B737 MAX 8 flight crew reported electric stabilizer trim failed during descent. Flight crew used manual trim for approach and landed uneventfully.
Synopsis
B737 MAX 8 flight crew reported electric stabilizer trim failed during descent. Flight crew used manual trim for approach and landed uneventfully.
Narrative
We were descending on the ZZZZZ Arrival into ZZZ [Airport]. The Captain was Pilot Flying and I was PM. ATC gave us a clearance; fly direct to ZZZ VOR; and cross it at FL270; the further descent to FL240. We complied with this clearance. As the aircraft leveled at FL240; it dipped below this altitude and then began a slow climb. The Captain immediately intervened; as the aircraft had maybe climbed a couple hundred feet. The autopilot was disconnected; and he used manual inputs to bring the aircraft back into a descent. In this moment we were both trying to figure out why the aircraft had begun to climb. Airspeed was increasing and the Captain attempted to trim the nose up; which he was unable to do. He asked me if my pitch trim worked; which it did not. He then asked if I could see any circuit breakers popped; which I could not. He called for the PITCH TRIM FAIL QRH procedure; which led us through the various steps. We informed ATC of this; and further requested priority handling. The Captain hand-flew the aircraft to the airport; we requested a long final to configure for a Flaps 15 landing. We landed and taxied off the runway; were inspected by ARFF (Airport Rescue and Firefighting); where the brakes were inspected; and then continued on to the gate. Given the high workload; ATC; Passengers; F/As; and Dispatch were all informed of the events taking place; as time permitted. Very thankful for this successful outcome.I'm not sure that anything could have been done to prevent this. Possible closer Maintenance inspection on intervals of motors. It was informed to me the day after this event that thisoccurred due to an electric trim motor failure.
Second reporter narrative
During descent into ZZZ on the ZZZZZ RNAV Arrival; we were assigned a clearance to cross ZZZ [VOR] at FL270 then continue descent to FL240. We crossed ZZZ [VOR] at FL270 in VNAV PATH. I hit ALT INTERVENTION to continue descent. As we approached FL240 the aircraft descended below FL240 to approximately FL238 then began a recovery to FL240. During this recovery the aircraft's pitch increased and climbed above FL240 to approximately FL243. I disengaged the autopilot and manually flew the aircraft (during this time we were given a clearance to descend via the ZZZZZ). Once I had control of the aircraft; I began the descent and noticed the speed began to increase quickly. I attempted to trim the nose up slightly and noticed my trim switch was not working. I then informed the FO (First Officer) and asked him to try his trim switch. His switch did not work either. I realized we had a Stabilizer Trim inop; and called for the QRC Stabilizer Trim inoperative". We successfully completed the QRC and requested vectors for a long final to get the aircraft configured and stabilized for the Flaps 15 landing. After we were configured; we used the trim wheel to manually trim off any additional pressure. We made an uneventful Flaps 15 landing with autobrakes MAX. We cleared the runway and had crash; fire; and rescue personnel do a visual inspection of the aircraft before proceeding to the gate.After completing the QRC I notified the Flight Attendants and informed them that we had [requested priority handling]; landing should be normal but slightly faster than what they are used to on the touchdown and that we would be landing within the next 10 minutes. We notified Dispatch via ACARS. We also made an announcement to the Passengers before landing informing them that out of an abundance of caution; we have advised ATC and that after landing fire trucks would be seen following us to the gate.Electric stabilizer trim failed during descent. This was a mechanical event. I'm not sure much could have been done to prevent this event. I am glad that we trained in a very similar scenario during training a few years back and I was able to use knowledge learned during that training cycle."
More incidents for this aircraft family →
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.