Date: 202108
Local time of day: 1201-1800
Location: ORD.Airport, IL
Flight conditions: Marginal
Weather elements / visibility: Rain
Aircraft: B737 MAX Series Undifferentiated
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
ATC / advisory: Ground ORD
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Human factors: Distraction; Situational Awareness
Second reporter function: Pilot Flying; Captain
Anomaly: Ground Event / Encounter Weather / Turbulence; Ground Event / Encounter Loss Of Aircraft Control
Detector: Person Flight Crew
When detected: Taxi
Result: Flight Crew Regained Aircraft Control
Contributing factors: Weather; Airport; Aircraft; Human Factors
Primary problem: Weather

Narrative: We almost slid off a taxiway.  After landing [Runway] 27R in rain; we were cleared on C1 and proceeded southbound on Z.  At the first right turn; I heard the Captain say; 'Oh [no]' and looked up to see us slowly sliding straight for the edge lights as my CA heroically held full right tiller and popped the reverse.  We also heard a loud; sustained grinding noise from the nose wheel as we slid across its tread.  The taxiway was noticeably wet with relatively new (slick) paint markings; plus we were operating a MAX that carries extra energy while taxiing.  We informed ATC of our issue as we were able to return the airplane to the centerline.  We continued to the gate after checking with our FA and PAX (all were well).  Upon parking; my CA went outside and was able to verify that no contact was made with any lights or grass; and the airplane was undamaged.  Flight concluded uneventfully.We were vigilant regarding the weather and ready for unexpected things while flying; but our attention became divided on the ground and our senses softened.  Plus; Runway 27R is not a typically assigned runway.  Normally; a slow taxi in wet conditions; as ours was; is sufficient to keep things safe.  But in this case even that was not enough.  Additionally; we are relatively low time in the MAX (CA w X legs; FO w XXhrs); so while expecting things to be different it may also be true that our reflexes were simply not mature.We later learned from a local ORD based pilot that this corner is notorious for being very slick when wet; given the nature of the pavement; paint; and its downhill gradient.  This was news to us and would make an EXCELLENT addition to the company pages!!


Second narrative: After clearing the Runway 27R at C1 we proceeded on to taxiway Z. At the first right turn on taxiway Z; I proceeded to make the right turn to follow the taxiway centerline but the aircraft would not turn. The nose wheel began to slide. The taxiway was wet at the time. We were in a 737 MAX at idle thrust and riding the brakes. The taxi speed was between 8 and 10 knots. I managed to keep the aircraft on the taxiway with aggressive braking. The taxiway was wet and with the strong residual thrust the aircraft nose wheel could not get enough grip on the painted surface of the centerline. It also seemed like the aircraft was tail heavy and that might have reduced the weight on the nose wheel.Go even slower when taxiing the 737 MAX with wet surface conditions.


Synopsis: B737 MAX flight crew reported that while attempting to turn during taxiing the aircraft almost slid off the ORD Z taxiway due to the wet surface and a downhill slope.