Which type of Airworthiness Directive is issued for immediate action due to an unsafe condition?

An Emergency Airworthiness Directive (AD) is specifically issued by the FAA when there is an urgent need to address an unsafe condition that poses an immediate threat to the safety of an aircraft. This type of AD is implemented rapidly, without the usual notice and comment period found in other regulatory processes, because the situation demands swift action to protect public safety.

Emergency ADs are typically issued when there is evidence that a hazard exists and corrective action is required as soon as possible to prevent accidents or incidents. This can arise from new findings related to aircraft safety, in-service experience, or reports of malfunction or failure of components that could lead to an unsafe condition.

In contrast, other types of ADs, such as Final Rules, Proposed Rulemaking, and Informational Bulletins, do not necessitate immediate compliance and are generally part of a longer regulatory process that allows for stakeholder input and does not emphasize pressing urgency. Thus, the distinctive characteristic of an Emergency AD is its requirement for immediate compliance due to an immediate risk, making it crucial for maintaining aviation safety.