A cache system and a method for controlling the cache system are provided. Each of the vertical posts is provided on two lateral sides with one longitudinal row of holes each. In addition, at least one source port, one destination port, and one protocol are grouped in a protocol group. As such, each of the propellers can be adjusted to exhibit a first blade pitch angle distribution optimized for vertical flight and a second blade pitch angle distribution optimized for forward flight. The display control device is configured to control a display section to indicate the hypothetical contaminant existence rate. One example method comprises, during selected engine fueling conditions, alternating between applying different voltages to the sensor; and identifying an amount of alcohol in fuel injected to the engine based on sensor outputs at the different voltages.