Narrative:

We departed in VFR conditions. We were in good IMC (smooth ride) when the alternator failed. Center immediately granted my request to return to my departure airport about 100 miles away. After my course reversal center inquired about the reason for the return. I reported the alternator failure and asked about cloud bases in the area. Center reported I was near an enroute airport and the ceiling there was 2700. The decision was made to land at that airport. We landed safely. Center was most helpful and professional; guiding us to the airport and obtaining landing clearance from the tower. We were most grateful for this help. Tower was also most helpful. Thanks again to both. The problem with these real emergencies is that; unlike in a training situation; you just don't expect them. I got a little busier during this than I would have expected. As a flight instructor; I am disappointed that I disregarded a clue from the stormscope that a problem was developing. A pie shaped wedge of 'strikes' extended from our right to the edge of the map. When I zoomed in; it appeared to be more than 10 miles away; so I just took unwarranted comfort that we were not going that way. Another possible clue was that the portable GPS496 'lost external power' at one point; but its plug appeared loose and the problem went away when I pushed the plug in. I was focused on our approach into our filed destination; still a couple of hours away; because we needed the visibility to increase by a quarter mile to meet minimums there; I had expected that increase to come in the next weather report; but it did not. When the GPS496 reported power loss a second time (and the plug was firmly in); I noticed the the ammeter was showing a discharge condition; and realized the alternator was failing. Interestingly through the remainder of the flight; the ammeter would sometimes show a charging condition. In retrospect; I am disappointed that I did not request a real approach into my diversionary airport; but with the reported ceiling; I did not see the need for that. Sure enough; we could see the ground (through)small clouds at about that altitude; but we did not have visual contact with the runway until at 1000 MSL. We happened to arrive as the ceiling was lowering rapidly.

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Original NASA ASRS Text

Title: A C177's alternator failed in flight at 7000 feet in IMC. ATC was informed and the reporter turned back to the departure airport 100 miles away. ATC advised of a closer airport which the reporter accepted.

Narrative: We departed in VFR Conditions. We were in good IMC (smooth ride) when the alternator failed. Center immediately granted my request to return to my departure airport about 100 miles away. After my course reversal Center inquired about the reason for the return. I reported the alternator failure and asked about cloud bases in the area. Center reported I was near an enroute airport and the ceiling there was 2700. The decision was made to land at that airport. We landed safely. Center was most helpful and professional; guiding us to the airport and obtaining landing clearance from the Tower. We were most grateful for this help. Tower was also most helpful. Thanks again to both. The problem with these real emergencies is that; unlike in a training situation; you just don't expect them. I got a little busier during this than I would have expected. As a flight instructor; I am disappointed that I disregarded a clue from the Stormscope that a problem was developing. A pie shaped wedge of 'strikes' extended from our right to the edge of the map. When I zoomed in; it appeared to be more than 10 miles away; so I just took unwarranted comfort that we were not going that way. Another possible clue was that the portable GPS496 'lost external power' at one point; but its plug appeared loose and the problem went away when I pushed the plug in. I was focused on our approach into our filed destination; still a couple of hours away; because we needed the visibility to increase by a quarter mile to meet minimums there; I had expected that increase to come in the next weather report; but it did not. When the GPS496 reported power loss a second time (and the plug was firmly in); I noticed the the ammeter was showing a discharge condition; and realized the alternator was failing. Interestingly through the remainder of the flight; the ammeter would sometimes show a charging condition. In retrospect; I am disappointed that I did not request a real approach into my diversionary airport; but with the reported ceiling; I did not see the need for that. Sure enough; we could see the ground (through)small clouds at about that altitude; but we did not have visual contact with the runway until at 1000 MSL. We happened to arrive as the ceiling was lowering rapidly.

Data retrieved from NASA's ASRS site as of April 2012 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.