TCAS/mode-S control panel.
TCAS II indicator.
Traffic symbols, traffic alert and collision avoidance system (TCAS-II).
A system that provides only a proximity warning to assist the pilot in the visual acquisition of intruder aircraft. The TCAS I neither provides nor authorizes any recommendations for avoidance maneuvers. The TCAS I is intended for use by smaller commuter aircraft holding ten to thirty passenger seats and general aviation aircraft. However, TCAS II does indicate traffic and resolution advisories. Resolution advisories provide recommended maneuvers in vertical plane (climb or descend) only to avoid conflicting traffic. The system is generally fitted on aircraft holding thirty-one or more passenger seats. If a pilot carries out any maneuver in response to TCAS II traffic advisories, he or she must inform ATC (air traffic control) as soon as is practicable.