When may immediate compliance with an Airworthiness Directive be required?

Immediate compliance with an Airworthiness Directive (AD) is required when the AD is of an emergency nature. Such directives are issued when a safety concern arises that poses an immediate risk to the aircraft's airworthiness or operational safety. Emergency ADs typically require swift action to resolve critical issues, which could include equipment failures or structural deficiencies that, if left unaddressed, could lead to catastrophic failures during flight.

In contrast, regular maintenance checks and routine updates may not necessitate immediate compliance because they often deal with less urgent issues that do not pose an immediate threat to safety. Also, while an operator's request could lead to the assessment of certain safety concerns, it does not instigate an emergency requirement for compliance indicated by an AD. Only directives classified as urgent due to their potential safety implications necessitate prompt action.