Flight Crew Instrument; Flight Crew Multiengine
Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Returned To Clearance
Environment - Non Weather Related; Human Factors; Procedure
Altitude Excursion. I was operating with a company instructor pilot.  We were on an IFR flight plan operating in the vicinity of ZZZ.  We had requested a practice RNAV XX instrument approach into ZZZ and were cleared direct to ZZZZZ; maintain 2;000 feet until ZZZZZ; cleared for the RNAV XX into ZZZ.  We were descending out of altitude (above 2;000 feet) and I was wanting to practice cockpit automation.  The minimums for the approach were already programmed in the FMS; so I requested we set the minimums in the altitude selector and got approval from the IP.  I selected LPV minimums with the altitude selector and continued the descent.  At 1;700 feet MSL; I realized that we did not capture 2;000 feet MSL and took appropriate action to return to 2;000 feet.  I'm not absolutely sure; but I believe we may have descended to 1;600 feet before arresting the descent and climbed back to the assigned 2;000 feet.  The approach was then completed normally.  Analysis and debrief revealed that an inadequate brief of the approach with the intended use of automation and a confirmation of correct programming of the automation had not taken place.  The vertical descent mode of the AFCS had been left in VS as opposed to the required selection of the VNV function.  The VNV function would have held us to 2;000 feet while VS only looks at the altitude selector for level off.  Supplemental factors:Do to COVID-19; our flight schedule had been greatly reduced and this was my first day of flying in [X] weeks.   At the time of the altitude excursion; I had been on duty for [X] hours and had flown close to five of those hours.
Pilot reported experiencing an altitude deviation and cited lack of flying due to the COVID-19 pandemic as a contributing factor.