Description / Abstract: This document considers functional requirements consisting of: airborne surveillance and separation assurance processing (ASSAP), and cockpit display of traffic information (CDTI) as described in the Aircraft Surveillance Applications (ASA) Minimum Aviation System Performance Standards (MASPS), RTCA Document DO 289, and in the Safety, Performance and Interoperability Requirements documents for the applications approved by RTCA SC-186 and EUROCAE WG-51: ATSA-AIRB (DO-319/EUROCAE DOCUMENT ED-164), ATSA-VSA (DO-314/ED-160), ATSA-ITP (DO-312/ED-159) ATSA-SURF (DO-322/ED-165), TSAA (DO-348/ED-232), and CAVS (DO-354/ED-233). Operational performance standards for functions or components that exceed the stated minimum requirements are identified as optional features.

DO-317B incorporates the following "prime" differences from DO-317A:

Traffic Situation Awareness with Alerts (TSAA): Traffic Situation Awareness with Alerts (TSAA) is an application that is intended to reduce the number of mid-air collisions and near mid-air collisions involving general aviation aircraft. TSAA provides voice annunciations to flight crews to draw attention to Target Aircraft and also adds visual cues to the underlying basic traffic situation awareness. The TSAA application uses ADS-B information, and where available Automatic Dependent Surveillance-Rebroadcast (ADS-R) and Traffic Information Service-Broadcast (TIS-B) information to provide the flight crew with indications of nearby aircraft in support of their see-and-avoid responsibility.

CDTI Assisted Visual Separation (CAVS): Similar to VSA, the CDTI is used to assist the flight crew in acquiring and maintaining visual contact with a preceding aircraft (designated traffic) while performing a visual separation on approach procedure in Visual Meteorological Conditions (VMC). The fundamental difference between VSA and CAVS is that the flight crew is authorized to use the information provided by the CDTI for the preceding aircraft, after visual acquisition and cross correlation on the CDTI, as a substitute for out the window information while performing the CAVS procedure. Therefore, once the preceding aircraft has been acquired by correlating the traffic on the CDTI with a visual acquisition of the traffic out-the-window, the CAVS procedure can continue through the use of the Traffic Display when the traffic information out-the-window is no longer available (for example, lost in lights during approach at night). CAVS can be used for parallel runway operations; however it cannot be used for designated traffic closer than the Caution "CAVS Minimum Range" Alert threshold