3TIS Operation and SymbologyPart One: Section 1and avoid.” Some of the more common examples ofthese errors follow:• When client or intruder aircraft maneuvers exces-sively or abruptly, the tracking algorithm mayreport incorrect horizontal position until themaneuvering aircraft stabilizes.• When a rapidly closing intruder is on a course thatcrosses the client aircraft course at a shallow angle(either overtaking or head on) and either aircraftabruptly changes course within ¼ NM, TIS maydisplay the intruder on the opposite side of theclient than it actually is.These are relatively rare occurrences and willbe corrected in a few radar scans once the coursehas stabilized.Improving TISUsers of TIS can render valuable assistance inthe correction of malfunctions by reporting theirobservations of undesirable performance. Reportersshould identify the time of observation, location, typeand identity of aircraft, and describe the conditionobserved; the type of transponder processor and soft-ware in use can also be useful information. Since TISperformance is monitored by maintenance personnelother than ATC, it is suggested that malfunctions bereported in the following ways:• By telephone to the nearest Flight Service Station(FSS) facility.• By FAA Form 8000-7, Safety Improvement Report,a postage-paid card designed for this purpose.These cards may be obtained at FAA FSSs, GeneralAviation District Offices, Flight Standards DistrictOffices, and General Aviation Fixed Based Opera-tions.TIS SymbologyTIS traffic is displayed on the 400W/500W Seriesunit according to TCAS symbology, graphicallydisplayed on a dedicated graphical page (Traffic Page;see below), and on the moving Map Page. A TrafficAdvisory (TA) symbol appears as a solid yellow circle(or half circle on the outer range ring if the trafficis outside the range of the dedicated Traffic Page).All other traffic is displayed as a hollow white dia-mond. Altitude deviation from own aircraft altitudeis displayed above the target symbol if traffic is aboveown aircraft altitude, and below the symbol if they arebelow own aircraft altitude. Altitude trend is displayedas an up arrow (> +500 ft/min), down arrow (< -500ft/min), or no symbol if less than 500 ft/min rate ineither direction.• Traffic Advisories (TA)—Yellow• Proximity Advisories (PA)—White• Other—White190-00356-30 Rev C