Final answer:
Yes, one can legally fly along a 'T' route such as T265 west-southwest of Chicago if the aircraft is equipped with GPS, as 'T' routes are designed for RNAV equipped aircraft and are available for civil aviation use.
Step-by-step explanation:
The question asks whether you can legally fly along a 'T' route west-southwest of Chicago. The correct answer is: 3) Yes, if your aircraft is GPS equipped because 'T' routes are RNAV routes. T-routes are low-altitude airspace routes based on RNAV, which stands for Area Navigation.
RNAV routes allow for more direct and efficient navigation between two points, and 'T' routes are specifically designed for aircraft equipped with GPS capabilities. They are not exclusive to the military or national defense; rather, they are open for use by any civil aircraft with the proper equipment.