What does the AIM state regarding altimeters below 28.00 or above 31.00?

In aviation, the AIM (Aeronautical Information Manual) provides guidelines for pilots regarding altimeter settings, particularly in relation to barometric pressure. When the altimeter setting falls below 28.00 inches of mercury or rises above 31.00 inches of mercury, it indicates extreme atmospheric conditions that can affect altitude readings critical for flight safety.

Under these circumstances, the AIM requires operational group approval, which means that pilots need to formalize their approach and adherence to altimeter settings with their respective operational authority. This ensures that pilots are prepared to face the challenges posed by such extremes in pressure, maintaining operational safety and effective communication regarding altimeter settings while conducting flights.

Choosing this option signifies an understanding of the importance of altitude precision and the standard practices required in unpredictable weather situations, ensuring that all pilots are operating under established safety protocols.