In the event of two-way communications failure while holding at a fix with an EFC time, what action should be taken?

When a two-way communications failure occurs while holding at a fix with an Expected Further Clearance (EFC) time, the correct action is to depart the holding fix at the EFC time. This procedure is in line with standard instrument flight rules and ensures that the aircraft adheres to the intended traffic flow and safety protocols established for managing airspace and approach procedures.

Choosing to depart the holding fix at the EFC time allows the pilot to maintain compliance with ATC expectations and minimizes the risk of prolonged holding, which could lead to fuel exhaustion or inefficient use of airspace. This action reflects a proactive approach to resolving communications issues while still acting in the best interest of operational safety and efficiency.

The other options imply different actions that, while potentially plausible, may not strictly align with the protocol established in situations of communication failure. For instance, simply holding until further instructions could lead to uncertainty about the aircraft's status and could impede traffic management efforts nearby. Departing at an unspecified point related to the EFC time might misalign with the intended procedures set forth by air traffic control, which emphasizes adherence to the EFC to ensure a smooth flow of air traffic. Hence, departing at the designated EFC time is the most appropriate and compliant course of action.