EMB ERJ 170/175 ER/LR
Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Distraction
Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Unstabilized Approach; Inflight Event / Encounter Wake Vortex Encounter; Inflight Event / Encounter Weather / Turbulence
Flight Crew Became Reoriented
Environment - Non Weather Related; Weather; Human Factors
On short final to runway 28C into ORD we were mis-configured for landing.  We ran a landing checklist to the line; and got distracted due to gusty wind conditions; a short visual final approach; and also following a heavy 777; which was giving us wake turbulence.  Therefore we forgot to run the checklist below the line therefore not configuring the aircraft with flaps 5.  We noticed the mistake right as we got a message of 'too low flaps'.  This message sounded right as I was moving the flap lever to the 5 position.This event could have been prevented by not getting distracted with the gusty wind conditions and also the wake turbulence that was encountered.  Better CRM could have been used by cross checking the aircraft configuration prior to landing and also finishing the landing checklist below the line.
While on approach to landing on Runway 28C at ORD. We were kept somewhat fast and vectored close in behind another aircraft which was a heavy Airbus. Encountering moderate turbulence due to the gusty surface conditions; concerned about the distance that we were behind the heavy traffic; and becoming distracted with ATC. We forgot to go to Flaps 5 until around 700 AGL. After noticing are mistake we selected Flaps 5 and landed.Put flying the aircraft and doing of checklist first. And then contend with ATC. Also; we should have done a go around when we learned we did not have the proper flap setting below 1;000 feet.
ERJ-175 First Officer reported failing to complete the Landing Checklist and they were late selecting landing flaps. Gusty winds and wake turbulence were contributing factors.