B737-800 flight crew reported descending below charted altitude of 1;700 ft on approach to lga after...

Attributes
ACN	1273981
Time
Date	201506
Local Time Of Day	0601-1200
Place
Locale Reference	LGA.Airport
State Reference	NY
Environment
Light	Daylight
Aircraft 1
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Route In Use	Vectors
Flight Plan	IFR
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Commercial
Person 2
Function	Pilot Not Flying First Officer
Events
Anomaly	Deviation - Altitude Excursion From Assigned Altitude Inflight Event / Encounter CFTT / CFIT

Narrative:

I was the ca and PF. We were on vectors and assigned altitudes with clearance to descend to fly the RNAV Y to runway 4. I used vertical speed to initiate descent. We got low prior to dnnis and received a call from lga ATC. We corrected to 1700 feet; VNAV path; and flew the remainder of the RNAV Y approach to runway 4 for an uneventful full stop landing.slow down sooner and; on a divert relocation flight; brief the whole approach prior to takeoff.

Original NASA ASRS Text

Title: B737-800 flight crew reported descending below charted altitude of 1;700 FT on approach to LGA after a short flight.

Narrative: I was the CA and PF. We were on vectors and assigned altitudes with clearance to descend to fly the RNAV Y to Runway 4. I used vertical speed to initiate descent. We got low prior to DNNIS and received a call from LGA ATC. We corrected to 1700 feet; VNAV PATH; and flew the remainder of the RNAV Y approach to Runway 4 for an uneventful full stop landing.Slow down sooner and; on a divert relocation flight; brief the whole approach prior to takeoff.

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.

B737-800 flight crew reported descending below charted altitude of 1;700 ft on approach to lga after a short flight.