Narrative:

I was PIC of a single engine VFR charter flight from tacoma narrows airport to yakima airport. While leveling off at 7500 ft approximately 35 mi southeast of the seattle VOR (101 degree radial), the alternator belt began wrapping itself around the spinner. Within 30 seconds, the belt was ripped in half and flew past the windscreen. I went through the emergency procedure for alternator failure and began to divert to the auburn airport. Within 2-3 mins after the belt failed, I was unable to communicate with ATC and was, in effect, flying through class B airspace without a clearance. Upon landing at the auburn airport, I telephoned seattle approach to explain what had happened. They said all was ok and no further information was needed. Although I did everything correctly as far as regulations are concerned, I feel that a more thorough inspection of the alternator belt prior to flight could have prevented 'emergency' actions. A complete preflight inspection was completed prior to the flight, however, I feel that a visual inspection of the belt for wear and tear would have allowed me to detect damage more so than a quick 'tug' on it to check for tension.

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Original NASA ASRS Text

Title: AN SMA CHARTER PLT WATCHED A TORN ALTERNATOR BELT FLY PAST THE WINDSCREEN WHILE IN CRUISE FLT. THIS EVENT AND THE SUBSEQUENT ELECTRICAL FAILURE LED TO AN IMMEDIATE DIVERSION TO AN ARPT UNDERLYING SEA CLASS B AIRSPACE WITHOUT COM WITH ATC. ACFT EQUIP PROB CRITICAL FLT DIVERTED.

Narrative: I WAS PIC OF A SINGLE ENG VFR CHARTER FLT FROM TACOMA NARROWS ARPT TO YAKIMA ARPT. WHILE LEVELING OFF AT 7500 FT APPROX 35 MI SE OF THE SEATTLE VOR (101 DEG RADIAL), THE ALTERNATOR BELT BEGAN WRAPPING ITSELF AROUND THE SPINNER. WITHIN 30 SECONDS, THE BELT WAS RIPPED IN HALF AND FLEW PAST THE WINDSCREEN. I WENT THROUGH THE EMER PROC FOR ALTERNATOR FAILURE AND BEGAN TO DIVERT TO THE AUBURN ARPT. WITHIN 2-3 MINS AFTER THE BELT FAILED, I WAS UNABLE TO COMMUNICATE WITH ATC AND WAS, IN EFFECT, FLYING THROUGH CLASS B AIRSPACE WITHOUT A CLRNC. UPON LNDG AT THE AUBURN ARPT, I TELEPHONED SEATTLE APCH TO EXPLAIN WHAT HAD HAPPENED. THEY SAID ALL WAS OK AND NO FURTHER INFO WAS NEEDED. ALTHOUGH I DID EVERYTHING CORRECTLY AS FAR AS REGS ARE CONCERNED, I FEEL THAT A MORE THOROUGH INSPECTION OF THE ALTERNATOR BELT PRIOR TO FLT COULD HAVE PREVENTED 'EMER' ACTIONS. A COMPLETE PREFLT INSPECTION WAS COMPLETED PRIOR TO THE FLT, HOWEVER, I FEEL THAT A VISUAL INSPECTION OF THE BELT FOR WEAR AND TEAR WOULD HAVE ALLOWED ME TO DETECT DAMAGE MORE SO THAN A QUICK 'TUG' ON IT TO CHK FOR TENSION.

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.