No, because TCAS II is installed under an aircraft STC approval, whatever part number is indicated in the TCAS II STC for that aircraft must be installed.  This is not referring to the IVA-81A to IVA-81D replacement that is addressed in another FAQ.

Yes, the IVA-81D is a fit, form, and function replacement for the IVA-81A TCAS Indicator. The IVA-81D replacement should be strongly considered when replacing a defective IVA-81A in an existing TCAS system or the installation of an IVA-81A indicator into a new TCAS installation. This is due to the fact that certain parts (such as the CRT) for the IVA-81A will no longer be available in the very near future.

Yes, with its improved design, the IVA-81D (P/N 066-01171-XXXX) is a direct fit, form, and function replacement for the IVA-81A (P/N 066-50001-XXXX). Click Here to see the Installation Bulletin from Honeywell.

If the aircraft in question is capable of single pilot operation then only one TCAS indicator is required. Otherwise, if the aircraft's operation requires a flight crew of 2 or more then 2 indicators are required.

TCAS II is a system used for detecting and tracking aircraft in the area of an aircraft. TCAS interrogates transponders in other aircraft and analyzes the replies to determine range, bearing, and relative altitude (if reporting) of the intruder aircraft. When the TCAS II processor determines that a potential collision hazard exists, it will issue visual and audio advisories to the pilot/copilot for appropriate vertical avoidance maneuvers. TCAS is not able to detect aircraft without an operating ATCRBS transponder (operating in Mode A and C) or a Mode S transponder.

TCAS II utilizes two types of cockpit displays, Resolution Advisory (RA) and Traffic Advisory (TA) display. The RA is incorporated into the vertical speed indicator (VSI). With illuminating red and green arcs around the dial, the VSI displays the required rate, or limitation of climb or descent, to avoid a collision. The TA display shows the intruding aircraft’s relative position and altitude with a trend arrow to indicate if it is climbing or descending greater than 500 feet per minute. The TA display may be presented on compatible weather radar indicator or MFD, dedicated TCAS display or a TA/VSI display. The TA display uses symbols and colors to identify the relative threat of each intruder. Supplementing the displays, TCAS II provides appropriate synthesized voice announcements.

Negotiating the exchange price of a unit only limits the allowable repair cap for the core unit. Southeast Aerospace's exchange transactions are based on the return of economically repairable core unit. Once the core is received and evaluated, the core repair cost incurred by SEA cannot exceed 80% of the original exchange price. That is, it cannot cost SEA more than 80% of the original OH/SV exchange price collected from the customer. Therefore, when and if an SEA exchange price is discounted, there is a risk that additional charges may be assessed once the core is returned and evaluated.

For more information, please refer to these other Exchange FAQs

The IVA-81A/D TCAS indicator combines the vertical speed instrument functions with the typical TCAS traffic display functions (position, altitude, trend).


The TID-66A/D is similar to the IVA-81A/C but does not include any vertical speed functions.

The IVA-81A/D have the same mating connector as the TID-66A/D. In the case that a TID-66A or TID-66D indicator needs to be replaced, the more functional, available IVA-81D is the optimal choice. This should be considered in any situation where the TID-66A/D is used in the CAS-66A system since the TID-66A/D is a unique indicator that is not readily available from the OEM or the aftermarket. Despite using the same mating connectors, some connections between the TID and IVA indicators are different since the IVA has vertical speed indication. Therefore, the configuration strapping between the 2 can be different and several pins locations would need to be addressed when upgrading to the IVA-81D.

The change from the TID to the IVA does not take into account any certification issues that may arise in changing the original system configuration.

Since there are versions of the IVA-81D TCAS indicator that operate on 28VDC or 115VAC, there are different installation kits for these varieties. The installation kit is simply the mating connector. The connector matches the unit variety it is to installed with. The various connectors are keyed differently to prevent DC units being installed into an AC aircraft and vice versa.

No, the IVA-81D only directly replaces the IVA-81A and IVA-81C. The IVA-81A/C/D are capable of displaying traffic advisories (TA), resolution advisories (RA), and vertical speed. The IVA-81B only displayed RAs and vertical speed.

The IVA-81D could be used in place of the IVA-81B. However, in most cases, a change would need to be made the original aircraft Type Certificate or Supplemental Type Certificate in addition to the installation being reconfigured to display TAs on the IVA-81D.