PA-31 Navajo/Chieftan/Mojave/T1040
Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Engineer; Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Flight Instructor
Flight Crew Last 90 Days 45; Flight Crew Total 17300; Flight Crew Type 1350
Distraction; Situational Awareness
Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Human Factors
Flying GPS/LPV RWY 13. Misread approach chart and saw alt from IF to FAF as 2000 ft. rather than charted 2400 ft. Approaching FAF tower informed me I was indicating 2000 ft. rather than 2400 ft. Shortly before this at about 2250 ft.; Avidyne IFD 440 had given me a yellow low altitude warning; but I assumed it was in error. Did not get a terrain warning since I remained at least 1200 ft. above terrain/obstacles below or ahead of me. I was tired and too comfortable flying into my home field though it was an approach I had not flown before. I should not have assumed the low altitude warning was an error; and instead rechecked the approach chart immediately. I held 2000 ft. till intercepting the GP (Glide Path).
PA-31 pilot reported descending below the published altitude during a GPS approach due to misreading the chart.