Airworthiness Directives; SAFT America Inc. Part Number (P/N) 021929-000 (McDonnell Douglas P/N 43BO34LB02) and P/N 021904-000 (McDonnell Douglas P/N 43BO34LB03) Nickel Cadmium Batteries

This amendment adopts a new airworthiness directive (AD) that applies to certain SAFT America Inc. P/N 021929-000 (McDonnell Douglas P/N 43BO34LB02) and P/N 021904-000 (McDonnell Douglas P/N 43BO34LB03) nickel cadmium batteries that are installed on aircraft. This AD requires replacing all battery terminal screws, verifying that the battery contains design specification cells, and replacing the cells if the battery contains non-design specification cells. This AD is the result of an incident where the cell screws on one of the affected batteries were exposed to chloride, which caused the heads of some fasteners to shear off and eventually resulted in the battery exploding. The actions specified by this AD are intended to prevent such an occurrence, which could result in loss of emergency power to electrical flight components or other emergency power systems required in the event of loss of the aircraft primary power source.