A Corporate flight crew reported they descended below their assigned altitude and received a Low Altitude Alert from ATC.
Synopsis
A Corporate flight crew reported they descended below their assigned altitude and received a Low Altitude Alert from ATC.
Narrative
I was pilot monitoring; the PIC was pilot flying. Departing from ZZZ we encountered gear issues on takeoff. Left main gear did not indicate up and locked. We let approach know of our issue; troubleshooted and was eventually able to get all landing gear up and locked. Decided to continue to destination of ZZZ1. There were no abnormalities in the flight during cruise. During descent; we were given radar vectors and step down altitudes. When given a heading; we thought we heard a descent from our current altitude of 9000 feet but did not hear the altitude. I attempted to contact approach to confirm our new altitude at least 2 times and was not able to get a response. Eventually we were given a different heading; where I asked again if approach wanted a different altitude; which they did advise. We continued our descent with the autopilot on while I ran our final approach and landing checklists. While working through the checklist; I noticed our landing gear was not coming down as fast as usual which took my attention away from scanning other things in the aircraft; most importantly was altitude in this case. I let my captain know that our gear was slow to extend and it ended up taking his attention also. During this time; while I was dealing with the gear issue and running checklists; my captain set 4;000 feet after he thought he heard that requested by ATC but did not verify the altitude with me (we always have confirmed altitudes in the past); making me unaware of the low altitude set in the aircraft. This is when our altitude ended up getting too low. Approach called; which made me look up and notice our altitude was too low; both visually outside we looked low as well as our indicated altitude was too low at the time. Approach gave us a low altitude alert and requested a climb to 5;500ft I called for a climb; and we climbed immediately up to the requested altitude. The gear ended up coming down properly; however it took much longer than anticipated. That paired with the gear up issues we had departing ZZZ led to our distraction and low altitude. Due to the busyness of this critical phase of flight; I failed to inform approach of our gear issues after regaining altitude. Approach made us aware of the location to the airport; which we responded we had in sight. We were given cleared visual approach XXR. While on final for XXR; ZZZ1 tower told us there was a coyote on the runway and ordered for us to go around. We executed the go around and ZZZ1 approach set us up for another attempt at the runway. Landed with no issues. ZZZ1 ground alerted us to the possible pilot deviation with phone number once we were parked at the FBO. This was an unfortunate situation of getting distracted by a mechanical abnormality in the flight deck which was avoidable with better communication and scanning. My role as pilot monitoring requires me to stay vigilant during all phases of flight and I have learned the importance of continuing to monitor all aspects of flight regardless of the situation. After a lengthy debrief with my Captain; discussing the issues we encountered and how to handle them better in the future; I have come out of this experience with better knowledge and understanding of abnormal situations such as this and am certain this will not happen again.
Second reporter narrative
We were on descent into ZZZ. When at 9;000'; approach assigned a new heading and altitude. We were not clear of the altitude and the co-pilot asked again twice. Finally; the third time got a response. I thought I heard 4;000'. At the time; we were dealing with a maintenance issue. The landing gear was coming down very slow. We had a gear up issue leaving ZZZ1. Both of us turned our attention to the problem. I should have verified the altitude with the co-pilot when setting; but did not. Usually; this is something we do regardless of who is flying. When approach came on the radio and assigned us 5;500'; we immediately made the correction. The other pilot and I debriefed after landing. We should have informed approach of the maintenance issue. To prevent a similar incident in the future; we discussed having one of us always aviating; navigating and communicating while the other deals with the issue; whether it is maintenance or something else. That was our lesson learned. There will not be an incident like this again.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.