PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Commercial
Flight Crew Last 90 Days 50; Flight Crew Total 270; Flight Crew Type 270
Situational Awareness; Distraction; Confusion; Troubleshooting
Aircraft Equipment Problem Less Severe; Deviation - Altitude Crossing Restriction Not Met; Deviation - Altitude Undershoot; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT
General None Reported / Taken
Human Factors; Software and Automation
Vectored to ILS/LOC 10 into UES; had base of clouds around 2;300 AGL; the at or above altitude for our final approach fix. I entered flight plan into top Garmin unit and had user error. I was expecting G430's to be in cooperation with one another after entering flight plan and programming. In the moment forgetting this morning we encountered an updating information error in one of our G430's. While being vectored; I spent too much time trying to problem solve why my G430's weren't in unison rather than paying attention to my altitude. I flew below my final approach fix altitude before arriving at way point. At this time; we were below the clouds and I had visual of Runway 10. I noticed my glide slope was well above me and then re-looked at my plate realizing my error. The problem was in my scan; which I had just finished instructing my student about in our lesson. I spent too much time fixated on my attitude indicator and GPS that I failed to realize my glide slope was gradually raising above me. A very avoidable error.
GA Flight Instructor reported being distracted while trying to troubleshoot a GPS information error resulting in an altitude deviation and CFTT during final approach to UES airport.