Date: 201812
Local time of day: 1201-1800
Aircraft: A321
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Aircraft component: Elevator Trim System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Communication Breakdown; Troubleshooting; Workload
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Overcame Equipment Problem
Contributing factors: Aircraft; Manuals
Primary problem: Aircraft

Narrative: The First Officer did an outstanding job flying the aircraft; setting up the MCDU for the approach; and communicating with ATC during the arrival until I was ready to take back control. He properly made this his first priority and avoided distraction; thereby allowing me to focus on managing the emergency. He was the first to suggest holding on to the pitch trim wheel and; later; [advising ATC]. The First Officer should be specifically and highly commended.No one I talked to during or after this event had ever heard of an uncommanded stabilizer trim malfunction on an Airbus fly-by-wire aircraft before. This event should be documented and a de-identified summary should be published to [Company] pilots so that others can learn from this event.The pagination of the System Reset Tables in COM Book 2 was confusing and delayed my ability to determine that there were no applicable resets for several minutes. It has been mentioned by Flight Operations Management that there is the intent to eventually provide tail number-specific QRHs in the cockpit and thereby return towards Airbus manufacturer philosophy regarding Abnormal/Emergency Procedure and ECAM handling. This must be properly implemented; and it carries risks because the manufacturer-provided QRHs are not compatible with our current procedures; manual set; or ECAM handling philosophy; so these items would require appropriate modifications. But properly implemented; returning to tail number-specific QRHs would solve the issue I encountered; and many others.The Safety Department should determine whether or not a brace command was issued by flight attendants; without flight crew awareness; and contrary to what I believed were my very clear instructions. For example: did this not occur; did it occur due to a miscommunication between myself and the Lead FA; did it occur due to a miscommunication between the Lead FA and the other FAs; or did a FA deliberately disregard my instructions? If this occurred due to a miscommunication; I would like to be made aware of it so we can learn what went wrong and how to communicate better in the future. If this occurred due to a deliberate decision by a FA to disregard my instructions (but then not inform us they had done this); the FA should be debriefed in a non-punitive manner to determine the reason for that FA's decision and then to ensure that they understand: that it was not appropriate for this particular situation; what were the risks associated with doing this; and what were the risks associated with not telling the pilots they had done this.




Synopsis: A321 Captain reported QRH shortcomings and communication breakdown between flight crew and cabin attendants while troubleshooting uncommanded stabilizer trim malfunction.