EMB-175 flight crew reported returning to departure airport after experiencing failure of the WOW (Weight on Wheels) system that prevented the retraction of the landing gear.
Synopsis
EMB-175 flight crew reported returning to departure airport after experiencing failure of the WOW (Weight on Wheels) system that prevented the retraction of the landing gear.
Narrative
Departed the gate [and] took off shortly after. The aircraft handled normally; but as soon as we lifted off there was a noise coming from under the flight deck seats for around 2 seconds; which then ceased. After 'Positive Rate' I called for 'Gear Up' and the First Officer attempted to actuate the landing gear selector lever up several times reporting it would not move. I also attempted to actuate it unsuccessfully. We connected the Autopilot; formulated a basic plan; briefed the cabin crew and passengers; sent an ACARS to the Dispatcher; and communicated with ATC to burn off excess fuel and to make a return to ZZZ. With no EICAS message for the fault; we searched the QRH to find the applicable checklists and ultimately ran the 'Gear Lever Cannot be Moved Up' and the linked 'LG WOW Sys Fail;' 'LG WOW Sys Fail Descent' and 'LG WOW Sys Fail Landing' checklists while receiving vectors and briefing for our requested approach into ZZZ. We applied the landing considerations from all aforementioned checklists and discussed/implemented additional precautions; including a gentle descent rate on touchdown and letting the nose wheel down carefully. The aircraft landed below max landing weight. It felt normal and performed normally on landing/taxi and we taxied to the gate. Crash Fire Rescue escorted us as far as the ramp. We complied with all after event requirements from the flight manual; a maintenance entry was created and we discussed what we had experienced with maintenance who met the aircraft; and we performed an evaluation of our fitness for duty before continuing our duty day.Unknown mechanical breakdown. The QRH is written in a way that suggests a landing gear weight-on-wheels system fail (the 'Gear Lever Cannot Be Moved Up' checklist points to 'LG WOW Sys Fail' checklists); but the aircraft did not indicate any failures via EICAS. LG WOW Sys Fail could be alerted via the EICAS to simplify handling of similar problems.
Second reporter narrative
The aircraft performed normally on the ground. As soon as we lifted off of the ground; a noise was noticed coming from under the seats that lasted around two seconds. After the two seconds the noise disappeared. I called 'positive rate' [and] the Captain called for 'gear up.' At that point I tried to position the gear selector lever to the up position. I informed the Captain I could not get the lever to move after two to three attempts. The Captain reached over to try and move the lever as well; and was unsuccessful in his attempt. The Autopilot was connected to ease work load. We began to formulate a basic plan; briefed the crew members; passengers; sent a message to the Dispatcher via ACARS; and communicated with ATC to get burn off fuel and run the appropriate checklist. No messages were displayed on the EICAS so we searched the QRH for any applicable checklists. We found the 'Gear Lever Cannot Be Moved Up' checklist and began to run that. Linked to that checklist were the 'LG WOW Sys Fail'; 'LG WOW Sys Fail Descent'; and the 'LG WOW Sys Fail landing' checklists. After these checklists were completed we began to set up for our request approach into Runway XXL. We applied all considerations from the checklists we had ran; and implemented additional precautions for the landing. This included a minimum decent rate to touchdown; and letting the nose wheel down to the runway as gently as possible. The aircraft was landed below maximum landing weight. Once on the ground; the aircraft performed normally. Once back at the gate we complied with all after event actions required within our manuals; and we evaluated our fitness for duty.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.