Date: 201701
Local time of day: 0001-0600
Location: ZZZ.Airport, US
Aircraft: B777-200
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Parked
Aircraft component: EICAS/EAD/ECAM
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Technician
Reporter qualification: Maintenance Airframe; Maintenance Powerplant
Human factors: Human-Machine Interface; Troubleshooting
Anomaly: Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew; Person Maintenance
When detected: Pre-flight
Result: General Maintenance Action
Contributing factors: Aircraft; Procedure
Primary problem: Procedure

Narrative: I was called up to flight deck; when I entered the captain said he had an issue that the ATC Message Block would not clear on the primary engine display screen although it has been accepted. It would momentary clear when printed but show again a few seconds later. The message was frozen on screen; it would not clear/ reject. I had not seen this issue before; I did mention that a possible problem could be something entered incorrectly (i.e. a space or incorrect character) will lock up the Controller Pilot Data Link Communication (CPDLC)/ DATA LINK system. Can we check? No response. I then suggested resetting Air Data Inertial Reference Unit (ADIRU) or [other] circuit breakers but if I did that he would lose his flight plan and have to reenter it. He did not want to do that but asked if I could reset the Data Communication Management Function (DCMF) because he believed that needed to be accomplished by maintenance.I accomplished the DCMF reset by selecting the COMM on the Display Select Panel; then using the mouse pad went to the Manager screen; then Master screen; and selected DCMF RESET; COMFIRM RESET. No help. The captain then called [operations control] asked for help; they patched in [maintenance control]. Talking with them no resolution was found trying different thing. The Second R. First Officer suggested to enter a second flight plan to clean up any possible errors; at this time the captain and first officer were going back through his flight plan and noticed the ORIG station was ZZZ and DEST station was ZZZ; he change the DEST to ZZZZ. No Help. The R. First Officer found in the QRH to change the FMC selector to LEFT; AUTO; RIGHT; AUTO waiting 2 seconds at each location; (ref QRH Supp.) the First Officer accomplished this. No Help. After they did that; I asked if I could go back into the COMM; MANAGER screen as before; but this time I selected the DATA LINK SYSTEM RESET; COMFIRM RESET; (the Captain said this time that this is the reset that maintenance has to do not the DCMF reset) then selected DCMF RESET; CONFIRM RESET; on the same screen. This time after resetting both; the ATC Message Block cleared from the Primary engine screen and did not return. When the problem was fixed the [operations control] and [maintenance control] disconnected from the call. At this point the Captain said we need to write this up in the log book due to we are on delay. Then the crew entered the flight plan back into the FMC (I think as a second flight plan). As they were doing this I tried to find a Maintenance Manual reference for a sign off but couldn't. The DCMF and DATA LINK resets I accomplished were both 'soft' resets; as no circuit breaker were pulled; the Maintenance Access Terminal (MAT) was not accessed and no status messages were displayed.I did not use an Aircraft Maintenance Manual in my sign off due to the data link system reset that is called out in the Fault Isolation Manual (FIM) requires you to pull the AIMS L and R Circuit Breakers (8 total) for 2 minutes then reset all circuit breakers. I did not do this 'Hard Reset' of the system. I had selected to do the reset option in the COMM. Manager menus that as I have found later would be a crew function not a maintenance function.My plan originally was the use [a] FIM Task; but the captain did not want me to do a complete reset by pulling the AIMS cabinet circuit breakers.Better understanding of what is a flight crew and maintenance crew for data link system resets using COMM; MANAGER (no circuit breakers pulled) or a maintenance manual ref for doing this kind of reset.




Synopsis: A B777-200 Technician reported being unable to find the proper procedure to clear a fault that appeared on the primary engine display.