One of 2 of flight crew's omegas goes in error over 30 mi resulting in gross navigation error.

Attributes
ACN	314920
Time
Date	199508
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : bda
State Reference	FO
Altitude	msl bound lower : 33000 msl bound upper : 33000
Aircraft 1
Controlling Facilities	artcc : txkf
Operator	common carrier : air carrier
Make Model Name	B727-200
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	cruise other
Route In Use	enroute : atlantic enroute : on vectors enroute : other oceanic
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : commercial
Experience	flight time last 90 days : 130 flight time total : 8300 flight time type : 5000
ASRS Report	314920
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe non adherence : clearance other spatial deviation
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation other

Narrative:

Programmed omega units with filed routing. Distance to airport reference point checked out as did the coast out check using the rbv VOR, we never really flew our filed routing due to radar vectors and 'cleared directs.' number 2 omega was used to fly the aircraft and number 1 was backup. Cleared direct to targa intersection, when reporting targa ATC advised we were 33 NM northeast of the point. On ground at bda noted the distance to airport reference point showed 36 NM on the number 2 omega and the number 1 omega showed on airport. Callback conversation with reporter revealed the following information: the reporter stated he was flying the B727-200. Normally one omega would be in cross track angle and the other in distance and bearing with the HSI of the captain and first officer selected to their respective omega. In this case, the captain was selected to VOR DME of bermuda which had not come in range. The time from the known position to known error of 30 mi was about an hour.

Original NASA ASRS Text

Title: ONE OF 2 OF FLC'S OMEGAS GOES IN ERROR OVER 30 MI RESULTING IN GROSS NAV ERROR.

Narrative: PROGRAMMED OMEGA UNITS WITH FILED ROUTING. DISTANCE TO ARPT REFERENCE POINT CHKED OUT AS DID THE COAST OUT CHK USING THE RBV VOR, WE NEVER REALLY FLEW OUR FILED ROUTING DUE TO RADAR VECTORS AND 'CLRED DIRECTS.' NUMBER 2 OMEGA WAS USED TO FLY THE ACFT AND NUMBER 1 WAS BACKUP. CLRED DIRECT TO TARGA INTXN, WHEN RPTING TARGA ATC ADVISED WE WERE 33 NM NE OF THE POINT. ON GND AT BDA NOTED THE DISTANCE TO ARPT REFERENCE POINT SHOWED 36 NM ON THE NUMBER 2 OMEGA AND THE NUMBER 1 OMEGA SHOWED ON ARPT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED HE WAS FLYING THE B727-200. NORMALLY ONE OMEGA WOULD BE IN CROSS TRACK ANGLE AND THE OTHER IN DISTANCE AND BEARING WITH THE HSI OF THE CAPT AND FO SELECTED TO THEIR RESPECTIVE OMEGA. IN THIS CASE, THE CAPT WAS SELECTED TO VOR DME OF BERMUDA WHICH HAD NOT COME IN RANGE. THE TIME FROM THE KNOWN POS TO KNOWN ERROR OF 30 MI WAS ABOUT AN HR.

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.