Pilot of DG300 sailplane discovers transponder inoperative due to low battery while over las class B...

Attributes
ACN	622937
Time
Date	200406
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : las.airport
State Reference	NV
Altitude	msl single value : 15000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Sail Plane
Operating Under FAR Part	Part 91
Flight Phase	cruise : enroute altitude change cruise : level
Flight Plan	None
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 71 flight time total : 690 flight time type : 150
ASRS Report	622937
Events
Anomaly	airspace violation : entry non adherence : far
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	other Other
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

Before transiting above las class B airspace or while above it (I'm not sure), I noticed that my (previously operating) transponder was not being interrogated (no flashing indicator). I further noticed that the ship's voltage was critically low. In response, I shut down all electrical devices except the variometer (to save remaining power for that -- the transponder appeared not to be working anyhow). To prevent this in the future, I will increase the battery capacity to allow extended transponder operation. I will also not overfly class B airspace if I know of an inoperative transponder before entering.

Original NASA ASRS Text

Title: PLT OF DG300 SAILPLANE DISCOVERS XPONDER INOP DUE TO LOW BATTERY WHILE OVER LAS CLASS B.

Narrative: BEFORE TRANSITING ABOVE LAS CLASS B AIRSPACE OR WHILE ABOVE IT (I'M NOT SURE), I NOTICED THAT MY (PREVIOUSLY OPERATING) XPONDER WAS NOT BEING INTERROGATED (NO FLASHING INDICATOR). I FURTHER NOTICED THAT THE SHIP'S VOLTAGE WAS CRITICALLY LOW. IN RESPONSE, I SHUT DOWN ALL ELECTRICAL DEVICES EXCEPT THE VARIOMETER (TO SAVE REMAINING PWR FOR THAT -- THE XPONDER APPEARED NOT TO BE WORKING ANYHOW). TO PREVENT THIS IN THE FUTURE, I WILL INCREASE THE BATTERY CAPACITY TO ALLOW EXTENDED XPONDER OP. I WILL ALSO NOT OVERFLY CLASS B AIRSPACE IF I KNOW OF AN INOP XPONDER BEFORE ENTERING.

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.