An air carrier flight crew inbound to einn received incorrect altimeter settings from ATC and descen...

Narrative:

[We were] on approach to einn; cleared from FL80 to 3;000; altimeter 1030 (hpa). I read back the clearance and altimeter setting. We had the previous ATIS; so I requested the latest ATIS on the FMC. Passing through about 3;200 MSL; the controller queried; 'confirm you are cleared to 3;000 ft; altimeter 1030... I show you at 2;300 ft.' meanwhile; the radar altimeter had just come alive (showing 2;500 ft); so I looked at the GPWS to see that the highest terrain was 1;800 ft; which agreed with the approach plate. I told the controller; 'yes; we are leveling at 3;000 ft; altimeter setting 1030. Confirm the altimeter setting is not actually 1003?' the controller again stated the altimeter setting was 1030. Just then; another voice came over the frequency stating; 'shannon altimeter is 995 hpa!' I responded; we reset our altimeters in the cockpit; and climbed up to 3;000 ft. The mis-set altimeter has caused an altitude deviation of approximately 950 ft. I don't believe we were ever below about 2;000 ft AGL during this event.

Original NASA ASRS Text

Title: An air carrier flight crew inbound to EINN received incorrect altimeter settings from ATC and descended below their cleared altitude as a result. ATC caught the deviation and the altimeter settings were corrected.

Narrative: [We were] on approach to EINN; cleared from FL80 to 3;000; altimeter 1030 (hPa). I read back the clearance and altimeter setting. We had the previous ATIS; so I requested the latest ATIS on the FMC. Passing through about 3;200 MSL; the Controller queried; 'Confirm you are cleared to 3;000 FT; altimeter 1030... I show you at 2;300 FT.' Meanwhile; the radar altimeter had just come alive (showing 2;500 FT); so I looked at the GPWS to see that the highest terrain was 1;800 FT; which agreed with the approach plate. I told the Controller; 'Yes; we are leveling at 3;000 FT; altimeter setting 1030. Confirm the altimeter setting is not actually 1003?' The Controller again stated the altimeter setting was 1030. Just then; another voice came over the frequency stating; 'Shannon altimeter is 995 hPa!' I responded; we reset our altimeters in the cockpit; and climbed up to 3;000 FT. The mis-set altimeter has caused an altitude deviation of approximately 950 FT. I don't believe we were ever below about 2;000 FT AGL during this event.

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.

Attributes
ACN	958751
Time
Date	201107
Place
Locale Reference	EINN.Tower
State Reference	FO
Environment
Light	Daylight
Aircraft 1
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Flight Plan	IFR
Component
Aircraft Component	Altimeter
Person 1
Function	First Officer
Person 2
Function	Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	ATC Issue All Types Deviation - Altitude Overshoot Deviation - Procedural Published Material / Policy Deviation - Procedural Clearance

An air carrier flight crew inbound to einn received incorrect altimeter settings from ATC and descended below their cleared altitude as a result. ATC caught the deviation and the altimeter settings were corrected.