On December 11, two aircraft, DAL1070 and UAL1724, were on approach to KPHX and were at about 4000 feet when the TCAS system in both aircraft warned the two flight crews of an imminent situation and issued an RA. The Delta crew was responding to a heading instruction from ATC when their TCAS could clearly be heard in the background advising the crew to "Descend, Descend". Both flight crew announced to ATC that they were responding to an RA. Both flights were re-sequenced for landing and landed safely a short time later. Oh boy....Whew!
