B737 MAX 8
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 200; Flight Crew Type 16800
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Weight And Balance
Air Traffic Control Provided Assistance; Flight Crew Landed As Precaution; Flight Crew Diverted; Flight Crew Overcame Equipment Problem; Flight Crew Took Evasive Action; Flight Crew Requested ATC Assistance / Clarification; General Flight Cancelled / Delayed; General Maintenance Action
Aircraft
At cruise; we had a 'Stab Out of Trim' light. The QRH was run and we determined that we had to land the aircraft using manual trim. We coordinated with Dispatch and ATC for a diversion to ZZZ. An initial decision was made to reduce fuel to max landing gross weight by holding. After several turns in holding and in coordination with Dispatch and Operations Center Chief Pilot; the decision was made to exercise Captain's authority and proceed to ZZZ for an overweight landing; rather than continue to hold for the two hours it would take to burn down to max landing gross weight. We were vectored to a 20 NM final for Runway XXL and had an uneventful approach and landing. Brake cooling was accomplished and we were able to do a normal taxi and park at the gate. Flight Attendants and Passengers were kept aware of our situation with regular updates.
Reporter stated that the Stab Out of Trim light was likely a result of the integrity monitoring system detecting a discrepancy between the main trim motor and the position of the stabilizer. The trim motor would then be automatically disconnected from the system. Reporter stated that the manual trim functioned normally for the remainder of the flight. Reporter did not know the root cause of the event.
B737 MAX 8 Captain reported the electric trim for the stabilizer ceased functioning; causing a diversion and overweight landing.