<< >> NASA ASRS Report 172597, February 1991

Spiking of current from alternators in small transport twin atx caused LORAN to reset year and variation to change and show intxns and fixes in flagrant error.

Attributes
ACN	172597
Time
Date	199102
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : ssi
State Reference	GA
Altitude	msl bound lower : 3000 msl bound upper : 3000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : sav
Operator	common carrier : air taxi
Make Model Name	Small Aircraft, Low Wing, 2 Eng, Retractable Gear
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air taxi
Function	flight crew : single pilot
Qualification	pilot : cfi pilot : instrument pilot : commercial
Experience	flight time last 90 days : 70 flight time total : 1385 flight time type : 75
ASRS Report	172597
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : less severe other spatial deviation
Independent Detector	other other : unspecified cockpit
Resolutory Action	flight crew : became reoriented
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Airborne from tbr radar to sav around bulldog restr area (southwest of sav), after steering clear of the restr area, cleared direct to broun intersection. Ended 7-10 NM left of direct route. Aircraft alternators were beginning to show indications of failure. Questioned several times by sav approach as to my intentions. The resulting voltage spikes reset the aircraft LORAN. It set LORAN yr from 1991 to 1999. The local var is 4W and variation of 1999 was 17W, which put broun intersection and aircraft out to sea. Alternators were checked and found to be faulty. LORAN was reset. I'm sure a great # of LORAN users have forgotten that on some lorans each new yr, such as 1991, needs to be set in for proper navigation.

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Original NASA ASRS Text

Title: SPIKING OF CURRENT FROM ALTERNATORS IN SMT TWIN ATX CAUSED LORAN TO RESET YEAR AND VARIATION TO CHANGE AND SHOW INTXNS AND FIXES IN FLAGRANT ERROR.

Narrative: AIRBORNE FROM TBR RADAR TO SAV AROUND BULLDOG RESTR AREA (SW OF SAV), AFTER STEERING CLR OF THE RESTR AREA, CLRED DIRECT TO BROUN INTXN. ENDED 7-10 NM LEFT OF DIRECT RTE. ACFT ALTERNATORS WERE BEGINNING TO SHOW INDICATIONS OF FAILURE. QUESTIONED SEVERAL TIMES BY SAV APCH AS TO MY INTENTIONS. THE RESULTING VOLTAGE SPIKES RESET THE ACFT LORAN. IT SET LORAN YR FROM 1991 TO 1999. THE LCL VAR IS 4W AND VARIATION OF 1999 WAS 17W, WHICH PUT BROUN INTXN AND ACFT OUT TO SEA. ALTERNATORS WERE CHKED AND FOUND TO BE FAULTY. LORAN WAS RESET. I'M SURE A GREAT # OF LORAN USERS HAVE FORGOTTEN THAT ON SOME LORANS EACH NEW YR, SUCH AS 1991, NEEDS TO BE SET IN FOR PROPER NAV.

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.