Which altitude reading is not acceptable at a barometric pressure of 25.842?

To determine the acceptability of altitude readings at a specific barometric pressure, it is important to understand the relationship between pressure altitude, true altitude, and the standard atmospheric pressure. At a barometric pressure of 25.842 inHg, it is essential to convert the pressure to a corresponding altitude using the standard atmosphere model.

Under standard conditions, each inch of mercury corresponds to a specific altitude above sea level, with higher altitudes associated with lower barometric pressures. The typical sea level pressure is 29.92 inHg. Therefore, a barometric pressure of 25.842 indicates that the altitude must be adjusted because it is significantly lower than standard pressure.

When calculating the altitudes based on this pressure setting, we find that some of the provided altitudes align closely with what would be expected at that pressure, while one of the options, in this case, shows a discrepancy. Specifically, the reading of 4,046 feet would exceed typical expectations for a barometric setting of 25.842 inHg, making it the altitude reading that stands out as unacceptable.

Therefore, when analyzing the readings against the expected outcomes based on the barometric pressure configuration, option B emerges as the one that deviates from what would be considered an