Erroneous coordinates set in INS computers. Aircraft landed at point of origin.

Attributes
ACN	303203
Time
Date	199504
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : rjtg airport : rjff
State Reference	FO
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	DC-10 30
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	climbout : intermediate altitude ground : preflight other
Route In Use	enroute : other oceanic enroute : pacific enroute airway : rjtg
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : commercial pilot : cfi pilot : atp pilot : instrument
Experience	flight time last 90 days : 230 flight time total : 28000 flight time type : 9000
ASRS Report	303203
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Aircraft departed fukuoka, japan, en route to guam. Shortly after takeoff a difference between the INS distance and the DME distance from the fukuoka VOR (dgc) was noted. Due to WX conditions which required several deviations from course during climb out and initial cruise, we were unable to fly over a known fix such as a VOR, etc, to verify the accuracy of our INS. However, by using other means of checking (using the remote function of the INS) it was determined that all 3 INS units were not giving the proper navigation information. We therefore returned to fukuoka to determine cause. In my opinion, the probable cause of the INS error was due to improper insertion first officer the ramp coordinates in fuk. Although all 3 INS units were checked and verified by both the captain and first officer, there is a strong suspicion among this crew that N3355.8 was inserted and verified by both myself and the first officer together instead of the correct coordinates of N3335.8. With proper coordinates inserted the flight returned to guam with all INS units operating normally.

Original NASA ASRS Text

Title: ERRONEOUS COORDINATES SET IN INS COMPUTERS. ACFT LANDED AT POINT OF ORIGIN.

Narrative: ACFT DEPARTED FUKUOKA, JAPAN, ENRTE TO GUAM. SHORTLY AFTER TKOF A DIFFERENCE BTWN THE INS DISTANCE AND THE DME DISTANCE FROM THE FUKUOKA VOR (DGC) WAS NOTED. DUE TO WX CONDITIONS WHICH REQUIRED SEVERAL DEVS FROM COURSE DURING CLBOUT AND INITIAL CRUISE, WE WERE UNABLE TO FLY OVER A KNOWN FIX SUCH AS A VOR, ETC, TO VERIFY THE ACCURACY OF OUR INS. HOWEVER, BY USING OTHER MEANS OF CHKING (USING THE REMOTE FUNCTION OF THE INS) IT WAS DETERMINED THAT ALL 3 INS UNITS WERE NOT GIVING THE PROPER NAV INFO. WE THEREFORE RETURNED TO FUKUOKA TO DETERMINE CAUSE. IN MY OPINION, THE PROBABLE CAUSE OF THE INS ERROR WAS DUE TO IMPROPER INSERTION FO THE RAMP COORDINATES IN FUK. ALTHOUGH ALL 3 INS UNITS WERE CHKED AND VERIFIED BY BOTH THE CAPT AND FO, THERE IS A STRONG SUSPICION AMONG THIS CREW THAT N3355.8 WAS INSERTED AND VERIFIED BY BOTH MYSELF AND THE FO TOGETHER INSTEAD OF THE CORRECT COORDINATES OF N3335.8. WITH PROPER COORDINATES INSERTED THE FLT RETURNED TO GUAM WITH ALL INS UNITS OPERATING NORMALLY.

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.