These are the status light emitting diodes (LEDs):
· A green PASS to show that there is no TCAS computer
failure
· A red FAIL to show a TCAS computer failure
· A red XPNDR to show an ATC transponder interface failure
· A red UPPER ANT to show a top TCAS antenna failure
· A red LOWER ANT to show a bottom TCAS antenna failure
· A red RAD ALT to show no radio altitude data from the RA
· A red HDNG to show no heading data from the ADIRU
· A red R/A to show a DEU display function failure
· The red T/A does not operate.