Date: 202202
Local time of day: 0601-1200
Location: ZZZZ.ARTCC, FO
Flight conditions: VMC
Light: Daylight
Aircraft: B737-900
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
ATC / advisory: Center ZZZZ
Aircraft component: Elevator Trim System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; First Officer
Reporter qualification: Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Human factors: Troubleshooting
Second reporter function: Dispatcher
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Returned To Departure Airport; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Overcame Equipment Problem; Flight Crew Landed As Precaution; General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Aircraft; Human Factors; Procedure
Primary problem: Aircraft

Narrative: After takeoff the electric trim no longer worked. We tried both PF (Pilot Flying) and PNF (Pilot not Flying) side to make sure. We followed the QRH and worked the problem with the QRH. CA (Captain) transferred controls to me while the CA got together with Dispatch; Flight Attendants and ATC for our return to ZZZZ. We could manually trim the airplane for the return flight and uneventful landing back in ZZZZ. [Priority handling was requested]. The CRM between the whole crew and ATC was great.


Second narrative: I received an ACARS from the crew shortly after departure from ZZZZ1/ZZZZ. They informed me: 'STAB TRIM NOT WORKING - WENT THROUGH QRH NQRH DID NOT FIX - MAY BE GOING BACK TO ZZZZ.'I quickly asked if they want to troubleshoot with Maintenance Control - Answered with a 'CALL ME' request - I sent them a Call ME via ACARS to dial up on XXX.X. Then I noticed they were at FL140 and sent the crew a message regarding that - we may have difficulty connecting below FL200. We were then connected via ZZZ ARINC. I quickly tried to get Maintenance Control on the line to try and trouble shoot the situation. I called Maintenance Control using the standard method - Maintenance Control/Maintenance button - 737 - Maintenance Control AIR FRAME 737. The system then dialed in and requested I punch in the nose number. After that; I told the system that it is an airframe issue. The phone started ringing and ringing; but no answer. After about a minute or so unanswered; I became frustrated and hung up to dial the Maintenance Control PRIORITY Button. There was no answer at this number either. In a panic now because I may have an inflight emergency and the crew are waiting on a radio; not knowing what is going on or whether or not I am still connected. After trying the Priority number once more and it ringing another 30 seconds; I finally get an answer. However; the Maintenance Control Controller that answered the phone was not a 737 Controller; it was a 767 Controller. He wanted to transfer me; but I told him that I may have an inflight emergency and that I needed immediate connection to someone that can trouble shoot with the crew; and that I previously called the 737 Air Frame desk to no answer. He then offered to connect to the crew. He informed the crew that he was a 767 Controller; and that he worked on 737 in the past. After a brief troubleshooting - we were all in agreement that crossing the [area] with this malfunction was not safe and we decided to divert back to ZZZZ1/ZZZZ. The crew then [requested priority handling]. I went through the normal diversion checklist and sent the crew landing data. We were landing heavy; but the crew stated they were flying a wider route to land just under MAX landing weight. The flight landed safely in ZZZZ1/ZZZZ - however the Maintenance Control response was unacceptable. Thankfully this time there was adequate time to troubleshoot; but precious minutes were unnecessarily wasted trying to connect Maintenance Control with the flight; and when we finally did get a connection; it was a Controller from a different fleet. Had this been a more time sensitive emergency; there may not have been adequate time to relay the necessary information to conclude with a safe operation. The response time may be because the Maintenance Control controllers are working from home - there is obviously decreased situational awareness as my call went unanswered in an emergency situation. This has happened several times in the past to other Dispatchers and in the name of safety needs to be addressed immediately.The Captain later called me to express his concern with the Maintenance Control response and we both thought it was in the best interest for the safety of this airline that we both file a safety report concerning the Maintenance Control response to this situation.


Synopsis: Flight Crew and Dispatcher reported communications issues after the Flight Crew elected to perform an air turn back caused by trim failure.