United's Flagship 787 Grounds Again Over TCAS Glitch

United’s first premium-heavy 787-9 (N61101), the launch aircraft for its Elevated cabin, has been grounded again after reports of a TCAS (Traffic Alert and Collision Avoidance System) issue. Boeing replaced TCAS antennas during a Moses Lake maintenance visit, but the aircraft returned to service only to be pulled from flight again, with a London-to-San Francisco leg canceled. United says safety is the priority while Boeing and the airline investigate whether the fault is a Boeing installation, software, or related component issue, and work to fully resolve it before returning the aircraft to long-haul service.