Summary
This document proposes to adopt a new airworthiness directive (AD) that would apply to 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. The proposed AD would require 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. The proposed 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 the proposed 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.