SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all Piper Aircraft, Inc., (Piper) Models PA-46-350P (Malibu Mirage), PA-46R-350T (Malibu Matrix), and PA-46-500TP (Malibu Meridian) airplanes. This AD was prompted by a finding of several airplanes with wing assemblies that did not have the proper stall warning heater modification design. Without the proper stall warning heat control modification kit installed, during flights into icing conditions with the landing gear down, ice can form on the stall vane, which may result in failure of the stall warning system. This AD requires identifying and correcting nonconforming stall warning heat control systems. The FAA is issuing this AD to address the unsafe condition on these products.