Summary
We propose to adopt a new airworthiness directive (AD) for certain Rockwell Collins, Inc. TSS-4100 Traffic Surveillance System Processing Units that incorporate TSSA-4100 Field Loadable Software (FLS) Rockwell Collins part numbers 810-0052-002/ -003/-010/-011/-012/- 100/-101 and are installed on airplanes. This proposed AD was prompted by five instances of air traffic control observing coasting (extrapolated stale data) of automatic dependent surveillance-broadcast data (position/ velocity data). This proposed AD would require installing the TSSA-4100 FLS upgrades on the TSS-4100 units. We are proposing this AD to correct the unsafe condition on these products.