B737 Next Generation Undifferentiated
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Flight Crew Last 90 Days 182; Flight Crew Total 6628; Flight Crew Type 2628
Situational Awareness
Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Unstabilized Approach; Inflight Event / Encounter Wake Vortex Encounter
General None Reported / Taken
Procedure; Human Factors; Environment - Non Weather Related
Ceilings were sufficient for CAT I approach; but very close to minimums. On final; Approach and Tower issued wake turbulence advisory for heavy Airbus in front of us (6-7 miles) per TCAS. As First Officer Pilot Flying approach was stable (autopilot engaged). Approach light system was acquired just above minimums; and then runway/markings/lighting was acquired prior to 100 feet per FOM. I stated 'Continue' instead of 'landing' due to lights vs runway contrary to the FOM; creating a challenge from PM (CA) to confirm my intentions. Past the threshold (below 50 feet); the aircraft began to roll and was pushed slightly left of centerline due to wake turbulence. I rolled the aircraft back and attempted to correct back to centerline. I accepted a landing slightly left of centerline and the landing rollout was uneventful. After landing; ACARS data reflected a 5.0 degree bank on landing (maximum 7.5). In hindsight; a go-around would have been a better choice.
We were cautioned following heavy on ILS 8L. We saw we were 5 miles in trail. Per FOM since it was First Officer's leg we briefed the ILS CAT1 approach and back up CAT3. When we left [departure airport]; forecast was well above CAT 1. RVR was 2;000; so we briefed that just prior to FAF get final RVR and if need be switch to CAT 3 change mins from CAT 1 barometric to CAT 3 radio alt mins and Captain take control. Second auto pilot was turned on when approach clearance given.At about 50 feet; I observed the nose come up slightly and I thought First Officer was starting flare early although very small up nose. Then at about 30 feet; we got a roll input which the First Officer countered and we rolled in opposite direction and drifted well left of center line. As I was about to call go around; the First Officer stabilized the situation and we landed left of centerline. It was by no means a hard landing in vertical drop and roll was stable. However much to my surprise when we checked post report on roll it showed 5 degrees with wingtip contact at 7.5. I would never thought it was that close to wing contact.Post shut down debrief reveal the first error on my part was engaging second autopilot when a First Officer non autoland was planned. Looking up in FM second autopilot can be turned on NLT 800 feet. This should have been delayed until decision to change to CAT if needed prior to FAF. This caused aircraft to trim nose up and it was that nose up trim the First Officer was fighting when he turned autopilot off. Second now that I have a better 'picture' of what excessive roll looks like a go-around should have been called.I can say though had RVR dropped and it was an autoland the first rolling movement would definitely command a go-around as an auto and would not have been successful.
B737NG flight crew reported continuing to landing after an uncommanded nose up and roll was observed on short final.