C414 pilot experiences GPS failure while navigating direct zfp at 8;000 ft resulting in a navigation...

Attributes
ACN	1061202
Time
Date	201301
Local Time Of Day	0601-1200
Place
Locale Reference	ZMA.ARTCC
State Reference	FL
Environment
Flight Conditions	IMC
Light	Dawn
Aircraft 1
Make Model Name	Chancellor 414A / C414
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	GPS & Other Satellite Navigation
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 50 Flight Crew Total 26000 Flight Crew Type 60
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Clearance Deviation - Track / Heading All Types

Narrative:

IFR clearance received from miami center: direct to freeport VOR (zfp) BR63V to mrlin intersection; etc. Maintain 8;000 ft. Told to report over zfp VOR (mia center radar coverage is spotty in the vicinity of zfp VOR). While proceeding to zfp using GPS the GPS set unlocked (lost signal). I determined my location as 7 miles south of zfp VOR and was about to call ATC and advise them of our location when ATC called me and advised that I was 7 miles south of zfp instead of over zfp as cleared. My apologies were made to ATC and he gave me a 325 degree heading to intercept BR63V westbound out of zfp and shortly thereafter a clearance direct to mrlin intersection. Rest of flight was flown as cleared. Problem was caused by a very weak warning light on the GPS unit that is almost impossible to see in the bright light of a daytime flight. Avionics man is checking out the GPS problem.

Original NASA ASRS Text

Title: C414 pilot experiences GPS failure while navigating direct ZFP at 8;000 FT resulting in a navigational error that is detected by ATC. The GPS failure warning light was on but too faint to be seen readily in the bright daylight.

Narrative: IFR clearance received from Miami Center: Direct to Freeport VOR (ZFP) BR63V to MRLIN Intersection; etc. Maintain 8;000 FT. Told to report over ZFP VOR (MIA Center radar coverage is spotty in the vicinity of ZFP VOR). While proceeding to ZFP using GPS the GPS set unlocked (lost signal). I determined my location as 7 miles south of ZFP VOR and was about to call ATC and advise them of our location when ATC called me and advised that I was 7 miles south of ZFP instead of over ZFP as cleared. My apologies were made to ATC and he gave me a 325 degree heading to intercept BR63V westbound out of ZFP and shortly thereafter a clearance direct to MRLIN Intersection. Rest of flight was flown as cleared. Problem was caused by a very weak warning light on the GPS unit that is almost impossible to see in the bright light of a daytime flight. Avionics man is checking out the GPS problem.

Data retrieved from NASA's ASRS site as of July 2013 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.

C414 pilot experiences GPS failure while navigating direct zfp at 8;000 ft resulting in a navigational error that is detected by ATC. The GPS failure warning light was on but too faint to be seen readily in the bright daylight.