A MD80's FMS reverted to the dead reckoning mode on final but the crew missed the dr cue in the pfd ...

Attributes
ACN	861528
Time
Date	200911
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Flight Plan	IFR
Component
Aircraft Component	Navigational Equipment and Processing
Person 1
Function	Captain Pilot Not Flying
Person 2
Function	Pilot Flying First Officer
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Clearance Deviation - Track / Heading All Types

Narrative:

Occurred on approach. Weather was cavu. Approximately 50 miles from the field approach cleared us direct FAF; ILS runway 22. Magenta line showed direct and we proceeded to the fix in navigation. At some point dr(dead reckoning) appeared in the pfd(primary flight display); but it appeared visually that we were on the proper course; so we continued in navigation. Unbeknownst to us the map display was depicting the FAF and runway 22 to be 10 to 15 miles further west than it actually was. Consequently we were both focused on trying to visually acquire the field to the west of its actual location. As we flew through the final approach course. ATC asked us to report the field at 9 o'clock. At that point we asked for vectors to the final approach course; as we still hadn't acquired the field visually. We eventually lined up on runway 22 and landed.

Original NASA ASRS Text

Title: A MD80's FMS reverted to the Dead Reckoning mode on final but the crew missed the DR cue in the PFD and could not see the airport on a night visual approach.

Narrative: Occurred on approach. Weather was CAVU. Approximately 50 miles from the field approach cleared us direct FAF; ILS Runway 22. Magenta line showed direct and we proceeded to the fix in NAV. At some point DR(Dead Reckoning) appeared in the PFD(Primary Flight Display); but it appeared visually that we were on the proper course; so we continued in NAV. Unbeknownst to us the map display was depicting the FAF and Runway 22 to be 10 to 15 miles further west than it actually was. Consequently we were both focused on trying to visually acquire the field to the west of its actual location. As we flew through the final approach course. ATC asked us to report the field at 9 o'clock. At that point we asked for vectors to the final approach course; as we still hadn't acquired the field visually. We eventually lined up on Runway 22 and landed.

Data retrieved from NASA's ASRS site as of April 2012 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.

A MD80's FMS reverted to the dead reckoning mode on final but the crew missed the dr cue in the pfd and could not see the airport on a night visual approach.