For approach aircraft category classification, what is the required formula?

The required formula for approach aircraft category classification is based on a multiplier of the stall speed in a specified configuration, either the stall speed in the landing configuration (V_SO) or the reference landing approach speed (V_REF). The correct choice of 1.3 times V_SO or V_REF aligns with the established criteria set by the FAA in determining the approach category of an aircraft. This multiplier is used to ensure adequate safety margins for handling and performance during the critical phases of flight, particularly approach and landing.

Using this formula is vital for categorizing aircraft into appropriate groups such as A, B, C, or D, based on their approach speeds, which ultimately guides operational procedures and spacing requirements at airports. The calculation helps in maintaining safe separations between different types of aircraft during approach and landing phases. Other multipliers, such as 1.5 or 1.1, are not applicable for this specific classification and do not conform to the FAA guidelines for approach category determination, while a multiplier of 1.0 does not provide a sufficient safety buffer. Therefore, it's essential to use the 1.3 factor to accurately define approach categories and enhance flight safety.