What is the maximum allowed configuration of flaps during landing?

The maximum allowed configuration of flaps during landing for the ERJ 170/175 is indeed Flaps 28. This configuration helps to optimize the wing's lift characteristics and drag reduction, which is critical during the landing phase when lower speeds are involved.

Utilizing Flaps 28 allows for a greater lift coefficient, which enables the aircraft to maintain a stable approach while reducing stall speed. This configuration also contributes to a steeper descent profile and shortens landing distances, making it particularly advantageous for landing on shorter runways or in less-than-ideal conditions.

Other flap settings, such as Flaps 5, Flaps 10, and Flaps 15, are not adequate for landing as they provide insufficient lift. These configurations are typically used for takeoff or initial phases of flight rather than the optimal conditions required when approaching the runway for landing.