Czqx advises DC10 of slight navigation tracking error.

Attributes
ACN	522713
Time
Date	200108
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : czqx.artcc
State Reference	FO
Altitude	msl single value : 32000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : czqx.artcc
Operator	common carrier : air carrier
Make Model Name	DC-10 30
Operating Under FAR Part	Part 121
Flight Phase	cruise : level ground : takeoff roll
Route In Use	enroute airway : natd.airway
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 110 flight time total : 14500 flight time type : 100
ASRS Report	522713
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	non adherence : published procedure non adherence : clearance other spatial deviation
Independent Detector	atc equipment other atc equipment : nav computers other controllera
Resolutory Action	controller : issued alert flight crew : returned to intended or assigned course flight crew : overcame equipment problem flight crew : overrode automation
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

The flight from amsterdam to miami was in normal cruise to navigation point oystr. When the aircraft reached oystr, gander radar reported to the pilots that the aircraft was 6 mi to the right of point oystr. The pilots had not been able to update the litton navigation computers for about 3 1/2 hours. All computers and pilot navigation waypoint plots and accuracy checks had shown the aircraft to be on course. All xtk's had been 0.1 or less and xte's 0.2 or less after each waypoint. There were no conflicts with other aircraft. Once over canada, the crew was able to update the navigation computers. The update showed the aircraft to be about 6 mi off course correcting the aircraft back to course, direct to navigation point topps. Upon landing in miami, the accuracy of the computers were checked as part of the company procedures. 2 computers showed 13.2 mi of error and the remaining computer showed 7.8 mi track error. The results were reported in the aircraft logbook. All company procedures were followed and the aircraft landed in miami without further incident.

Original NASA ASRS Text

Title: CZQX ADVISES DC10 OF SLIGHT NAV TRACKING ERROR.

Narrative: THE FLT FROM AMSTERDAM TO MIAMI WAS IN NORMAL CRUISE TO NAV POINT OYSTR. WHEN THE ACFT REACHED OYSTR, GANDER RADAR RPTED TO THE PLTS THAT THE ACFT WAS 6 MI TO THE R OF POINT OYSTR. THE PLTS HAD NOT BEEN ABLE TO UPDATE THE LITTON NAV COMPUTERS FOR ABOUT 3 1/2 HRS. ALL COMPUTERS AND PLT NAV WAYPOINT PLOTS AND ACCURACY CHKS HAD SHOWN THE ACFT TO BE ON COURSE. ALL XTK'S HAD BEEN 0.1 OR LESS AND XTE'S 0.2 OR LESS AFTER EACH WAYPOINT. THERE WERE NO CONFLICTS WITH OTHER ACFT. ONCE OVER CANADA, THE CREW WAS ABLE TO UPDATE THE NAV COMPUTERS. THE UPDATE SHOWED THE ACFT TO BE ABOUT 6 MI OFF COURSE CORRECTING THE ACFT BACK TO COURSE, DIRECT TO NAV POINT TOPPS. UPON LNDG IN MIAMI, THE ACCURACY OF THE COMPUTERS WERE CHKED AS PART OF THE COMPANY PROCS. 2 COMPUTERS SHOWED 13.2 MI OF ERROR AND THE REMAINING COMPUTER SHOWED 7.8 MI TRACK ERROR. THE RESULTS WERE RPTED IN THE ACFT LOGBOOK. ALL COMPANY PROCS WERE FOLLOWED AND THE ACFT LANDED IN MIAMI WITHOUT FURTHER INCIDENT.

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.