What happened
While the aircraft was in the climb phase of flight, one of the four propeller blades on the number two engine separated from the propeller hub. This separation caused immediate damage to another propeller blade and the fuselage. Shortly after the blade departed, the number two engine shut down.
The resulting rotational unbalance created extreme vibrations that caused significant damage to the wing and the engine/cowl assembly. Specifically, the upper portion of the engine cowl was deflected upward over the wing at an angle of approximately 30 degrees. This structural deformation led to airflow distortion, buffeting, and a degradation of roll control. To manage the descent and achieve a successful landing despite the excessive drag caused by the damage, the pilot was required to use maximum power on the number one engine.
The investigation
A metallurgical examination of the propeller components was conducted following the event. This examination revealed evidence of fatigue cracking within the propeller hub arm.