B737 pilot reported encountering wake turbulence on approach to jfk in trail of a B747.

Attributes
ACN	1465932
Time
Date	201704
Place
Locale Reference	JFK.Airport
State Reference	NY
Aircraft 1
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Flight Plan	IFR
Aircraft 2
Make Model Name	B747 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Final Approach
Flight Plan	IFR
Person 1
Function	Other / Unknown
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Deviation - Altitude Excursion From Assigned Altitude Inflight Event / Encounter Wake Vortex Encounter

Narrative:

During ILS runway 31R approach at jfk airport; 3000 ft; level and localizer captured; glideslope armed; we were authorized by ATC to land on 31R as fourth [in line behind a] B747 which was five miles [in front of] us. [ATC] also requested 170 kts until zulab; therefore we set flaps 10 and speed was reduced to keep 5 and 7 miles [in trail] due to wake turbulence.approximately 2 miles before malde; suddenly the roll angle [increased to] 35 degrees caused by wake turbulence. Autopilot was disengaged and 'bank angle' was [heard] then we lost 200 ft. Recovery maneuver was performed; and the localizer was recovered; [about] 2 miles [from] zulab. We told ATC about the event. [They told] us that we could continue with the approach.

Original NASA ASRS Text

Title: B737 pilot reported encountering wake turbulence on approach to JFK in trail of a B747.

Narrative: During ILS Runway 31R approach at JFK airport; 3000 ft; level and localizer captured; glideslope armed; we were authorized by ATC to land on 31R as fourth [in line behind a] B747 which was five miles [in front of] us. [ATC] also requested 170 kts until ZULAB; therefore we set flaps 10 and speed was reduced to keep 5 and 7 miles [in trail] due to wake turbulence.Approximately 2 miles before MALDE; suddenly the roll angle [increased to] 35 degrees caused by wake turbulence. Autopilot was disengaged and 'Bank Angle' was [heard] then we lost 200 ft. Recovery maneuver was performed; and the localizer was recovered; [about] 2 miles [from] ZULAB. We told ATC about the event. [They told] us that we could continue with 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.