B757-200
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 150; Flight Crew Total 14000; Flight Crew Type 4300
Time Pressure; Human-Machine Interface; Communication Breakdown; Troubleshooting
Aircraft Equipment Problem Critical
Flight Crew Overcame Equipment Problem; General Maintenance Action
Aircraft; Company Policy; Procedure; Human Factors
When loading speed info into the climb page; we received a 'standby one' message in the FMC scratch pad that would not clear for several minutes. During that time the route disappeared from the map and the route and legs pages were empty of all but origination; destination and flight number. Any attempt to load a route caused the 'standby one' message to reappear. We were unable to locate guidance in the QRH or Flight Manual that addressed other than a temporary 'standby one.' Attempts to communicate with Dispatch and Maintenance Control through ARINC via SELCAL took approximately 25 minutes to complete. In the meantime; we started troubleshooting on our own by first pressing the First Officer's FMC switch to alternate. This caused the message to go away; but it returned as soon as we tried inputting route info. We returned the First Officer's switch to normal then attempted same procedure with Captain's switch and getting the same result. Once we eventually established communication with Dispatch and Maintenance they had us repeat that same process with the Captain's side. This time the procedure seemed to work; however; it was very; very slow; taking several minutes before it would accept more than one waypoint and displays the route in map mode. Then it took several more minutes before we were able to load the climb; cruise or descent pages. When one page was able to load; it would take several minutes before we could load the next. I am concerned about the amount of time it took to get the communication established with Dispatch and Maintenance. Aren't we supposed to be able to quickly communicate with the company at all times during flight? Additionally; more info should be available in the Flight Manual regarding this FMC issue.
When the FMC CDUs stopped functioning and the route pages and map display disappeared a B757-200 flight crew attempted to contact Dispatch and Maintenance Control for assistance. This attempt met with significant delay and the crew attempted unsuccessfully to resolve the problem without maintenance guidance. When; after 25 minutes; communication was established functional but very slow use of the FMS was restored.