B777-200
Maintenance Airframe; Maintenance Powerplant
Confusion; Communication Breakdown; Human-Machine Interface
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural MEL / CDL; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Human Factors; Procedure; Aircraft; Equipment / Tooling
B777-200 aircraft arrived ZZZ January 2015. Myself [as Mechanic X] and Mechanic Y were assigned the ETOPS inspection and inbound logbook items. Had EICAS message: Bleed High Pressure Shut-off Valve (HPSOV) Right Engine. Interrogated [aircraft's] Maintenance Access Terminal (MAT); insufficient time to repair; optioned for MEL Deferral (DFRL) [Chap] 36-3a. Aircraft departed to ZZZ to ZZZZ January 2015 in AM. Departing ZZZZ following day; pilot reported Bleed 'Off' engine right; 'On' at cruise power setting. We were using the maintenance tablet to follow procedure MEL 36-3a on how to lock out the HPSOV [on the] right engine. The first illustration that we scrolled to showed the valve position for the wrong valve; figure-1; causing us to lock out the wrong valve.[Recommend] When pulling the MEL on the desktop computer to follow the procedures on how to lock the HPSOV; a figure is attached to the MEL; clicking it will take you to the correct valve position. It is not confusing; however; on the maintenance tablet you have to scroll to the figure; leading the user to assume the figure shown is related to the referenced MEL. That is not the case in this situation. The figure shown was the wrong valve; which contributed to the error.
B777-200 aircraft arrived ZZZ January 2015. Mechanic X and [myself as] Mechanic Y were assigned the ETOPS inspection and inbound logbook items. EICAS message BLEED HPSOV R ENG. We interrogated MAT and determined insufficient time to repair. Optioned for MEL deferral using MEL 36-3A. Aircraft departed ZZZ for ZZZZ. Pilot reported BLEED OFF ENG (R); 'On' at cruise power setting.We used the Maintenance tablet to follow procedure MEL 36-3A on how to lock out the HPSOV on the right engine. The illustration displayed was for the Pressure Regulating Shut-off Valve (PRSOV); causing us to lock out the wrong valve. [Recommend that] when checking the MEL on the desktop computer to follow procedures on how to lock out the HPSOV; a figure is attached to the MEL and clicking it will take you to the correct illustration. IT'S not confusing; however; on the maintenance tablet you have to scroll to the figure. If you don't; you are led to believe the figure displayed is related to the referenced MEL; which contributed to the error.
Two Line Aircraft Maintenance Technicians (AMTs) explain why different procedures must be used to access the correct MEL illustration for deferring a High Pressure Shut-Off Valve (HPSOV) on a B777-200 engine when using a desktop computer or maintenance tablet. They had locked out a Pressure Regulating Shut-Off Valve (PRSOV) on the right engine instead of the HPSOV.