What is required to select an enroute alternate aerodrome for an ETOPS flight?

Selecting an enroute alternate aerodrome for an Extended-range Twin-engine Operational Performance Standards (ETOPS) flight is governed by specific criteria to ensure safety during unforeseen circumstances, such as aircraft diversion. The requirement that the ceiling must be at least the Decision Height (DH) plus 500 feet, along with visibility being above 1500 meters, provides a safety margin that ensures pilots have a better chance of safely executing an approach and landing, should they need to divert.

This criterion is essential because it takes into account the minimum visibility and cloud cover needed for a successful landing, aligning with operational and safety standards set forth for ETOPS flights. These standards are particularly stringent because once an aircraft is beyond a certain distance from a suitable alternate, the risks increase, necessitating higher minimums than typical operations might require.

Other options, while they cover important aspects of flight operations and safety, do not specifically define what is required for selecting an enroute alternate aerodrome. Rules concerning final reserve fuels and runway lighting are critical elements of flight readiness and safety but do not directly correlate with the selection criteria for an alternate during ETOPS operations.