Date: 202012
Local time of day: 1201-1800
Location: ZZZZ.Airport, FO
Flight conditions: IMC
Weather elements / visibility: Rain
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Landing
ATC / advisory: Tower ZZZZ
Aircraft component: Brake System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Human factors: Situational Awareness; Time Pressure; Workload; Training / Qualification
Second reporter function: Pilot Not Flying; Captain
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Other / Unknown; Ground Event / Encounter Weather / Turbulence; Ground Event / Encounter Loss Of Aircraft Control; Ground Excursion Runway
Detector: Person Flight Crew
When detected: Other Landing
Result: Flight Crew Regained Aircraft Control
Contributing factors: Environment - Non Weather Related; Aircraft; Human Factors; Weather
Primary problem: Human Factors

Narrative: ATC said there was rain on the field. There was a B737 flight ahead of us on the approach by 5 to 10 minutes. We were listening to both Approach and Tower to monitor their approach and landing. We discussed holding; prior to the preceding aircraft landing. The preceding B737 reported safe on deck; medium braking; and no issues. They said they broke out 300 feet above minimums; 500 feet above ground. This gave us confidence to conduct the approach and landing. We complied with the wet runway requirements on the 10-7 page (max braking).We were fully configured with flaps 30 by the final approach fix with the landing checklist complete. We were stable at both the 1000 feet and 500 feet calls. Approach was mostly smooth in the clouds with no turbulence. Auto throttles moved very little. The rain was moderate; maybe moderate to high. Once we broke out; we could see the runway the entire time. Wiper were keeping up; but on high. We broke out about 300 feet. Saw some ground before that; so knew we were close to breaking out. Saw the Runway End Identifier Lights at 300 feet and the runway edge lights and center line lights shortly after. Captain called 'approaching minimums' just prior to breaking out and I said I had the field in sight. The auto pilot and auto throttles were disengaged around 200 feet.Landed a little left of center line; but the right main gear was to the right of the center line. Nose was pointed down the runway. Landing was firm to hard. Flare was normal. Raised nose to arrest descent at 30 feet and power was at idle at touchdown. We were both surprised by the firmness of the landing. Nose wheel was set down normally. I thought we might have skipped a little bit; but the Captain did not think so. Maybe we hydro-planed then the tires grabbed. We immediately started sliding left. I don't remember us turning to the left. It seemed we were pointed down the runway but going left. I stepped on the right rudder; but it didn't seem to have an effect. The left main mount went off the pavement on the left side of the runway. It seemed to take a while to get it back on the pavement with full right rudder and full manual braking. With both pilots stepping on full manual brakes; the aircraft did not seem to slowdown. Never felt the brakes grabbing; and with max brakes; we should have felt the brakes grab. I do not know if that Captain was using the nose wheel steering to assist getting it back to the right.Once back on the pavement; we started to veer to the right; but never left the pavement on the right side. Once on the runway; we added full reverse. We put in full left rudder to keep it on the runway. We got the aircraft direction under control; but it was still pulling to the right with full braking and full left rudder. I think the Captain was countering the pull with nose wheel steering. The aircraft was still difficult to slow down.We exited the runway on the high-speed taxiway on the right at a slow speed and came to a stop just off the runway. Tower asked about our position and if we needed assistance. The aircraft instruments; indications and controls were all normal. The only noticed adverse indication was an 'anti-skid inop ' light. The Captain released the brakes and rolled forward a little to check for a blown tire and brake function. All seemed fine so we said we can proceed to the gate. The taxi in was uneventful.On the taxi in we informed Tower that we may have departed the paved surface and there may be Foreign Object and Debris (FOD)on the runway. After shutdown; the Captain got up and checked on the Flight Attendants and passengers. All seemed fine. One Flight Attendant said she was scared while it was occurring; but otherwise no adverse comments. They were obviously a little shaken at the time; but not excessively so. We contacted Company maintenance and wrote up the maintenance items that we knew about. Several of the Flight Attendants were working our deadhead flight back the next morning. Theystill did not seem to have any after effects from the event and were friendly toward us.Maybe the initial left drift was due to the right gear hydro planning while the left gear had full auto-brakes using anti-skid. Once the left gear returned to the pavement; it's ant-skid may have been damaged; causing the veering to the right under full brakes.


Second narrative: Leg 3 of a transitioning First Officer on a 4 day 15 hour IOE (Initial Operating Experience). The First Officer had just flown the previous leg and done well. He shot the ILS Approach and flew a nice approach to a very nice landing. During the 3 hour sit prior to our flight we discussed the upcoming flight including the special airport requirements and 10-7 pages. Reviewed the flight plan NOTAMs and maintenance status of the aircraft. Noted the sequenced flashing lights to our planned arrival runway were out of service.First Officer made a nice takeoff and climb out to cruise and we continued to update the weather forecasts on the flight. Reviewed 10-7 pages decided to use max braking for training and for possibility of a wet runway. Worst weather report we saw was 4000 feet broken; light rain; and winds 240 at 8. Briefed the arrival and RNAV Approaches due to winds. We also briefed the ILS. Approaching top of descent asked Center which runway was in use. The ILS was the approach in use. Pulled up the landing data. Approaching with radar on noticed a cell and heard [an] aircraft ask for deviations. We asked for and received direct ZZZZZ on the arrival. Descending to 12;000 feet were cleared for the arrival and preceding aircraft ask for direct to a fix. There appeared to be cells just south of the approach. Approach informed us there was rain on the field; we discussed possible holding when we heard [another aircraft] cleared for the approach.I tuned VHF 2 to Tower frequency to get a heads up on the preceding aircraft. They were cleared to land and reported to Tower breaking out a few hundred feet above minimums landed and reported braking action medium. Approach cleared us direct to a fix and to report on the localizer cleared for the approach. Slowed toward 180 kts.; flaps 5 auto pilot on LNAV/VNAV; armed the app mode; made 2;500 feet call; reported established and was told to switch to Tower. Called Tower and reported 9 mile final was cleared to land. I believe Tower also said preceding aircraft broke out at 500 feet and braking action medium. Localizer and glideslope engaged set Touchdown Zone Elevation. Approaching the final approach fix gear down flaps 15 rolled speed back then selected flaps 30 and landing checklist.IMC and moderate rain but little to no turbulence or wind shifts. Passing approximately 1;000 to 800 feet saw ground and lights looking down called 1;000 feet then set Missed Approach altitude. Approach was stable and verified at 500 feet. Called approaching minimums slightly early approximately 400 feet to prepare for possibility of a go around. Approximately 300 feet broke out with Runway End Lights; High Intensity Runway Lights and runway center line in sight. First Officer disengaged the auto pilot and auto throttle approximately 150 to 200 feet. Still raining with wind shield wipers on high but could clearly see the runway environment. Short final dipped 1/4 dot low to try and land in the first 1;000 feet. Heard 50 feet just prior to crossing the threshold then 40; 30. At 30 the First Officer began the flare slowing the rate of descent then began reducing power. Everything appeared normal till the last 5 to 10 feet when it felt like the bottom dropped out to a firm to hard landing. Written up as a hard landing.There was no bounce. Power levers at idle and speed brakes deployed. I have used max auto brakes often due to the demo requirement for Operational Experience. Ordinarily they grab and push you forward in the seat. There was no such sensation other than a feeling the anti-skid was cycling and the aircraft did not appear to be slowing. I believe the nose was pointed straight down the runway and the touchdown had the nose just left of the center line. On touchdown the aircraft began to immediately slide to the left. I believe the aircraft hydroplaned after landing. The First Officer depressed full right rudder with no effect. First Officer was slow to go into reverse so I came on the controlsset max reverse and followed full right rudder yet the aircraft continued to slide left and the left main mount left the prepared surface. I used nose wheel steering to bring the aircraft back toward center line. All this happened immediately after touchdown or so I believe. As we continued down the runway with both of us standing on the brakes the aircraft began to slide toward the right side of the runway. With full reverse full manual brakes and what I believed to be full left rudder it required nose wheel input to keep the aircraft from leaving the right side of the runway. At no point in time did I feel the aircraft nose was pointed at or mostly toward either side of the runway from initial touchdown to stop.As we continued down the right side of the runway the aircraft still did not appear to be slowing normally. Approaching the high speed taxiway on the right side of the runway I elected to allow the aircraft to veer onto the taxi way. We had finally slowed where we were able to bring the aircraft to a stop. We were not 100 percent sure the left main mount had left the prepared surface so we discussed the possibility and the possibility of blown tires. Tower asked if we needed assistance. We did not note any usual indications or issues all instruments appeared normal. With the exception of the anti-skid fault light. I allowed the aircraft to roll forward checking the brakes which appeared to operate normally at slow speed and we had no indication of a deflated tire. I decided the aircraft could be taxied to the gate to deplane the passengers safely at slow speed and was cleared by Tower to do so. We also informed Tower there may be FOD (Foreign Object and Debris) on the runway. Uneventful taxi to parking with good clear area all the way into the gate. Performed the parking checklist then left the flight deck to check on the passengers and flight attendants. No injuries were reported. One flight attendant said she was a little shaken. Conferred with base ops then did a walk around with the contract mechanic. Called Company maintenance and made maintenance write ups.


Synopsis: B737 Flight Crew reported a hard landing which resulted in a temporary loss of control on roll out and the aircraft's left main gear left the runway.