Flight Crew Instrument; Flight Crew Private
Flight Crew Last 90 Days 59; Flight Crew Total 233; Flight Crew Type 233
Situational Awareness; Communication Breakdown
ATC Issue All Types; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Flight Crew Became Reoriented
Human Factors
I was being vectored onto the final approach course for the RNAV/GPS-15 approach into FCI. Was at assigned altitude 2600 feet. Received clearance '[tail number] turn right heading 160; maintain 2000 until established; cleared for the RNAV runway 15 straight in approach Richmond Executive'. I read back '120 maintain 2000 until established; cleared for the RNAV 15 Richmond Executive [tail number]'I intercepted the final approach course outside of SECOV (the FAF) and began my descent down to 2000 in VMC. Shortly thereafter; I received a 'low altitude' warning on my FMS and realized that I had descended below the 2200-foot minimum altitude for the segment between DOCEV and SECOV. At that point; I was VMC; cancelled IFR; and continued with a normal straight-in approach for landing.The particular controller speaks very quickly and it is sometimes hard to hear her above the background static. I listened back to the recording several times on liveatc.net and after slowing the recording down to 2/3 or normal speed; I can now hear that she said; 'Maintain two-thousand-six-hundred until established'. I read back 'maintain two-thousand until established' and was not corrected. In hindsight; I should have not descended below the segment's minimum altitude regardless and simply waited for the LPV vertical guidance needle to center while at 2600 feet.
GA pilot reported a communication breakdown with ATC led to an excursion from altitude while on approach to  Richmond Executive Airport.