Air carrier captain reported false reading from the ILS on final approach to lga airport.

Attributes
ACN	1704490
Time
Date	201911
Local Time Of Day	1801-2400
Place
Locale Reference	LGA.Airport
State Reference	NY
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Flight Plan	IFR
Person 1
Function	Pilot Not Flying Captain
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Less Severe Inflight Event / Encounter CFTT / CFIT

Narrative:

Visual to 22. Backed up by ILS. On the final vector to join the autopilot intercepted a false localizer and glideslope and started following it down. ATC issued low altitude alert and I (pm; pilot monitoring) kicked off the autopilot and told the first officer (first officer) to stop the descent. Continued the approach visually to a normal landing.

Original NASA ASRS Text

Title: Air Carrier Captain reported false reading from the ILS on final approach to LGA airport.

Narrative: Visual to 22. Backed up by ILS. On the final vector to join the autopilot intercepted a false localizer and glideslope and started following it down. ATC issued low altitude alert and I (PM; Pilot Monitoring) kicked off the autopilot and told the FO (First Officer) to stop the descent. Continued the approach visually to a normal landing.

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.