C172 pilot had generator failure.

Attributes
ACN	444214
Time
Date	199907
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	navaid : dbq.vortac
State Reference	IA
Altitude	msl single value : 9500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zau.artcc
Operator	general aviation : personal
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Navigation In Use	other vortac
Flight Phase	cruise : level
Flight Plan	None
Person 1
Affiliation	other
Function	flight crew : single pilot oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 225 flight time total : 10600 flight time type : 13
ASRS Report	444214
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa
Resolutory Action	flight crew : declared emergency flight crew : diverted to another airport flight crew : landed as precaution
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

Newly purchased aircraft, returning home from place of purchase, 'volts' light came on. Due to lack of experience in aircraft (.6 demonstration flight, .6 chkout) it took me several mins to sort things out. I elected to land at dbq for maintenance, but realized about 20 mi out that battery voltage was dropping at a rate such that my radio might quit, so I declared an emergency, and in fact the radio did quit about 10 mi out, even though all non-essential electrical equipment had been secured earlier. Had I been more 'up to speed' on the C172 electrical system I think I could have idented the problem (alternator failure) earlier. I also could have better estimated my remaining battery power in mins and could have chosen a divert field within range of my remaining battery life. The bulk of my flight time is part 121 airline and my recent GA experience has been 6-8 hours per yr. This was also a factor. Also, I used valuable time struggling with the GPS in locating a suitable airport because the GPS was new to me. Bottom line, I was able to compensate for my minimum familiarity with the aircraft with my considerable aviation experience. I think that such a minimal chkout combined with a low-time pilot might have had a less satisfactory conclusion.

Original NASA ASRS Text

Title: C172 PLT HAD GENERATOR FAILURE.

Narrative: NEWLY PURCHASED ACFT, RETURNING HOME FROM PLACE OF PURCHASE, 'VOLTS' LIGHT CAME ON. DUE TO LACK OF EXPERIENCE IN ACFT (.6 DEMO FLT, .6 CHKOUT) IT TOOK ME SEVERAL MINS TO SORT THINGS OUT. I ELECTED TO LAND AT DBQ FOR MAINT, BUT REALIZED ABOUT 20 MI OUT THAT BATTERY VOLTAGE WAS DROPPING AT A RATE SUCH THAT MY RADIO MIGHT QUIT, SO I DECLARED AN EMER, AND IN FACT THE RADIO DID QUIT ABOUT 10 MI OUT, EVEN THOUGH ALL NON-ESSENTIAL ELECTRICAL EQUIP HAD BEEN SECURED EARLIER. HAD I BEEN MORE 'UP TO SPD' ON THE C172 ELECTRICAL SYS I THINK I COULD HAVE IDENTED THE PROB (ALTERNATOR FAILURE) EARLIER. I ALSO COULD HAVE BETTER ESTIMATED MY REMAINING BATTERY PWR IN MINS AND COULD HAVE CHOSEN A DIVERT FIELD WITHIN RANGE OF MY REMAINING BATTERY LIFE. THE BULK OF MY FLT TIME IS PART 121 AIRLINE AND MY RECENT GA EXPERIENCE HAS BEEN 6-8 HRS PER YR. THIS WAS ALSO A FACTOR. ALSO, I USED VALUABLE TIME STRUGGLING WITH THE GPS IN LOCATING A SUITABLE ARPT BECAUSE THE GPS WAS NEW TO ME. BOTTOM LINE, I WAS ABLE TO COMPENSATE FOR MY MINIMUM FAMILIARITY WITH THE ACFT WITH MY CONSIDERABLE AVIATION EXPERIENCE. I THINK THAT SUCH A MINIMAL CHKOUT COMBINED WITH A LOW-TIME PLT MIGHT HAVE HAD A LESS SATISFACTORY CONCLUSION.

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.