Small Aircraft; Low Wing; 1 Eng; Retractable Gear
Flight Crew Instrument; Flight Crew Private
Flight Crew Last 90 Days 43; Flight Crew Total 495; Flight Crew Type 185
Situational Awareness; Confusion; Distraction
Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Human Factors
I was enroute via the RNAV GPS 31L approach into Hillsboro; Oregon (KHIO). I was between FLOWR and NNIKE when I descended below the minimum segment altitude of 4;000 feet and descended to 2;000 feet. The Tower Controller appropriately and helpfully advised me of my altitude deviation and I corrected it. The conditions were VMC with flight visibility between 7 and 10 miles. The skies were either clear above me or the ceiling was more than 6;000-7;000 feet. I believe I descended below minimum altitude because I grew complacent due to the good conditions and visibility. Instead of knowing that I was between FLOWR and NNIKE where the minimum altitude was 4;000 feet; I believed I was between NNIKE and INTLL where the minimum altitude is 2;000 feet.I can prevent the recurrence of this problem by rigorously briefing each approach and maintaining accurate positional awareness.
The pilot of a small aircraft descended below the published approach minimum altitude due to VFR conditions; complacency and situational awareness.