Date: 201709
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Light: Night
Aircraft: Regional Jet 700 ER/LR (CRJ700)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Ferry / Re-Positioning
Flight phase: Takeoff / Launch
Airspace: Class C ZZZ
ATC / advisory: Tower ZZZ
Aircraft component: Gear Extend/Retract Mechanism
Component problem: Failed; Improperly Operated
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Troubleshooting
Second reporter function: Pilot Flying; First Officer
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Maintenance
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Diverted; Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport; General Maintenance Action
Contributing factors: Aircraft; Equipment / Tooling; Human Factors
Primary problem: Human Factors

Narrative: We (flight crew) went on-call at [early morning]. We dutied -in [two hours thirty minutes later] to re-position an aircraft. That aircraft had an inoperative APU and was located on the hangar ramp. The hangar did not have ballast (required) and we were told fuel would take a long time. Sector Manager recommended we taxi over to get fuel and ballast. We started the right engine only (yes; 2B on for flaps-up taxi) and taxied over and we hot fueled the aircraft; got 450 LBS ballast and then pushed. We flew to destination and had a radar failure immediately after takeoff flying into the decaying thunderstorm. We landed in our destination and handed off the aircraft to the next crew.We were then put to rest for 10 hours [mid-morning]. I can't just put myself to 'rest' [mid-morning]. The above is to indicate that this was a long (but legal; 2 duty-period) day.We returned to the airport [at dusk] and found another APU-less aircraft. Coordination for ballast and a Huffer was more difficult than [in our prior flight]. The company bottle did not work and we had to get [a contractor ground service] to come to the hangar with their Huffer. We finally got the left engine started. ACARS weight and balance transmission was non-functional (OSC issue) and complicating matters was the fact that the dispatcher calculated ballast required with 2 flight attendants on board - which we did not have. The door was closed by the time I realized this issue; so we requested the dispatcher recalculate and it was determined that we needed more sand bags. Again; to speed the process; we taxied the aircraft over to the gates area to pick up more sand.Finally taxiing to the runway; when the First Officer selected XFlow Auto Override to Manual; we received an XFlow pump failure. We stopped at the end of the runway and I conferred with Dispatch and Maintenance Control. We decided that it was deferrable and that we could continue with an entry in the [logs].Shortly after takeoff; the First Officer called for gear up. I grabbed the handle and it would not move. I pulled it out; I pulled it up - it would not move. Shortly thereafter; we received a 'WOW INPUT' caution message. I told the First Officer not to exceed 200 KTS and told ATC that we had a retraction issue; did not want to climb above 5000 FT and request box vectors around the airport. I ran the QRH checklist; but immediately stopped because it basically starts with 'Prior to landing...' I contacted the [company] and Maintenance Control confirmed no GEAR DISAGREE; then said talk to your dispatcher. Dispatcher and I agreed we did not have the fuel to fly to [our destination] with the gear down; so we should return [to the airport].The QRH references that nose wheel steering may be inoperative and brakes (anti-skid) may be an issue so I decided to [relay this information to ATC]. We were vectored around for an uneventful landing.The QRH was sequentially completed -multiple steps at multiple phases of flight; with some on the ground prior to shut down. With the engines shutdown back on the hangar ramp; maintenance began inspecting. After consulting with the Maintenance Diagnostics Computer; the proceeded to find a tests article in the nose wheel system. I don't know what it is / was; but they showed me a small 1 inch block of metal that they place on a WOW sensor to test the aircraft's systems. I have no idea where that sensor is - and I doubt the First Officer does either. In other words; there was no way we knew to look for that thing and the gear was not coming up with it there. I did verify three gear pins prior to accepting the aircraft. That test item was removed; the XFlow pump deferred and we finally flew home. Essentially 19+ hours in one workday.Landing gear that would not retract due to a maintenance oversight and a long day consisting of two duty periods were causes [that led up to this predicament].I'm sure procedures are in place for mechanics to capture this error; the same way we now confirm gear pins in the flight deck. I must say that the maintenance lead seemed kind of lax in his demeanor and was not very familiar with the aircraft (while on ground power; flight crew in the first class cabin and maintenance in flight deck; he had to ask us how much fuel was on the airplane).


Second narrative: We arrived at the maintenance hangar and were told that the aircraft was ready to return to [the airport] and there was a technician at the aircraft trying to get the APU started but if he wasn't able to. They would defer the APU so that we could depart as soon as possible. They couldn't get the APU started so the decision was made to defer the APU. So we began the process of deferring the APU and coordinating for a GPU; Air Cart for the engine start and fuel.While preparing for the departure and coordinating with maintenance and ground personnel I noticed there was a PROX SYS FAULT 1 status message posted but during all the interruptions from maintenance; and ground personnel failed to ask the Captain; if he was aware of the message. We discussed the other MEL items and made sure they were listed on the release.We proceeded with the checklist and started the left engine in accordance with the checklist and the first flight of the day procedures. We elected to perform the cross-bleed start after we began our taxi and once we were clear of the ramp. Next; we called ground and received taxi instructions to runway. Once on the taxiway I started the right engine and then preformed the takeoff briefing. The Captain called for the Before Takeoff checklist to the line and I began the flow. I pressed the XFLOW AUTO OVERRIDE switch and an XFLOW PUMP caution message appeared. We came to a stop short of the departure runway and informed the tower that we would need time to complete the checklist. We reviewed the procedure in the QRH and we both agreed that it didn't apply since we were not in flight but need to consult maintenance and the dispatcher. After consulting with maintenance and the dispatcher; the decision was made to defer the XFlow Pump and continue.We completed the required checklist and departed. Take off and initial climb was normal; the pilot not-flying; (PNF) called; 'positive rate' and I responded with; 'gear up and speed mode.' After attempting to move the gear handle to the up position the PNF stated the gear handle wouldn't move. I acknowledge and called for heading mode to comply with the towers departure instructions. The PNF tried to move the gear handle to the position and advised that the gear handle wouldn't move. After the second attempt to move the gear handle a WOW INPUT message posted on the crew alerting system. At this time we were instructed by Tower to contact departure. I called for the autopilot on and followed the normal flap retraction schedule and maintained the airspeed below 200 KIAS.The PNF contacted departure and advised them of the situation and told them that we would like to maintain 5000 FT and would like vectors to remain in the vicinity of [airport] while we completed the checklist and would advise them of our intentions. The PNF delegated the communications with ATC to me the Pilot Flying while he completed the checklist and contacted Maintenance on the radio. After communicating with Maintenance and the dispatcher it was agreed upon the best course of action was to return to the airport. We then informed ATC of our intentions to return and the Captain elected to [exercise his authority] as a precaution. We completed the WOW INPUT message checklist while being vectored for the ILS. We reviewed the procedures for after touchdown; briefed the approach and completed the arrival checks. We landed and taxied back to the maintenance hangar without incident. Maintenance personnel meet us at the hangar and came on board the aircraft. After describing what happen they began to trouble shoot the problem. They were able to determine that the problem was either a sensor or the rigging was out of limits from the on board computer. Shortly thereafter a maintenance technician came up to the cockpit with what appeared to be a fabricated piece of metal that was left on a sensor from the work they had completed earlier and had not been removed from the sensor after the work had been completed earlier. After the piece of metal was removed from the sensor the maintenance personal were able to clear the faults and the system checked out okay. After all required procedures were completed and paper work signed off we departed without further incident.Threats that I feel contributed to this event was all of the coordination between the maintenance; and ground personnel that we don't normally do. In normal passenger operations things such as checklist are completed while everyone else completes there required duties. As pilot we check and verify that task are done. Normally they are completed on time and with little input from us. Picking up an aircraft from maintenance is outside of how we normally operated. While all the checklist were completed I feel that all the interruptions contributed to us not discussing the PROX SYS FAULT 1 status message.The other threat that occurred was the XFlow Pump message while completing the before takeoff checklist. We were probably focused on that message and when I stated EICAS check and cleared on the before takeoff check I was focused on the XFlow Pump message instead of all of the messages that were posted.I feel that it would have been better to ensure things like fuel; ballast; GPU; the Huffer cart were all in place prior to completing the required checklist and briefing. Checklist were completed as time allowed in-between talking with maintenance; dispatcher; and ground personnel; which I feel allowed us to miss the PROX SYS FAULT1.While it's the Captain responsibility to set the tone and pace of the cockpit environment; I can make recommendations from what I've learned about minimizing distractions and slowing the pace down. I have asked to slow down while taxiing or in the air but it also applies from the time you so up to the aircraft.


Synopsis: CRJ-700 flight crew reported that after takeoff the crew was unable to raise the gear handle; (the gear handle would not move).