What do the red numbers on an airway indicate?

The red numbers on an airway indicate speed restrictions. In aviation, red markings are generally used to highlight important information that pilots must adhere to, including maximum or minimum speed limits along specific segments of an airway. These restrictions are crucial for maintaining safe separation between aircraft and ensuring efficient traffic flow in controlled airspace.

Understanding speed restrictions is essential for flight planning and flight safety, as they help pilots manage their aircraft's speed to comply with air traffic control directives and avoid potential conflicts with other aircraft.