C172 pilot found during night flight that the rotating beacon and navigation lights caused a short i...

Attributes
ACN	536471
Time
Date	200201
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : g05.airport
State Reference	PA
Altitude	agl single value : 1000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tower : lfpg.tower
Operator	general aviation : personal
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	None
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : multi engine pilot : flight engineer pilot : cfi pilot : atp
Experience	flight time last 90 days : 5 flight time total : 8000 flight time type : 300
ASRS Report	536471
Person 2
Affiliation	other
Function	maintenance : technician
Events
Anomaly	aircraft equipment problem : less severe non adherence other
Independent Detector	aircraft equipment other aircraft equipment : amp meter other flight crewa
Resolutory Action	other
Consequence	other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

This was a night flight in visual conditions conducted under VFR. My rotating beacon and navigation lights were working fine when I departed westmoreland county airport (lbe), PA. Lbe is a controled airport. About 1/2 way to my destination, finleyville airport (G05), PA, I started to have a significant discharge in my electrical system as indicated by the ammeter. The discharge indication was pulsing in step with the flashing of my beacon. During my troubleshooting of the problem, I found that my beacon and navigation lights were causing the power drain. However, other electrical components including the landing light did not cause a drain. I, therefore, decided to turn off my beacon and navigation lights and continue the remaining 15 mins of flight using my landing light for recognition and avoidance. Callback conversation with reporter revealed the following information: reporter stated that he has not had the light problem fixed since he has not flown the aircraft. However, he has discussed the problem with mechanics and will have the problem fixed during the annual inspection. It is believed that there are wires shorting near the 2 switches for the 2 different lights.

Original NASA ASRS Text

Title: C172 PLT FOUND DURING NIGHT FLT THAT THE ROTATING BEACON AND NAV LIGHTS CAUSED A SHORT IN THE ELECTRICAL DRAW. WHEN TURNING THEM OFF, THE ELECTRICAL SHORT WENT AWAY. THEREFORE, HE TURNED ON THE LNDG LIGHT FOR THE 15 MIN REMAINDER OF THE FLT.

Narrative: THIS WAS A NIGHT FLT IN VISUAL CONDITIONS CONDUCTED UNDER VFR. MY ROTATING BEACON AND NAV LIGHTS WERE WORKING FINE WHEN I DEPARTED WESTMORELAND COUNTY ARPT (LBE), PA. LBE IS A CTLED ARPT. ABOUT 1/2 WAY TO MY DEST, FINLEYVILLE ARPT (G05), PA, I STARTED TO HAVE A SIGNIFICANT DISCHARGE IN MY ELECTRICAL SYS AS INDICATED BY THE AMMETER. THE DISCHARGE INDICATION WAS PULSING IN STEP WITH THE FLASHING OF MY BEACON. DURING MY TROUBLESHOOTING OF THE PROB, I FOUND THAT MY BEACON AND NAV LIGHTS WERE CAUSING THE PWR DRAIN. HOWEVER, OTHER ELECTRICAL COMPONENTS INCLUDING THE LNDG LIGHT DID NOT CAUSE A DRAIN. I, THEREFORE, DECIDED TO TURN OFF MY BEACON AND NAV LIGHTS AND CONTINUE THE REMAINING 15 MINS OF FLT USING MY LNDG LIGHT FOR RECOGNITION AND AVOIDANCE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT HE HAS NOT HAD THE LIGHT PROB FIXED SINCE HE HAS NOT FLOWN THE ACFT. HOWEVER, HE HAS DISCUSSED THE PROB WITH MECHS AND WILL HAVE THE PROB FIXED DURING THE ANNUAL INSPECTION. IT IS BELIEVED THAT THERE ARE WIRES SHORTING NEAR THE 2 SWITCHES FOR THE 2 DIFFERENT LIGHTS.

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.

C172 pilot found during night flight that the rotating beacon and navigation lights caused a short in the electrical draw. When turning them off, the electrical short went away. Therefore, he turned on the landing light for the 15 min remainder of the flight.