Aircraft X received a false TCASII alert and made an unauthorized change to the company frequency, resulting in pilot deviation.
Synopsis
Aircraft X received a false TCASII alert and made an unauthorized change to the company frequency, resulting in pilot deviation.
Narrative
Rewritten in plain English from NASA’s original all-caps telegraphic report — facts, figures, and terminology preserved.
Aircraft X left frequency at a very critical period of the arrival rush (without advising ATC). He continued westbound descending to 4000 feet, southwest of OXI (toward the departure sector).
After three transmissions, he finally acknowledged, but by this time he had already jeopardized the safety of his aircraft and that of other aircraft inbound to ORD from the south. The pilot called ZAU supervisor where he admitted leaving frequency to call company operations to discuss TCASII alert over OXI (see TCASII graphic).
The pilot was extremely unprofessional in his attempt to monopolize frequency time prior to, and after, leaving the frequency to call company.
Show the original NASA report (verbatim, telegraphic)
ACR X LEFT FREQ AT A VERY CRITICAL PERIOD OF THE ARR RUSH (WITHOUT ADVISING ATC). HE CONTINUED WBOUND DSNDING TO 4000 FT; SW OF OXI (TOWARD THE DEP SECTOR). AFTER 3 XMISSIONS HE FINALLY ACKNOWLEDGED BUT BY THIS TIME HE HAD ALREADY JEOPARDIZED THE SAFETY OF HIS ACFT AND THAT OF OTHER ACFT INBOUND TO ORD FROM THE S. PLT CALLED ZAU SUPVR WHERE HE ADMITTED LEAVING FREQ TO CALL COMPANY OPS TO DISCUSS TCASII ALERT OVER OXI (SEE TCASII GRAPHIC). PLT WAS EXTREMELY UNPROFESSIONAL IN HIS ATTEMPT TO MONOPOLIZE FREQ TIME PRIOR TO; AND AFTER; LEAVING THE FREQ TO CALL COMPANY.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.