Narrative:

Going into lga we were told to expect the RNAV GPS approach for runway 13. After briefing and setting up for the approach we were given a 030 heading after the lga VOR and then another vector to join the final before the chnzo fix. ATC broadcasted that the visibility had dropped to 1.5 miles at about the same time we were joining the final. We were discussing the minimums when we were cleared for the approach. I mistakenly started my descent at the chnzo fix instead of the rabby fix to 1300 feet. The first officer was putting the gear down and getting us configured so he was busy with the checklist while I descended. By the time I caught my error we were at the meatz fix which allowed a crossing at 1300 feet so I continued the approach with no further problems. I discovered that I had descended about 2 miles early. The main threat that distracted me was the broadcasting of the deteriorating visibility while we were joining final along with task saturation of getting configured for the approach. Slow down and if you get behind just go around and set back up for the approach.

Google
 

Original NASA ASRS Text

Title: CRJ-700 flight crew reported receiving a low altitude alert from ATC after descending early on approach to LGA.

Narrative: Going into LGA we were told to expect the RNAV GPS approach for runway 13. After briefing and setting up for the approach we were given a 030 heading after the LGA VOR and then another vector to join the final before the CHNZO fix. ATC broadcasted that the visibility had dropped to 1.5 miles at about the same time we were joining the final. We were discussing the minimums when we were cleared for the approach. I mistakenly started my descent at the CHNZO fix instead of the RABBY fix to 1300 feet. The FO was putting the gear down and getting us configured so he was busy with the checklist while I descended. By the time I caught my error we were at the MEATZ fix which allowed a crossing at 1300 feet so I continued the approach with no further problems. I discovered that I had descended about 2 miles early. The main threat that distracted me was the broadcasting of the deteriorating visibility while we were joining final along with task saturation of getting configured for the approach. Slow down and if you get behind just go around and set back up for the approach.

Data retrieved from NASA's ASRS site 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.