PA–12 accident prompts rudder failure inquiry

In an airworthiness concern sheet, the FAA is requesting information about rudder failures from operators of Piper single-engine airplane models J–5A, J–5B, J–5C, J–5D, AE–1, HE–1, PA–12, PA–12S, PA–14, PA–16, PA–18, L–21, PA–20, and PA–22 of all serial numbers.

In the accident in question, the rudder post “broke just above the top hinge and the upper part of the rudder folded over the tail brace wires in such a way that rudder control was severely limited and as to effectively create an additional horizontal tail, driving the tail down and the nose up. It was possible for the senior flight instructor to control the airplane in pitch, but required a lot of the available elevator deflection to do so. By dropping the water rudders, some directional control was established and the airplane was able to return to base and land, but with difficulty,” the ACS says.

The FAA has not determined whether the failed rudder, which was being examined in an NTSB laboratory, was original equipment or a replacement part. It cited several similar accidents and noted that the current type certificate holder of the PA–12 was aware of two other rudder structure failures.

Operators of the noted Piper models are requested to reply as provided in the ACS regarding any rudder failures observed, information about possible causes, suggested solutions, and any observed rudder vibrations and “any correlation with the presence or absence of a strobe or beacon on the top of the rudder.”

The FAA also noted that interviews conducted with some repair stations specializing in Cubs indicate that “a significant number of additional events may have occurred in the fleet of the long history of PA–18 and PA–12 airplanes.”