After being off the air for more than how many hours should ATIS resume with identification code Alpha?

• A. 12
• B. 8
• C. 10
• D. 24

Answer: (A)

The concept here is how ATIS labeling works to keep pilots from using stale information. ATIS information is tagged with a sequential identifier (Alpha, Bravo, Charlie, etc.) to show which broadcast is current. When ATIS has been off the air for a long enough period that the previous data could be outdated, the restart uses Information Alpha to signal a fresh information cycle and avoid confusion with any older message still in memory on pilots’ equipment.

The rule uses a 12-hour threshold: after being off the air for more than 12 hours, the signal restarts with Alpha. This helps ensure that pilots know the information they’re about to receive is new, not a continuation of something that might have changed long ago. Resuming with a later identifier could mislead about the timeliness of the data, and shorter intervals wouldn’t guarantee that everything has become stale. A longer interval, like 24 hours, isn’t the standard reset point in this procedure.

So, after more than 12 hours of silence, ATIS resumes with the Alpha designation to clearly indicate a fresh information cycle.