Flight crew of large transport on oceanic route navigating with double omegas strayed off course.

Attributes
ACN	124599
Time
Date	198910
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : ecg
State Reference	NC
Altitude	msl bound lower : 29000 msl bound upper : 29000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zny artcc : zhu
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	cruise other
Route In Use	enroute : other oceanic
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : flight engineer pilot : cfi
Experience	flight time last 90 days : 70 flight time total : 8600 flight time type : 700
ASRS Report	124599
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	non adherence : far non adherence : clearance other anomaly other other spatial deviation
Independent Detector	other controllera
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation
Situations
Navigational Aid	Unspecified

Narrative:

While cruising between coran and bacus using dual omega, the omegas began to split. Bacus is defined by a radial off elizabeth city, but elizabeth city was off the air. The arrival times on the flight plan had been met within 1 min all the way up. So at the ETA to bacus we were at bacus according to #2 omega. We turned to elizabeth city and shortly were in contact with radar. Radar told us we were 30 mi north in a hot warning area and issued a vector back to the corridor to elizabeth city. The captain and I both feel the omega was not at fault due to normal operation both before and after this incident. There was a NOTAM for polar path disturbances and we feel this may have affected the unit. Elizabeth city being off the air was certainly a contributing factor, in fact, for this type of flying I feel it is inappropriate to have been cleared on an airway that is solely predicated on an out of service VOR (omega is not normally used for navigation over land).

Original NASA ASRS Text

Title: FLT CREW OF LGT ON OCEANIC ROUTE NAVIGATING WITH DOUBLE OMEGAS STRAYED OFF COURSE.

Narrative: WHILE CRUISING BETWEEN CORAN AND BACUS USING DUAL OMEGA, THE OMEGAS BEGAN TO SPLIT. BACUS IS DEFINED BY A RADIAL OFF ELIZABETH CITY, BUT ELIZABETH CITY WAS OFF THE AIR. THE ARR TIMES ON THE FLT PLAN HAD BEEN MET WITHIN 1 MIN ALL THE WAY UP. SO AT THE ETA TO BACUS WE WERE AT BACUS ACCORDING TO #2 OMEGA. WE TURNED TO ELIZABETH CITY AND SHORTLY WERE IN CONTACT WITH RADAR. RADAR TOLD US WE WERE 30 MI N IN A HOT WARNING AREA AND ISSUED A VECTOR BACK TO THE CORRIDOR TO ELIZABETH CITY. THE CAPT AND I BOTH FEEL THE OMEGA WAS NOT AT FAULT DUE TO NORMAL OPERATION BOTH BEFORE AND AFTER THIS INCIDENT. THERE WAS A NOTAM FOR POLAR PATH DISTURBANCES AND WE FEEL THIS MAY HAVE AFFECTED THE UNIT. ELIZABETH CITY BEING OFF THE AIR WAS CERTAINLY A CONTRIBUTING FACTOR, IN FACT, FOR THIS TYPE OF FLYING I FEEL IT IS INAPPROPRIATE TO HAVE BEEN CLRED ON AN AIRWAY THAT IS SOLELY PREDICATED ON AN OUT OF SERVICE VOR (OMEGA IS NOT NORMALLY USED FOR NAVIGATION OVER LAND).

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.