Widebody Transport
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Flight Crew Last 90 Days 75; Flight Crew Total 8000; Flight Crew Type 2325
Situational Awareness
ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Took Evasive Action
Procedure; Human Factors
We were flying the JANNY3 into KBUR and due to gusty winds and a slight change of direction to our benefit; we elected to switch approaches from the ILS 8 to RNAV visual 33. SoCal cleared us direct to GZILA. We were cleared to 4000 ft and cleared for the approach. Around 4500 ft; ATC called and told us to climb to 5000 ft and that we set off an alert. We immediately climbed and leveled off at 5000 ft. With the change of approaches; we were very busy and failed to monitor and/or query the controller on our clearance. GZILA had a crossing restriction of 6000 ft and we should of had better situational awareness. Whether the mistake was due to ATC or us; we should have caught it with the terrain in the area.
We were inbound to Burbank on the JANNY 3 arrival when our approach was switched from the ILS RWY 8 to the RNAV visual Rwy 33; and were cleared direct to GZILA intersection; descend to 4000 ft. I turned the aircraft towards the GZILA intersection; put 4000 ft in the altitude window; and started a vertical descent on the MCP. Approaching GZILA intersection at approximately 4500 ft; we were informed by ATC that we have set off an altitude alert and instructed to climb immediately to 5;000 ft. We did so. My first officer and I were both extremely busy at this point of the arrival; especially with the change in approaches. Whether I misheard the clearance; or the controller misspoke; I should have noticed that GZILA intersection has a crossing restriction of 6;000 ft and questioned the clearance.
Air Carrier flight crew reported being cleared to a lower than published altitude over high terrain which led to a low altitude alert.