E175 flight crew reported ground personnel indicated aircraft movement when the chocks were pulled after previous maintenance work on the hydraulic accumulator. The Captain turned on hydraulic pumps and cycled parking brake; then was notified of the uncommanded aircraft movement by the ramp personnel.
Synopsis
E175 flight crew reported ground personnel indicated aircraft movement when the chocks were pulled after previous maintenance work on the hydraulic accumulator. The Captain turned on hydraulic pumps and cycled parking brake; then was notified of the uncommanded aircraft movement by the ramp personnel.
Narrative
Prior to close; we had low Sys 2 Emer Accumulator pressure indication on startup so submitted a write-up and called maintenance. Maintenance arrived at aircraft and cycled the parking brake numerous times according to their maintenance procedure for the indication. The aircraft was cleared to return to service and then we closed and pulled the jet bridge. CA was unable to get a hold of the rampers so CA cycled the parking brake with the hydraulic pumps on and the brakes held to generate the out time. Shortly after we got a hold of the ramper who said company safety was called as the aircraft moved when the chocks were pulled. After talking to company safety; we continued on as normal. Cause: Both the CA and I were fairly certain did not move when the brake was cycled to generate the out time; however it may have moved prior to that due to the loss of pressure in the brake system from the maintenance procedureSuggestions: In the future; CA will communicate to the ramp crew that maintenance has worked on the brake system. I have also reviewed the SOP for the brake release and found that despite the culture being to get the brake dropped; even cycling the brake requires communication with the ground crew; therefore in the future I will make sure CA communicates prior to cycling brakes. Additionally; providing the ground personnel with better communication equipment would help to minimize communication issues. Often it is hard for us to determine if it is hard for them to hear us or they are not on headset yet.
Second reporter narrative
[Report narrative contained no additional information.]
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.