During which event is the emergency oxygen cylinder automatically activated?

The emergency oxygen cylinder is automatically activated during the ejection sequence. This is a critical safety feature designed to ensure that the pilot has access to oxygen during the rapid decompression and potential altitude changes that occur when ejecting from the aircraft. The ejection process may cause the cockpit to lose pressure suddenly, exposing the pilot to hypoxia if supplemental oxygen is not provided.

In this scenario, the activation of the emergency oxygen supplies the pilot with essential breathing air necessary for survival, particularly at high altitudes where the atmosphere has insufficient oxygen. Other options, while they involve scenarios that may compromise the operational integrity or safety of the aircraft, do not specifically trigger the automatic deployment of the emergency oxygen system in the same manner as the ejection sequence does.