Date: 201410
Local time of day: 0601-1200
Location: ZZZZ.ARTCC, FO
Flight conditions: VMC
Light: Daylight
Aircraft: B757-200
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Cruise
ATC / advisory: Center ZZZZ
Aircraft component: Rudder Trim System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Anomaly: Aircraft Equipment Problem Less Severe; Inflight Event / Encounter Fuel Issue
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: After reaching FL340; the First Officer began to trim the aircraft for the cruise portion of the flight. We noticed that when attempting to trim the rudder nose left; the trim was moving slower than usual per the trim indicator. When trimming nose right; the rate was normal. When trimming nose left again; the trim no longer moved. The rudder trim was at 3 units to the right. Nose right was tried once more momentarily and the indicator moved nose right. Trying nose left again; the trim did not move. Nose left trim was inoperative. By this time we were about 80 nm east of our oceanic gateway; the ZZZZZ intersection. We sent an ACARS message to Maintenance Control and in the meantime began to trouble shoot the problem. There is nothing in the QRH pertaining to rudder trim and we found no relief in the MEL. Maintenance Control concurred with this. As we got within 5 minutes of coast out; we informed ATC that we had issue that might prevent us from proceeding past our outbound gateway. We asked for vectors to continue working on the problem and for Maintenance Control to get back to us.  When Maintenance Control did get back to us; we discussed if we could continue or not. I told them my concern was a single engine operation with limited or no rudder trim available. Maintenance Control concurred and it was decided that we should return. The aircraft was also carrying an MEL for the right forward fuel pump being INOP. This required us to carry extra fuel. We estimated while still over the coast we would need close to 4 hours to burn down to our maximum landing weight of 198;000 LBS. Maintenance Control agreed and we requested routing back to [the departure airport] with the plan to hold near the airport. I notified the flight attendants of the issue and that we were returning. I also told them that it would be necessary to hold to burn off fuel and that we would be making a normal approach and landing. I told the flight attendants that we would be flying close to 4 hours before landing. I then made an announcement to the passengers and told them the same thing I told the flight attendants; including that the approach and landing would be normal. We did read in the FOM part 1 on page 19.1.13 the parameters for making an overweight landing. This was discussed with Maintenance Control through a phone patch; and we decided to burn down to just below our maximum landing weight before landing. We arrived over the ZZZZZ1 intersection and held for approximately 3 hours. We left the hold at 198;000 LBS and were vectored for the approach to runway XXL. The approach and landing were normal. On final; above 1000 feet AFL; I checked the gross weight and we were at 197;400 LBS. Upon meeting Maintenance at [the departure airport]; we learned the aircraft had a history involving the rudder trim. The passengers were rebooked and we dead headed to [the destination] the next day. Parts and a crew were flown into [the departure airport] to fly the aircraft to [the original destination].




Synopsis: B757-200 flight crew reported abnormal rudder trim reactions that led to a return to departure airport.