Brasilia EMB-120 All Series
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Distraction; Situational Awareness; Workload
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Altitude Excursion From Assigned Altitude
Flight Crew Took Evasive Action
Airspace Structure; Human Factors; Procedure; Airport
While being vectored for landing and Palm Springs 13 right; ATC asked us to descend 2;000 feet from our present altitude. At the time; we were closely in trail of another aircraft 2;000 feet below us. In addition; we had an aircraft at our 4 o'clock position overtaking us and below us. We advised ATC we were unable to comply with their instruction because of conflicting traffic. The area was extremely heavy with traffic and the ATC controller seemed to be overwhelmed. We told the controller multiple times we were unable to comply with his instructions due to conflicting traffic but never received a response. We then received an RA and complied with the RA. We informed ATC that we were leaving our altitude responding to an RA. ATC responded; then gave us new instructions and we complied and landed without further incident.I believe the root cause was heavily congested airspace and an extremely busy air traffic controller. There was an event in Palm Springs that weekend which probably increased traffic significantly.Possibly add an additional controller with an additional frequency when traffic gets that busy; or maybe have arrival slots when an event is going on. Another possibility would be to use flow control into the area to avoid such congestion.
While descending could have prevented one RA we were already getting traffic alerts and had at least 3 conflicts below making descending into them reckless. We voiced a very specific concern and it was not addressed. As our fear was ATC overlooking something (the traffic below us) his lack of acknowledgement of our concern only heightened our suspicion.
Unable to complete a necessary communication with Approach control regarding a descent clearance into busy PSP traffic below them; an EMB-120 flight crew delayed their descent; but then received a TCAS 'descend' RA to which they complied.