Narrative:

Departed aus VFR to T05, climbed to 7500 ft. Later, ceiling 5000 ft developed on route near corpus and corpus approach handed me to valley approach who gave me IFR clearance to descend to 1500 ft over gulf. Did not break out, so vectored to hrl for localizer back course approach. Broke out high over airport and stupidly asked permission to continue VFR to T05. 1/2 way there (5 mi), GPS batteries failed, ceiling and visibility lowered, lost radio contact with valley approach because of low altitude, and was unsure of position. Finally found T05 by dead reckoning and made terrible crosswind landing. I should have filed IFR to begin with. Made a poor decision not to full stop land at hrl where I could have plotted a course to T05 by VOR navigation in addition to GPS and could have changed GPS batteries I knew were low. Also, not very familiar with localizer back course approachs and did a poor job of altitude control. Never fully depend on hand-held GPS for position and keep fresh batteries installed. Never change plans after difficult and unfamiliar approach. Get more practice and instruction in localizer back course approachs.

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Original NASA ASRS Text

Title: PLT OF AN MO-20J DESCRIBES HIS ENTRY PROC INTO A NON TWR ARPT, T05, TX. HE HAD NOT FILED AN IFR FLT PLAN AND ATTEMPTED A VFR FLT USING A GPS WITH 'TIRED' BATTERIES. HE WAS NOT HAPPY WITH HIS PERFORMANCE.

Narrative: DEPARTED AUS VFR TO T05, CLBED TO 7500 FT. LATER, CEILING 5000 FT DEVELOPED ON RTE NEAR CORPUS AND CORPUS APCH HANDED ME TO VALLEY APCH WHO GAVE ME IFR CLRNC TO DSND TO 1500 FT OVER GULF. DID NOT BREAK OUT, SO VECTORED TO HRL FOR LOC BACK COURSE APCH. BROKE OUT HIGH OVER ARPT AND STUPIDLY ASKED PERMISSION TO CONTINUE VFR TO T05. 1/2 WAY THERE (5 MI), GPS BATTERIES FAILED, CEILING AND VISIBILITY LOWERED, LOST RADIO CONTACT WITH VALLEY APCH BECAUSE OF LOW ALT, AND WAS UNSURE OF POS. FINALLY FOUND T05 BY DEAD RECKONING AND MADE TERRIBLE XWIND LNDG. I SHOULD HAVE FILED IFR TO BEGIN WITH. MADE A POOR DECISION NOT TO FULL STOP LAND AT HRL WHERE I COULD HAVE PLOTTED A COURSE TO T05 BY VOR NAV IN ADDITION TO GPS AND COULD HAVE CHANGED GPS BATTERIES I KNEW WERE LOW. ALSO, NOT VERY FAMILIAR WITH LOC BACK COURSE APCHS AND DID A POOR JOB OF ALT CTL. NEVER FULLY DEPEND ON HAND-HELD GPS FOR POS AND KEEP FRESH BATTERIES INSTALLED. NEVER CHANGE PLANS AFTER DIFFICULT AND UNFAMILIAR APCH. GET MORE PRACTICE AND INSTRUCTION IN LOC BACK COURSE APCHS.

Data retrieved from NASA's ASRS site as of July 2007 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.