DA40 Diamond Star
Flight Crew Commercial; Flight Crew Instrument; Flight Crew Rotorcraft
Flight Crew Last 90 Days 58; Flight Crew Total 557; Flight Crew Type 417
Situational Awareness; Distraction
Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Flight Deck / Cabin / Aircraft Event Other / Unknown; Inflight Event / Encounter CFTT / CFIT; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented; Flight Crew Returned To Clearance; Flight Crew Took Evasive Action
Human Factors; Weather
Today I was flying to ZZZ on IFR flight plan. Most of the trip with IMC. As I approached ZZZ I requested ILS 18 and was told to expect this. Due to [another aircraft] ahead of me; I was asked to hold at ZZZZZ. I performed 2 holding patterns at 4;000 feet before I was cleared for the ILS approach. I was total IMC during this time and the very helpful ATC man told me the [aircraft ahead of me] had busted out at 1;200 feet. I crossed the initial fix I believe at 2;600 (was supposed to be at 3;000 feet) and began descending on the approach. I thought I was behind on the approach due to holding at 4;000 feet; so I descended at 500 feet/min at the same time my Garmin 530 that I was tracking; was not working properly due to the multiple hold legs. I was fixing this during the descent as to stay on my heading. I got ahead of the aircraft and then my terrain warning came on and I immediately stopped my descent and went back up to 2;000 feet. I believe I was down to 1;500 feet. Also simultaneously ATC informed me of my low altitude. I stayed at 2;000 feet until the localizer came back in and descended for a landing. I was asked to call [TRACON] once on the ground during this approach while still IMC due to a pilot altitude discrepancy. As I came out of the clouds about 1;000 feet I completed the landing; shut down and called [TRACON] in the ZZZ FBO and further explained the situation.I realize there was more than one issue which led to this mistake. I am the PIC and take responsibility and understand the importance of being in control of my aircraft. The issues that effected my mistake were single pilot IMC; rain; wind; mild turbulence; G530 not responding due to multiple holds; and basically getting ahead of the aircraft and the approach. I have also had issues with my Mode C on my transponder in the past and this is being checked [very soon.] This will be something I am more aware of and possibly rethink taking this flight in the future if weather conditions are the same. Thank you for your time.
DA-40 pilot reported an early descent in IMC led to a low altitude alert.