Narrative:

Approximately 8/10 of an hour into a late afternoon pleasure flight I noted loud noise over the headset with the anticollision lights on. I switched them off and turned back toward grand strand airport, approximately 40 mi up the coast. I contacted myr approach for flight following and was assigned a squawk. I proceeded up the coast and noted I was nearing myr AFB west/O a handoff. I attempted to reach the tower on VHF and noted the radio sounded weak. I noticed the ammeter at 0. Fault isolation led ot the knowledge that the alternator had failed and that the battery was already dead. I was now just south of the AFB and saw a twin slightly higher and 1 1/2 mi away, heading toward me on a left downwind. I turned left and down to avoid getting any closer. At this point I realized it was getting back quick and that I needed to get back to the field as soon as possible. I descended to 1000' MSL and skirted the MB AFB control zone offshore. (I did not have enough time to climb above the control zone.) I proceeded to grand strand directly and got a green light to land. I cannot overemphasize the need for a full INS x-chk, especially in a rental aircraft. If I had noted the 0 ammeter 10 mins earlier, I might have kept my radio power. Also I would like to emphasize the need for a good lookout even if on flight following. Lastly, adhering to airspace rules during an emergency must be tempered with judgement--landing at night west/O lights is a bit more difficult that see and avoid at the edge of the control zone!!

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Original NASA ASRS Text

Title: ALTERNATOR FAILED ON A RENTED SMA AND THE PLT REPORTER DID NOT NOTICE THE FAILURE UNTIL THE BATTERY WAS EXHAUSTED.

Narrative: APPROX 8/10 OF AN HR INTO A LATE AFTERNOON PLEASURE FLT I NOTED LOUD NOISE OVER THE HEADSET WITH THE ANTICOLLISION LIGHTS ON. I SWITCHED THEM OFF AND TURNED BACK TOWARD GRAND STRAND ARPT, APPROX 40 MI UP THE COAST. I CONTACTED MYR APCH FOR FLT FOLLOWING AND WAS ASSIGNED A SQUAWK. I PROCEEDED UP THE COAST AND NOTED I WAS NEARING MYR AFB W/O A HDOF. I ATTEMPTED TO REACH THE TWR ON VHF AND NOTED THE RADIO SOUNDED WEAK. I NOTICED THE AMMETER AT 0. FAULT ISOLATION LED OT THE KNOWLEDGE THAT THE ALTERNATOR HAD FAILED AND THAT THE BATTERY WAS ALREADY DEAD. I WAS NOW JUST S OF THE AFB AND SAW A TWIN SLIGHTLY HIGHER AND 1 1/2 MI AWAY, HDG TOWARD ME ON A LEFT DOWNWIND. I TURNED LEFT AND DOWN TO AVOID GETTING ANY CLOSER. AT THIS POINT I REALIZED IT WAS GETTING BACK QUICK AND THAT I NEEDED TO GET BACK TO THE FIELD ASAP. I DSNDED TO 1000' MSL AND SKIRTED THE MB AFB CTL ZONE OFFSHORE. (I DID NOT HAVE ENOUGH TIME TO CLB ABOVE THE CTL ZONE.) I PROCEEDED TO GRAND STRAND DIRECTLY AND GOT A GREEN LIGHT TO LAND. I CANNOT OVEREMPHASIZE THE NEED FOR A FULL INS X-CHK, ESPECIALLY IN A RENTAL ACFT. IF I HAD NOTED THE 0 AMMETER 10 MINS EARLIER, I MIGHT HAVE KEPT MY RADIO PWR. ALSO I WOULD LIKE TO EMPHASIZE THE NEED FOR A GOOD LOOKOUT EVEN IF ON FLT FOLLOWING. LASTLY, ADHERING TO AIRSPACE RULES DURING AN EMER MUST BE TEMPERED WITH JUDGEMENT--LNDG AT NIGHT W/O LIGHTS IS A BIT MORE DIFFICULT THAT SEE AND AVOID AT THE EDGE OF THE CTL ZONE!!

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.