B737-700
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 167; Flight Crew Type 15000
Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Other / Unknown; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Issued New Clearance; Flight Crew Overcame Equipment Problem; Flight Crew Took Evasive Action
Aircraft; Weather
On climbout; a bright flash of light happened; followed by a 3.5 percent throttle split. The number 1 engine came back to 94.2 and number 2 engine stayed at 97.8. The radios had a static sound for about 2 to 3 minutes. The FO and I thought this was weird; since the auto throttles were engaged. I disconnected the auto throttles and aligned the throttles back up; and reengaged auto throttles. From this point forward the auto throttles did not work. The next thing was when we approached our initial level off altitude the aircraft had no indications of leveling off; so I intervened and leveled off. Basically; we were in CWS Pitch. This is when we noticed we had no vertical autopilot control or no flight director. We were still in the WX so when ATC offered us a higher altitude we took the new altitude to get us out of the WX. The FMC and CDU lost all route wind data; and would not accept any new information or data. We also lost some inputs on the Center instrument panel. I flew the next hour and 25 minutes without the autopilot in the WX; but in smooth air. Flying point to point; another bizarre occurrence was before the bright flash the FMC said our maximum altitude was FL410 and the optimum altitude was FL406; after the occurrence the FMC said our maximum altitude was FL398 with no optimum listed. We checked the weight and fuel load with the loadsheet with the OPC's Max/Optimum; and it agreed with the original information - 122.8 was our weight 12.8 was our fuel and ZFW was 110.0 from the loadsheet. I decided to be conservative and level off at the first smooth altitude we reached; and we appeared to be between layers. We informed ATC that we had lost our autopilot and FD; and we could not descend via the [arrival]; but we could fly the track manually. Landed safely; called MX and wrote the autopilot and FD up in the logbook as a static discharge event.
PM looked for popped circuit breakers (none); reviewed the QRH; and reviewed the AOM (Aircraft Operations Manual); nothing matched our malfunction indications. At this point the PF and PM concurred that all pitch modes on the MCP were inoperable; the auto throttles were inoperable; the AP would only engage in LNAV/CWS Pitch; we were missing probe and computer data in the FMC and on the Engine display; and the FMC would not accept airspeed or altitude inputs. PM informed ATC of our malfunctions and asked for alternate descent instructions to the terminal environment. ATC supported us and provided manual descent profile and vectors to an uneventful visual landing. We called for MX to meet us at the aircraft and both MX and PF/PM did a walk around searching for indications of a possible lightning strike.
B737-700 flight crew reported they lost the flight directors and autopilot following a static discharge.