Date: 202103
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: Turbulence
Light: Night
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Cargo / Freight / Delivery
Flight phase: Climb; Initial Climb
Airspace: Class B ZZZ
Aircraft component: Main Gear
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Maintenance
Detector: Person Maintenance; Person Flight Crew
When detected: Aircraft In Service At Gate; In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Returned To Departure Airport; Flight Crew Landed in Emergency Condition; Flight Crew Requested ATC Assistance / Clarification; General Maintenance Action; General Flight Cancelled / Delayed
Contributing factors: Procedure; Aircraft
Primary problem: Procedure

Narrative: First leg was a block turn back in ZZZ. Fluid leaking under right main gear. Maintenance performed the following corrective action: REMOVED AND REPLACED RH GEAR TRIM CYLINDER RELIEF VALVE. I asked the maintainer whether he needed to bleed the brakes since he cracked the closed system. He told me to cycle the brakes and if they felt good we were good to go. Legs 2 was the subsequent takeoff. After takeoff; gear handle would not move. QRH procedure offered no resolution. Declared priority handling. Conferenced maintenance and Operations Control in the air. Uneventful landing ZZZ Runway XX. The following was the maintenance corrective action: CONFIRMED FAULT; GEAR HANDLE WILL NOT RETRACT IN ANY CONFIG. T/S SYSTEM AND FOUND MLG HYDRAULIC INTERLOCK CYLINDER NOT EXTENDING WITH SYSTEM 3 PRESSURE; WHICH MECHANICALLY INHIBITED TRAVEL OF GEAR HANDLE. DUE TO TRIM CYLINDER RELIEF VALVE RECENT CHANGE; SUSPECT RESIDUAL AIR IN SYSTEM. BLED TRIM CYL RELIEF VALVE; NO AIR. BLED HYD FUSE; FOUND A SIGNIFICANT AMOUNT OF AIR-ENTRAINED FLUID. BLED INTERLOCK CYLINDER. NO FLUID CAME OUT AT FIRST; FOLLOWED BY A SIGNIFICANT AMOUNT OF AIR ENTRAINED FLUID. AFTER BLEEDING; SYSTEM WORKS NORMALLY; INTERLOCK EXTENDS AND RETRACTS AS NORMAL; REF [type aircraft] AMM 32-31-05-2 AND AMM 32-37-03-2. JACKED ACFT AND SWUNG GEAR TO VERIFY A POSITIVE FIX. GEAR SWINGS NORMALLY WITH CORRECT INDICATION MULTIPLE CYCLES. ACFT OK FOR SERVICE. Is it reasonable to draw a connection between leg 1 and leg 2 as to cause and effect for the gear handle stuck in the down position? After extensive research; I wasn't able to find a definitive answer as to a correlation. However; during my research; I discovered that it is maintenance procedure to bleed the hydraulic system after relief valve replacement. Interestingly enough; I even asked the mechanic about this. He response was to me was to set and release the brakes a few times; and then he asked me if they 'felt okay'. When I replied that 'They seemed normal' he said 'You're good to go'. Obviously; I wasn't good to go. I should also mention that after the job was declared complete; I went down to observe the new valve. There was hydraulic fluid everywhere including a 3 foot diameter puddle under the valve. As the Captain; when I ask specific questions about a maintenance procedure; it is unacceptable to be given incorrect information by maintenance or be lied to by maintenance. Why wasn't the procedure completed correctly? Why isn't there a check and balance system in place to verify mechanics are completing maintenance actions? I demand an answer to these questions as well as why there was so much air in the hydraulic system which inhibited gear handle movement.


Second narrative: Crew contacted me via radio; shortly after takeoff. Captain advised that they were unable to raise the gear and will be returning to ZZZ. Captain advised gear was down and locked but said he will [advise ATC] as a precaution. Earlier; flight did a block turn back due to a hydraulic leak at the gear. Maintenance repaired the leak by replacing a valve. Not sure; at this time; if that played a part with the gear not retracting. Flight landed safely and Manager was notified.


Synopsis: Heavy aircraft flight crew reported a landing gear malfunction that resulted in a return to the departure airport.