What system transmits routine operational, maintenance, and administrative messages to airliners via a digital data link?

The correct answer, ACARS, stands for Aircraft Communications Addressing and Reporting System. This system is specifically designed to facilitate the transmission of messages related to operational, maintenance, and administrative tasks in a digital format between aircraft and ground stations. ACARS operates over VHF radio, satellite, or other digital communication networks, enabling airlines to send and receive messages efficiently.

Through ACARS, messages such as weather updates, flight instructions, and maintenance requests can be communicated without the need for voice communication, allowing for more accurate data exchange and freeing up air traffic controllers for other critical tasks. It greatly enhances the operational efficiency of airlines by ensuring that vital information is transmitted promptly and accurately.

Other options, while related to aviation, serve different purposes. VOR (VHF Omni-directional Range) is a type of radio navigation system for aircraft, providing accurate azimuth information to pilots rather than data messaging. NDB (Non-Directional Beacon) is another navigation aid used primarily for en-route navigation rather than for operational communication. SELCAL (Selective Calling) allows ground stations to send signals to alert pilots of incoming messages, but it does not handle the transmission of the operational and maintenance messages themselves, making it a complementary system rather than a standalone data link for routine messages