An apparent IRU driven map shift contributed to a B757-200 flight crew's misidentification of the wr...

Attributes
ACN	870481
Time
Date	201001
Local Time Of Day	1801-2400
Place
Locale Reference	MSY.Airport
State Reference	LA
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Flight Plan	IFR
Component
Aircraft Component	INS / IRS / IRU
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 100 Flight Crew Total 14500 Flight Crew Type 3750
Person 2
Function	First Officer Pilot Not Flying
Experience	Flight Crew Last 90 Days 90 Flight Crew Total 5000 Flight Crew Type 2200
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Clearance Deviation - Track / Heading All Types

Narrative:

Map shift encounter: approximately 15 NM north of msy; approach control asked if we had the airport in sight. We called what we thought was the field and it also agreed in the general area in relation to the HSI map display. As we proceeded inbound to where we believed was the msy airport; tower informed us that we were paralleling the final approach path well right of course and redirected our attention to our 10 o'clock position where msy truly was. Runway 19 at msy was approximately 3.5-4.0 NM left of our position. We maneuvered the aircraft to line up with our intended runway for landing. Then on short final we received a GPWS warning. The FMC's clearly were not in agreement with the actual aircraft position. Landing uneventful. Contributing factors may have been that the localizer to runway 19 was NOTAM'd inop; but we still tuned it in for any info it might provide. Also losing sight of the airport due to the sun glare and haze contributed.

Original NASA ASRS Text

Title: An apparent IRU driven map shift contributed to a B757-200 flight crew's misidentification of the wrong airport when cleared for a visual approach to MSY.

Narrative: Map Shift Encounter: Approximately 15 NM North of MSY; Approach Control asked if we had the airport in sight. We called what we thought was the field and it also agreed in the general area in relation to the HSI map display. As we proceeded inbound to where we believed was the MSY airport; Tower informed us that we were paralleling the final approach path well right of course and redirected our attention to our 10 o'clock position where MSY truly was. Runway 19 at MSY was approximately 3.5-4.0 NM left of our position. We maneuvered the aircraft to line up with our intended runway for landing. Then on short final we received a GPWS warning. The FMC's clearly were not in agreement with the actual aircraft position. Landing uneventful. Contributing factors may have been that the localizer to Runway 19 was NOTAM'D inop; but we still tuned it in for any info it might provide. Also losing sight of the airport due to the sun glare and haze contributed.

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.

An apparent IRU driven map shift contributed to a B757-200 flight crew's misidentification of the wrong airport when cleared for a visual approach to msy.