Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Flight Crew Last 90 Days 511
Aircraft Equipment Problem Critical
Flight Crew Regained Aircraft Control
Aircraft
Day 3 of 3 departing in a MAX 8 after a long overnight. I was well rested and had discussed the recent MAX 8 MCAS guidance with the Captain. On departure; we had strong crosswinds (gusts > 30 knots) directly off the right wing; however; no LLWS or Micro-burst activity was reported at the field. After verifying LNAV; selecting gear and flaps up; I set 'UP' speed. The aircraft accelerated normally and the Captain engaged the 'A' autopilot after reaching set speed. Within two to three seconds the aircraft pitched nose down bringing the VSI to approximately 1;200 to 1;500 FPM. I called 'descending' just prior to the GPWS sounding 'don't sink; don't sink.' The Captain immediately disconnected the autopilot and pitched into a climb. The remainder of the flight was uneventful. We discussed the departure at length and I reviewed in my mind our automation setup and flight profile but can't think of any reason the aircraft would pitch nose down so aggressively.
B737 MAX First Officer reported that the aircraft pitched nose down after engaging autopilot on departure. Autopilot was disconnected and flight continued to destination.