Small aircraft drifts off course when power loss results in erroneous VOR signals.

Attributes
ACN	86440
Time
Date	198802
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : ind
State Reference	IN
Altitude	msl bound lower : 8000 msl bound upper : 8000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid
Operator	general aviation : instructional
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Retractable Gear
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : commercial pilot : instrument
Experience	flight time last 90 days : 30 flight time total : 350 flight time type : 35
ASRS Report	86440
Person 2
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	non adherence : clearance other anomaly other other spatial deviation
Independent Detector	other controllera other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Lost all VOR, DME, D/G, navigation while in IFR and ice. Cause: master switch only 1/2 on and alternator not on. Cause: my hand must have bumped the switch during turbulence during takeoff from okk. Discovered: ATC told me I was 12 mi off course and heading. Callback conversation with reporter revealed the following: reporter never did notice the alternator inoperative light and did finally notice VOR 'off' flags just about the same time that ARTCC called him about his position. When asked about whether or not the aircraft was equipped with an alternator inoperative light, reporter showed signs that he is not very familiar with the aircraft. He did finally remember that the light was located on the annunciator panel.

Original NASA ASRS Text

Title: SMA DRIFTS OFF COURSE WHEN POWER LOSS RESULTS IN ERRONEOUS VOR SIGNALS.

Narrative: LOST ALL VOR, DME, D/G, NAV WHILE IN IFR AND ICE. CAUSE: MASTER SWITCH ONLY 1/2 ON AND ALTERNATOR NOT ON. CAUSE: MY HAND MUST HAVE BUMPED THE SWITCH DURING TURB DURING TKOF FROM OKK. DISCOVERED: ATC TOLD ME I WAS 12 MI OFF COURSE AND HDG. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR NEVER DID NOTICE THE ALTERNATOR INOP LIGHT AND DID FINALLY NOTICE VOR 'OFF' FLAGS JUST ABOUT THE SAME TIME THAT ARTCC CALLED HIM ABOUT HIS POS. WHEN ASKED ABOUT WHETHER OR NOT THE ACFT WAS EQUIPPED WITH AN ALTERNATOR INOP LIGHT, RPTR SHOWED SIGNS THAT HE IS NOT VERY FAMILIAR WITH THE ACFT. HE DID FINALLY REMEMBER THAT THE LIGHT WAS LOCATED ON THE ANNUNCIATOR PANEL.

Data retrieved from NASA's ASRS site as of August 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.