Photograph showing the fractured rudder post on N4206H.

​​​Photograph showing the fractured rudder post on N4206H (case number ANC21LA064).

Structural Failure of Piper Part Number 40622 Rudder Posts Made of 1025 Carbon Steel

Investigation Details

What Happened

​​​The National Transportation Safety Board (NTSB) is providing the following information to urge the Federal Aviation Administration (FAA) to take action on the safety recommendation in this report. This recommendation is derived from the NTSB’s investigations of two accidents involving airplanes, designed and built by Piper Aircraft Inc. (Piper), that sustained substantial damage when their rudders structurally failed in flight.

For both accident investigations, the NTSB’s findings indicate that the rudder post fractured above the upper hinge and the top portion of the rudder folded over the upper tail brace wires, resulting in diminished control of the airplane. The NTSB has determined that the rudders were consistent with Piper part number 40622 and that the rudder posts were made of American Iron and Steel Institute (AISI) 1025 carbon steel and likely fractured due to fatigue. Additional support for this recommendation is derived from the examination of similarly fractured rudder posts.

What We Found

​​It is likely that each of the five recently examined Piper Aircraft Inc. part number 40622 rudder posts, all made of American Iron and Steel Institute 1025 carbon steel, fractured due to fatigue.

Posts made of American Iron and Steel Institute 1025 carbon steel in Piper Aircraft Inc. part number 40622 rudders are susceptible to fatigue cracking under normal service conditions.

Recently documented structural failures of Piper Aircraft Inc. part number 40622 rudders equipped with a post made of American Iron and Steel Institute 1025 carbon steel indicate a serious hazard to flight safety that warrants action.

What We Recommended

​The NTSB is issuing one recommendation to the FAA.


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