimpact anomalies. Despite the resultant partial loss of thrust, the flight crew should have been able to maintain control of the airplane during the forced landing attempt.

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