Falcon 2000 Flight Crew reported an altitude deviation due to a communication breakdown regarding an ATC revised descent clearance. The flight crew read back an erroneous descent clearance which was corrected by ATC.
Synopsis
Falcon 2000 Flight Crew reported an altitude deviation due to a communication breakdown regarding an ATC revised descent clearance. The flight crew read back an erroneous descent clearance which was corrected by ATC.
Narrative
I was pilot flying. We were proceeding on the ZZZZZ arrival into ZZZ. We were in VMC conditions in the vicinity of ZZZ1 talking to ZZZ Control. The arrival states cross ZZZ1 below 13000. ZZZZZ has a hard crossing altitude of 8000. The Controller states we were given instructions to descend to 13000; then direct to ZZZZZ; cross 5 miles East of ZZZZZ at 8000. Direct ZZZZZ takes us off the arrival route. We read back what we thought were our instructions; cross ZZZZZ at 5000 and that was rogered. A short time later we were issued a low altitude alert and climbed to 8000. We then were switched to the next sector and continued our arrival without incident. I remember the frequency being busy; and there were similar call signs. We were both sure we had been cleared to 5000; and since we were in VMC and not 'descending via' the arrival; there did not seem to be anything wrong with descending to 5000. Nothing more was said to us.We thought we were cleared direct to ZZZZZ and descend to five thousand ft. We rogered that clearance and were not contradicted. While we were wrong; we could clearly see the terrain and since we were off the STAR routing we saw nothing wrong. If we had heard the Controller more clearly; or if they had corrected our read back; as mentioned; the frequency was busy and evidently we missed the first instruction; to climb to 8000. At the start of this event we heard 'Direct to ZZZZZ; out of 'Cross 5 miles East of ZZZZZ at 8000;' and read back 'Cross ZZZZZ at 5000;' or words to that effect. I won't try to justify that but evidently that is what happened."
Second reporter narrative
Flying ZZZZZ arrivals into ZZZ; ZZZ ATC cleared Aircraft X to an altitude of 13000; the aircraft was on arrival outside of ZZZ1. A few moments later the Controller cleared Aircraft X direct to ZZZZZ off the arrival and to cross ZZZZZ; 5 miles before ZZZZZ at 5000 ft. was read back to Controller and confirmed by the other pilot. A few moments later the Controller notified Aircraft X of an altitude alert and was given clearance to climb to 8000 ft; which we did quickly. At no time was the aircraft in danger and the weather conditions were VFR. Nothing else was said and Aircraft X continued to ZZZ. I was a pilot not flying.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.