EMB ERJ 190/195 ER/LR
Flight Crew Air Transport Pilot (ATP)
Confusion; Workload
Aircraft Equipment Problem Less Severe; Inflight Event / Encounter Unstabilized Approach
Flight Crew Became Reoriented; Flight Crew Overcame Equipment Problem
ATC Equipment / Nav Facility / Buildings; Aircraft; Environment - Non Weather Related
We were on the base to final for ILS Runway 22 at LGA; ATC gave us clearance to turn on heading 250; descend to 2;000 feet and cleared for ILS Approach Runway 22; I turned on heading; descended to 2;000 feet in FLCH and armed approach ( LOC;GS were armed). Localizer moved and was captured on FMA around 7-8 DME and GS was alive; when LOC needle was less than 1 dot; the airplane suddenly roll wings level with increasing descent. The distance to the runway was around 6-7 miles. I checked FMA; it was in ROLL and Flight Path Angle (FPA) mode. I disconnected autopilot making correction to bring back the airplane on the correct flight path.I distrust the automation at this time and continued approach in the manual mode; monitoring raw data indication and VASI on the Runway 22. During the maneuver; I went slightly lower on the glide path and received twice EGPWS glideslope alert. I corrected glide path and landed uneventfully.My First Officer told me after landing that he experienced and observed 3 cases of these anomalies over the last several months and it was ILS approach Runway 22 and distance when anomalies occurred from 6 to 10 miles on final. I suggested him to submit a report about the anomalies too. I did not find any NOTAMs regarding these anomalies and ATC did not notify us about deviation.I could only suspect false LOC and GS or interference with ILS signals. The airplane equipment worked correctly on the next approach. The high workload and task saturation to correct the flight path after anomalies distracted me from monitoring the glide path.
EMB190 Captain experiences an autopilot anomaly during LOC and glide path capture of the ILS 22 at LGA. The autopilot initially seemed to capture the LOC then rolled wings level with increasing descent below the glide path and displaying ROLL and Flight Path Angle (FPA) in the FMA. The autopilot is disconnected and the approach continued manually. The First Officer informs the Captain that he has seen this anomaly occur several times during the ILS 22 to LGA over the last few months.