Airworthiness Directives; Bombardier Inc. Model Otter DHC-3 Airplanes

This amendment adopts a new airworthiness directive (AD) that applies to certain Bombardier Inc. (formerly deHavilland Inc) Model DHC-3 (Otter) airplanes that have been modified in accordance with A.M. Luton Supplemental Type Certificate (STC) No. SA3777NM. This AD requires modifying the airplane's electrical system. The actions specified by this AD are intended to prevent electrical system failure caused by inadequate electrical system design, which could result in the loss of the engine instruments or a possible electrical fire in the airplane's cockpit.