Narrative:

ATC had asked 15 mins earlier to recycle transponder. Heard baltimore approach call but they could not hear our reply. Noticed discharge condition as transponder was not working I did not use lost communication code. Had handheld communication with charged batteries, and an adapter for headset. Unfortunately, I did not realize I could use the microphone with the headset. I, instead tried to talk into the handheld which was bypassed by the adapter jack being plugged in. Our original destination was hagerstown, (hgr) I decided to land at frederick, (fdk) because although I knew I had 2 1/2 hours of fuel remaining, the gauges said 'east' and I was not absolutely sure they were electrically driven. Consequently, we landed safely at frederick and contacted baltimore approach by phone. In addition I was not comfortable enough with the procedures on approaching a tower controled field without communication. Mechanics finding: alternator belt worn to point of not enough contact. Replaced belt. Annual done in oct 94? Perhaps the baltimore approach could have directed us to change direction if we could still hear them. Ie, right 20 degrees if lost communication and transponder and left 20 degrees if in need of assistance.

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Original NASA ASRS Text

Title: ALTERNATOR FAILURE WITH ASSOCIATED LOST COM AND INSTS. ACFT DIVERTED TO MORE SUITABLE ARPT.

Narrative: ATC HAD ASKED 15 MINS EARLIER TO RECYCLE XPONDER. HEARD BALTIMORE APCH CALL BUT THEY COULD NOT HEAR OUR REPLY. NOTICED DISCHARGE CONDITION AS XPONDER WAS NOT WORKING I DID NOT USE LOST COM CODE. HAD HANDHELD COM WITH CHARGED BATTERIES, AND AN ADAPTER FOR HEADSET. UNFORTUNATELY, I DID NOT REALIZE I COULD USE THE MIKE WITH THE HEADSET. I, INSTEAD TRIED TO TALK INTO THE HANDHELD WHICH WAS BYPASSED BY THE ADAPTER JACK BEING PLUGGED IN. OUR ORIGINAL DEST WAS HAGERSTOWN, (HGR) I DECIDED TO LAND AT FREDERICK, (FDK) BECAUSE ALTHOUGH I KNEW I HAD 2 1/2 HRS OF FUEL REMAINING, THE GAUGES SAID 'E' AND I WAS NOT ABSOLUTELY SURE THEY WERE ELECTRICALLY DRIVEN. CONSEQUENTLY, WE LANDED SAFELY AT FREDERICK AND CONTACTED BALTIMORE APCH BY PHONE. IN ADDITION I WAS NOT COMFORTABLE ENOUGH WITH THE PROCS ON APCHING A TWR CTLED FIELD WITHOUT COM. MECHS FINDING: ALTERNATOR BELT WORN TO POINT OF NOT ENOUGH CONTACT. REPLACED BELT. ANNUAL DONE IN OCT 94? PERHAPS THE BALTIMORE APCH COULD HAVE DIRECTED US TO CHANGE DIRECTION IF WE COULD STILL HEAR THEM. IE, R 20 DEGS IF LOST COM AND XPONDER AND L 20 DEGS IF IN NEED OF ASSISTANCE.

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.