Air carrier Captain reported receiving a GPWS 'Obstacle Obstacle; Pull Up' warning and later a 'Terrain Terrain; Pull Up Terrain ' alert while on the ILS approach to EINN/SNN. Crew determined warnings to be erroneous and landed normally.

Narrative

Event: EGPWS Mode 6 & Mode 2 Alerts on Final ApproachLocation: Shannon Airport (SNN)Phase of Flight: Final Approach (ILS)Conditions: Daylight VMCAircraft Type: Aircraft XNavigation Status: GPS PRIMARY available; NAV ACCURACY HIGHWhile descending through approximately 1800 feet AGL on a stabilized ILS approach to Runway 06 at SNN with Autopilot engaged and all parameters within limits; the EGPWS generated a Mode 6 warning:OBSTACLE; OBSTACLE; PULL UP"The crew was operating in daylight visual meteorological conditions; and it was immediately evident that there was no actual obstacle threat. Visual confirmation of terrain and obstacle clearance was positive. The highest known obstacle in the vicinity is approximately 10 NM north of the event location.Cross-checked navigation data confirmed the aircraft was:Properly established on both the localizer and glide slope. Within published lateral and vertical tolerances. With GPS PRIMARY available and NAV ACCURACY: HIGH As the airfield was clearly in view; and all visual and instrument references were stable and nominal; the crew assessed the warning as false and continued the approach without deviation.At approximately 200 feet AGL; a second EGPWS alert occurred:"TERRAIN; TERRAIN"Followed shortly by:"TERRAIN; TERRAIN; PULL UP"Again; the aircraft was in a stable descent on the glide slope; with continuous visual contact with the runway environment. Instrument references remained nominal; and there was no indication of actual terrain conflict. The alert was assessed by the crew as spurious; likely related to either:A false terrain prediction in the EGPWS databaseA possible position error due to a recent GPS interferenceRadar altimeter intermittent malfunction (post-flight anecdotal information of another event at FL 350 within the past 4 weeks)A Stable flight path was maintained in both cases; as situational awareness and all available cues confirmed safe operationThe events were logged in the aircraft logbookThe false EGPWS alerts were reportedRecommendations: Consider reviewing the obstacle and terrain database validity for the area surrounding Shannon AirportShare this event for EGPWS system performance monitoring and database refinement Include this scenario in crew training or briefings Investigating specific root causes with regard to possible hardware failures"