GA pilot reported starting the approach early and thus setting off a terrain warning.

Attributes
ACN	1544103
Time
Date	201805
Local Time Of Day	1201-1800
Place
Locale Reference	IGQ.Airport
State Reference	IL
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Make Model Name	Small Aircraft Low Wing 2 Eng Retractable Gear
Operating Under FAR Part	Part 91
Flight Phase	Final Approach
Route In Use	Other RNAV Approach
Flight Plan	IFR
Person 1
Function	Single Pilot
Qualification	Flight Crew Instrument Flight Crew Private Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 12 Flight Crew Total 1000 Flight Crew Type 300
Events
Anomaly	Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Published Material / Policy Inflight Event / Encounter CFTT / CFIT

Narrative:

I was on a personal flight in IMC and simply misread the approach plate and then got confused. I descended to minimums before reaching the final approach fix and realized something was wrong once the terrain warning on the GNS430 went off. I used the obstacle screen on the 430 to make sure there were no conflicts between me and the airport; proceeded inbound; picked up the runway; and landed.I simply didn't brief the approach properly and then let myself get rushed and confused. It was such a short flight (15 minutes enroute); that I should have briefed it on the ground before departing.

Original NASA ASRS Text

Title: GA pilot reported starting the approach early and thus setting off a terrain warning.

Narrative: I was on a personal flight in IMC and simply misread the approach plate and then got confused. I descended to minimums before reaching the final approach fix and realized something was wrong once the terrain warning on the GNS430 went off. I used the obstacle screen on the 430 to make sure there were no conflicts between me and the airport; proceeded inbound; picked up the runway; and landed.I simply didn't brief the approach properly and then let myself get rushed and confused. It was such a short flight (15 minutes enroute); that I should have briefed it on the ground before departing.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.