B777-200
Maintenance Powerplant; Maintenance Airframe
Training / Qualification; Situational Awareness; Communication Breakdown
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Aircraft; Human Factors; Procedure
Was assigned to change [Cabin Passenger Doors] 4-Left (L4) and 4-Right (R4) Door slides. Had Maintenance Manual reference in hand and used reference during maintenance. After slide was changed; verified all door operations were in order and operating properly; however I was complacent in continuing on with the Maintenance Manual reference after all Operational Checks verified normal. The last step after the complete installation was done is to 'check Emergency Power Assist System (EPAS) reservoir pressure gage' to verify correct pressure level in bottle. I did not see that subtask listed at the time and moved on about my day. The reason the slide was being changed is because it was previously deployed. Maintenance personnel detected the low bottle pressure at the gate prior to revenue flight. The event occurred due to my complacency in not fully reading the Maintenance Manual reference all the way through until the next section (task). I did have the manual reference in hand during the maintenance and read it thoroughly step by step while accomplishing the install of the new slide. After the slide was installed and checks normal; I just figured that was completed and felt comfortable about it being done. I have never changed a slide before after it had been blown and for whatever reason it just didn't occur to me to check the EPAS bottle. Normally I am very conscientious about these things and yesterday I was not. I will read the entire section of the task at hand when performing maintenance to ensure all checks are completed as required.
Overlooked step in Maintenance Manual (M/M). Working with more then one Aircraft Maintenance Technician (AMT); overlooked M/M step. When working with more than one AMT; I should also read the M/M. Aircraft was taken out of service.
Two mechanics and one Inspector report about an Emergency Power Assist System (EPAS) bottle that was not re-serviced on a B777-200 aircraft after a slide replacement. The same slide also fell out of the slide pack the next day at the gate due to a foreign object.