A.D. Notes are issued bring attention to parts or conditions of parts that are unsafe for flight. The Service Bulletins and Service Letters that follow the A.D. Notes will detail procedures to inspect and/or correct these unsafe conditions.

The following picture is presented as an example of component failure caused by an unsafe condition.

We welcome submissions of photo's and other information that can be presented here to inform the aviation community about propeller and propeller component failure. Please contact Prop Center by e-mail for information.

The following propeller was installed on a Piper PA34-200 Seneca I. An illegal repair had been performed on the pitch change knob of this blade. An unknow party machined off the old knob, then drilled and tapped threads in this blade butt, and installed their own replacement knob. You can see the threads on the blade butt. The blade knob is a part of the blade forging from the manufacturer.

Broken blade pitch change knob.

Blade butt showing threaded area of replacement knob.