Commercial Fixed Wing
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Aircraft Equipment Problem Critical
Flight Crew Diverted
Aircraft
Aircraft was operating in cruise at FL 360. The left engine initially experienced a strong vibration and momentary roll back which was also noticed by the passengers and cabin crew. It appeared that that there was an approximate 20% reduction of N1. We disengaged the auto throttles and reduced power. This stopped the vibration and the engine seemed stable. We began a descent to FL240. As we started the descent the cabin tried to notify us of what happened. Since the mechanic had also gone to the cabin we opened the cockpit door and communicated what was going on. While descending we sent an ACARS (Aircraft Communications And Reporting System) message to Dispatch to let them know our situation and so they could advise of preferred diversion airports. While Dispatch was checking for diversion airports we notified the passengers and flight attendants that everything was currently stable and as long as it stayed that way we would continue to our destination. If we had to divert we would advise them what our planned diversion airport was. As both of us searched through our Jeppesen app it was discovered that the recent update and deleted all of the airport in country from our coverage. Since shutting down a currently operating engine and diverting into an airport that we had no charts for did not seem like the best course of action we decided to continue as long as the engine was stable. The engines remained stable with no noticeable vibration for the remainder of the cruise portion. The power was approximately 76% N1 and the only noticeable change was the left engine EGT and Fuel Flow was registering a larger split. All other gauges seemed normal. On our descent into ZZZZ no noticeable vibration or engine indications were noticed; however there was a brief flash of the OVERHEAD look up annunciation that was flashing for the Flight Data Recorder. This happened possibly 4 times all less than a second. The aircraft was configured for a normal landing as it seemed the engine was responding appropriately. After the aircraft started down the glide slope the Left engine vibration returned. We reconfigured for a flaps 15 landing and idled the Left engine this stopped the vibration. We landed uneventfully and taxied to customs. While taxiing the Left engine oil bypass annunciation began to flash momentarily. At this point the engine was shut down and we taxied the remaining way to customs. Upon shut down the mechanic and PIC (Pilot In Command) conducted a visual inspection of the engine and no visible damage was noticed.Left engine vibration and roll back of N1. Engine was stable at lower altitudes and power settings.The cause of the engine vibration is still unknown. The was an MEL (Minimum Equipment List) for the Left Engine A fire detection loop that was currently listed in the logbook and on the release.Power was reduced and aircraft descended. Vibration stopped until short final. It was tough to determine possible diversion airports since no airport data was currently in Jeppesen application.
At cruise FL360. I was PM (Pilot Monitoring) and Captain was PF (Pilot Flying). left engine developed severe vibrations and roll back of at least 20% N1. Captain elected to reduce power on Engine 1 and descend to FL240. Engine stabilized at FL240 due to lower power setting used. Contacted Dispatch to get them to advise us on possible diversion should we have to shut down engine. They recommended ZZZZ. I started to look up other possible airports on Jepps as ZZZZ diversion at night in mountains Single Engine was probably not advisable; but no airport charts were available for country Airports in the database. Since the engine was stable we elected to continue to ZZZ. On final in ZZZ the left engine developed more vibrations. PF elected to keep it at idle and we performed a Flap 15 landing. On taxi-in; the 'Left Engine Oil Bypass' light came on.During flight the FDR INOP light came on/off a few times as wellFlight attendants and passengers were continuously kept in the loop throughout the event and FME was in the cockpit.As we mostly fly to Region right now; perhaps having a database in Jepps for all airport would be important so that we would have options for diversions should a problem occur in flight.
Air Carrier flight crew reported missing Jeppesen charts for an entire country during a diversion.