Aircraft equipment problem creates a navigation error in estimated times over en route check points.

Attributes
ACN	237861
Time
Date	199303
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : ewr
State Reference	NJ
Altitude	msl bound lower : 28000 msl bound upper : 28000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zny
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Navigation In Use	Other
Flight Phase	cruise other
Route In Use	enroute : other oceanic enroute : atlantic
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 265 flight time total : 13400 flight time type : 9000
ASRS Report	237861
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : critical non adherence : clearance non adherence : far other anomaly other anomaly other other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	none taken : unable
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

After takeoff from stx to ewr we accepted a rerte to dorado beacon and then A300 to bergh, etc to ewr. At our first check point navaids (duel omega) checked to be on course. After 45-60 mins, omegas began to diverge. We selected omega which appeared to be most correct and used that unit for navigation. We had no flight plan to check times since this was a rerte (extensive) as it turned out both omegas were 250 mi off course after a 3.5 hour flight. Reported times at check points were undoubtedly incorrect.

Original NASA ASRS Text

Title: ACFT EQUIP PROB CREATES A NAV ERROR IN ESTIMATED TIMES OVER ENRTE CHK POINTS.

Narrative: AFTER TKOF FROM STX TO EWR WE ACCEPTED A RERTE TO DORADO BEACON AND THEN A300 TO BERGH, ETC TO EWR. AT OUR FIRST CHK POINT NAVAIDS (DUEL OMEGA) CHKED TO BE ON COURSE. AFTER 45-60 MINS, OMEGAS BEGAN TO DIVERGE. WE SELECTED OMEGA WHICH APPEARED TO BE MOST CORRECT AND USED THAT UNIT FOR NAV. WE HAD NO FLT PLAN TO CHK TIMES SINCE THIS WAS A RERTE (EXTENSIVE) AS IT TURNED OUT BOTH OMEGAS WERE 250 MI OFF COURSE AFTER A 3.5 HR FLT. RPTED TIMES AT CHK POINTS WERE UNDOUBTEDLY INCORRECT.

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.