Flight Crew Last 90 Days 150; Flight Crew Total 8500; Flight Crew Type 500
Inflight Event / Encounter Wake Vortex Encounter
General None Reported / Taken
Environment - Non Weather Related
Joining the localizer at ORD we encountered wake turbulence from a B747 ahead of us. The turbulence was surprising because it put our aircraft into a bank one direction; we recovered; then the other (probably the other wake trail.) Very little altitude was gained or lost. We felt this was probably pretty surprising to the passengers as it had been a very smooth ride up to that point. The Captain decided to make an announcement explaining this to the passengers. The heavy was more than 5 miles ahead of us but we didn't have it in sight. Must have been some strange wind patterns or the heavy was high joining or something for us to encounter this because we were pretty much on the localizer and glideslope joining. The rest of the approach we came in a half dot high and didn't encounter anymore of the wake.
B737 First Officer reported encountering wake vortex in trail of a B747 on approach at ORD that caused uncommanded roll.