Transport Canada CF 2023-35

Requires left-hand direct current power center (DCPC) internal communication data bus units to be removed and cleaned by the avionics OEM and modified by adding a protective layer of tape to prevent the ingress of contaminants into the printed circuit board cage. Prompted by occurences of misleading electrical system status indications as a result of contamination of electrical contacts in the left-hand DCPC unit that could cause the crew to turn off fully operational electrical power sources, leading to partial or complete loss of electrical power.