Prior to an overwater flight, an air carrier flight crew failed to select align on the two inertial navigation system during preflight procedures. While running the start checklist, the captain noticed that align had not been selected, and decided to go with only an omega. After departure the omega became unreliable and the flight over the caribbean and the gulf of mexico was made by the use of VOR, and ADF. The first officer reports that he believes that the flight crew deviated from the flight planned route.

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Attributes
ACN	333148
Time
Date	199604
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : pty
State Reference	FO
Altitude	msl bound lower : 33000 msl bound upper : 33000
Aircraft 1
Controlling Facilities	artcc : mhtg
Operator	common carrier : air carrier
Make Model Name	DC-10 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other ground : preflight
Route In Use	enroute : other oceanic enroute other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : flight engineer pilot : atp pilot : commercial
Experience	flight time last 90 days : 180 flight time total : 9000 flight time type : 2000
ASRS Report	333148
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : critical non adherence : published procedure non adherence : far non adherence : clearance other anomaly other other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted none taken : unable
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While doing the preflight, the INS and omega were loaded with the waypoint. We did not go to align with the INS's. On start check, the captain noticed that the INS's were not aligned and he decided to position the INS's mode selections to altitude reference. Captain said we are going with one omega. En route to fargo, nd, approximately 160 mi out of panama city, panama, the omega became unreliable for navigation. The captain had made position reports using the unreliable omega, vors, and ADF's across the caribbean and gulf of mexico. From there we flew vors and radar vectors to fargo, nd. I believe that we were off course on our flight planned route in the caribbean and the gulf of mexico. Where and when and by how much, I do not know.

Original NASA ASRS Text

Title: PRIOR TO AN OVERWATER FLT, AN ACR FLC FAILED TO SELECT ALIGN ON THE TWO INERTIAL NAV SYS DURING PREFLT PROCS. WHILE RUNNING THE START CHKLIST, THE CAPT NOTICED THAT ALIGN HAD NOT BEEN SELECTED, AND DECIDED TO GO WITH ONLY AN OMEGA. AFTER DEP THE OMEGA BECAME UNRELIABLE AND THE FLT OVER THE CARIBBEAN AND THE GULF OF MEXICO WAS MADE BY THE USE OF VOR, AND ADF. THE FO RPTS THAT HE BELIEVES THAT THE FLC DEVIATED FROM THE FLT PLANNED RTE.

Narrative: WHILE DOING THE PREFLT, THE INS AND OMEGA WERE LOADED WITH THE WAYPOINT. WE DID NOT GO TO ALIGN WITH THE INS'S. ON START CHK, THE CAPT NOTICED THAT THE INS'S WERE NOT ALIGNED AND HE DECIDED TO POS THE INS'S MODE SELECTIONS TO ALT REF. CAPT SAID WE ARE GOING WITH ONE OMEGA. ENRTE TO FARGO, ND, APPROX 160 MI OUT OF PANAMA CITY, PANAMA, THE OMEGA BECAME UNRELIABLE FOR NAV. THE CAPT HAD MADE POS RPTS USING THE UNRELIABLE OMEGA, VORS, AND ADF'S ACROSS THE CARIBBEAN AND GULF OF MEXICO. FROM THERE WE FLEW VORS AND RADAR VECTORS TO FARGO, ND. I BELIEVE THAT WE WERE OFF COURSE ON OUR FLT PLANNED RTE IN THE CARIBBEAN AND THE GULF OF MEXICO. WHERE AND WHEN AND BY HOW MUCH, I DO NOT KNOW.

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.