Flight Crew Instrument; Flight Crew Private
Flight Crew Last 90 Days 20; Flight Crew Total 1000; Flight Crew Type 940
Communication Breakdown; Training / Qualification; Confusion; Human-Machine Interface; Situational Awareness
Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Returned To Clearance
Human Factors
I was practicing a partial panel approach and used my backup steam gauges instead of the primary glass display. It has been awhile since I used my backup instruments. I misread the altimeter by 1;000 ft. and got lower than intended. My safety pilot did not call out the issue until I dropped to around 500 ft. I've only switched to a glass display 2 years ago. The lesson I learned here is that remaining competent on older backup instruments is a skill that needs to be exercised regularly.
AA5 pilot reported misinterpreting his altimeter; resulting in a deviation from his assigned altitude.