An aircraft on the lga runway 31 localizer received a 'caution terrain' alert near 600 ft while thre...

Narrative:

We were on the localizer 31 approach into lga when approaching the MDA of 600 ft we received a 'caution terrain' alert. The descent rate was 1;000 ft per minute and we had broken out about 3-4 miles from the runway when we received the alert; 2 to 3 flashes of the taws light. I had visual contact with the buildings ahead so we continued the approach. ATC also gave us a terrain alert right after we received the alert from the aircraft. The controller also gave alerts to the aircraft immediately in front and behind us on the approach. We followed the localizer 31 approach as depicted on the approach plate; the approach isn't overly difficult; only one altitude change from 1;700 to the 600 ft MDA. I don't know if this a local issue or weather induced. The altimeter setting for the approach was 29.50; roughly 2-3 hours later the altimeter had risen to 29.93; a dramatic rise. 30 minutes after the approach the altimeter in the aircraft read slightly below zero with the 29.50 setting used during the approach. I'd like to know if this is going to be a reoccurring issue using the localizer 31 approach or a singular event.

Original NASA ASRS Text

Title: An aircraft on the LGA Runway 31 LOC received a 'CAUTION TERRAIN' alert near 600 FT while three to four miles from the runway in visual conditions. The aircraft ahead; behind and the reporter all received ATC low altitude alerts.

Narrative: We were on the LOC 31 approach into LGA when approaching the MDA of 600 FT we received a 'caution terrain' alert. The descent rate was 1;000 FT per minute and we had broken out about 3-4 miles from the runway when we received the alert; 2 to 3 flashes of the TAWS light. I had visual contact with the buildings ahead so we continued the approach. ATC also gave us a terrain alert right after we received the alert from the aircraft. The Controller also gave alerts to the aircraft immediately in front and behind us on the approach. We followed the LOC 31 approach as depicted on the approach plate; the approach isn't overly difficult; only one altitude change from 1;700 to the 600 FT MDA. I don't know if this a local issue or weather induced. The altimeter setting for the approach was 29.50; roughly 2-3 hours later the altimeter had risen to 29.93; a dramatic rise. 30 minutes after the approach the altimeter in the aircraft read slightly below zero with the 29.50 setting used during the approach. I'd like to know if this is going to be a reoccurring issue using the LOC 31 approach or a singular 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	936943
Time
Date	201103
Local Time Of Day	0601-1200
Place
Locale Reference	LGA.Airport
State Reference	NY
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Make Model Name	Light Transport Low Wing 2 Turboprop Eng
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Flight Plan	IFR
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 11 Flight Crew Total 3700 Flight Crew Type 2250
Events
Anomaly	Inflight Event / Encounter CFTT / CFIT

An aircraft on the lga runway 31 localizer received a 'caution terrain' alert near 600 ft while three to four miles from the runway in visual conditions. The aircraft ahead; behind and the reporter all received ATC low altitude alerts.