Track deviation on oceanic flight account malfunctioning omega navigation systems.

Attributes
ACN	88867
Time
Date	198806
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : oak
State Reference	CA
Altitude	msl bound lower : 36000 msl bound upper : 38000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zhn artcc : zoa
Operator	common carrier : air carrier
Make Model Name	Heavy Transport, Low Wing, 4 Turbojet Eng
Flight Phase	cruise other
Route In Use	enroute : other oceanic enroute : pacific
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 170 flight time total : 20800 flight time type : 1850
ASRS Report	88867
Person 2
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	other spatial deviation
Independent Detector	atc equipment other atc equipment : unspecified
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Plan filed and flight cleared hnl MKK2 cluts R465 clukk oak J84 MVA J56 slc slc. Airborne hnk XA44Z. Abeam molokai cleared direct clutz. Both omegas showed gradual deviation to right. Accepted vector to cluts. From hnl center while updating present position with VOR/DME fix from molokai VORTAC. Both omegas were updated. After cluts and enroute on R465 both omegas showed incorrect deviation indications and incorrect heading inputs to the computers appeared to be the cause. Navigation was continued to clukk on R465 and position 10 miles south of route and 1 1/2 mins ahead of ETA clukk confirmed by oak VORTAC at xd 527. During flight #2 omega computer was replaced with an onboard spare. On test it showed code representing incorrect heading input.

Original NASA ASRS Text

Title: TRACK DEVIATION ON OCEANIC FLT ACCOUNT MALFUNCTIONING OMEGA NAVIGATION SYSTEMS.

Narrative: PLAN FILED AND FLT CLRED HNL MKK2 CLUTS R465 CLUKK OAK J84 MVA J56 SLC SLC. AIRBORNE HNK XA44Z. ABEAM MOLOKAI CLRED DIRECT CLUTZ. BOTH OMEGAS SHOWED GRADUAL DEVIATION TO RIGHT. ACCEPTED VECTOR TO CLUTS. FROM HNL CENTER WHILE UPDATING PRESENT POSITION WITH VOR/DME FIX FROM MOLOKAI VORTAC. BOTH OMEGAS WERE UPDATED. AFTER CLUTS AND ENROUTE ON R465 BOTH OMEGAS SHOWED INCORRECT DEVIATION INDICATIONS AND INCORRECT HEADING INPUTS TO THE COMPUTERS APPEARED TO BE THE CAUSE. NAVIGATION WAS CONTINUED TO CLUKK ON R465 AND POSITION 10 MILES SOUTH OF ROUTE AND 1 1/2 MINS AHEAD OF ETA CLUKK CONFIRMED BY OAK VORTAC AT XD 527. DURING FLT #2 OMEGA COMPUTER WAS REPLACED WITH AN ONBOARD SPARE. ON TEST IT SHOWED CODE REPRESENTING INCORRECT HEADING INPUT.

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.