What is the standard altimeter setting for the Northern Domestic Airspace?

The standard altimeter setting for the Northern Domestic Airspace is 29.92 inches of Mercury (Hg). This standardization is crucial because it serves as a baseline pressure reference for pilots to ensure accurate altitude readings and maintain safe vertical separation between aircraft.

Using 29.92"Hg aligns with the International Civil Aviation Organization (ICAO) standards, which provide a standardized atmospheric pressure for the purposes of altimeter calibration. Pilots adjust their altimeters to this value when flying above the transition altitude, ensuring uniformity in altitude reporting and air traffic control operations. This practice minimizes the risks associated with altitude discrepancies that could arise if altimeters were set to varying pressure values.

In contrast, the other options represent different altimeter settings that are not considered standard for the Northern Domestic Airspace, and could lead to confusion or potential risks in altitude accuracy if used incorrectly.