The IVA-81D Traffic Advisory/Resolution Advisory/Vertical Speed Indicator combines the vertical speed instrument with the TA and RA display functions. Red and green bands around the circumference of the screen give RA information. Traffic location is presented on the face of the display inside the vertical speed scale. The TA Select Pushbutton can be wired for either a Traffic Select or Switchable configuration at time of installation. In both configurations, when a TA or RA is present all traffic pop-up on the display. Pressing the button alternates between showing all traffic and VSI display only. When the display is clear of traffic, presence of a new TA or RA intruder pop-up all traffic on the display. Without traffic the instrument operates as a VSI only.

The IVA-81D is part of the TCAS II system. The TCAS II is a system used for detecting and tracking aircraft in the vicinity of your own aircraft. By interrogating their transponders it analyzes the replies to determine range, bearing, and if reporting altitude, the relative altitude of the intruder. Should the TCAS II processor determine that a possible collision hazard exists, it issues visual and audio advisories to the crew for appropriate vertical avoidance maneuvers. There are two types of cockpit displays for TCAS II, the Resolution Advisory (RA) display and the Traffic Advisory (TA) display. The RA display is incorporated into the vertical speed indicator (VSI). By illuminating red and green arcs around the dial it displays the required rate, or limitation of climb or descent, to avoid a possible collision. For all NVIS types, when the NVIS mode is selected, the pointer, border, numerals and the scale graduations which are normally white will be green.