Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Fatigue
Deviation / Discrepancy - Procedural Clearance; Flight Deck / Cabin / Aircraft Event Other / Unknown; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Human Factors
On arrival we were cleared for the approach. As PM I read back 'turn right 200 degrees maintain 2;000 till established cleared for the ILS approach'. Just outside the initial approach fix; ATC informed us of a low altitude alert and were told to climb back up to 3;000 feet. Once there we were re-cleared for the ILS approach. No further incidents.I would say that fatigue was the primary culprit. When we read back the clearance it should have seemed an unusual altitude to intercept at; as the minimum altitude at the IAF is 2;600 feet. Also when I received the clearance there was chatter on guard 121.5 which could have interfered with hearing our clearance correctly.
Aircraft descended below cleared altitude. Low altitude alert provided by ATC resulting in flight correcting to cleared altitude.