A319
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 195; Flight Crew Type 1211
Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Wake Vortex Encounter; Inflight Event / Encounter Weather / Turbulence
General Maintenance Action
Weather; Environment - Non Weather Related
On ILS PRM (Precision Runway Monitor) approach ORD 10C (autopilot and autothrust required); assigned 170 KIAS to FAF (Final Approach Fix). I called 'Flaps 3' below 175 KIAS to maintain 170. Just prior to the FAF; the aircraft encountered either wake turbulence from the proceeding aircraft or some other form of unstable air. The airspeed quickly rose above the Flaps 3 limit of the aircraft. During our debrief; the Captain and I thought it was about 10 knots above the limit for 2 to 3 seconds. I called for the landing gear to help manage the speed. Airspeed returned to normal; we continued to configure for landing; and landed uneventfully. The Captain contacted Maintenance to write up the overspeed. Maintenance did the inspection and reported to us the overspeed was within limits.
A319 First Officer reported a flap overspeed occurred on approach into ORD when they encountered either wake turbulence or unstable air.