Under what condition do ADSE crews lose their certification?

The correct answer is based on the requirement for sustaining operational effectiveness within an ADSE team. ADSE crews lose their certification when they do not maintain at least two certified crews as a collective operational capability. This condition ensures that there is sufficient redundancy and skill within the team to effectively perform air defense operations.

Having at least two certified crews allows for continuity in operations and ensures that training and readiness levels are maintained. In case one crew is unavailable due to various reasons, the other crew can still carry out critical missions. This is seen as a best practice in military operations to ensure that air defense capabilities remain robust and reliable.

While the other options involve elements of performance or operational readiness, they do not specifically capture the essential requirement of crew certification accountability tied to personnel numbers and team structure, which is vital for mission sustainability. Thus, not having at least two certified crews directly impacts the team's certification status.