Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 20; Flight Crew Total 2750; Flight Crew Type 635
Aircraft Equipment Problem Less Severe; Flight Deck / Cabin / Aircraft Event Other / Unknown; Inflight Event / Encounter Weather / Turbulence
Flight Crew Diverted; Flight Crew Landed As Precaution; General Maintenance Action
Aircraft; Weather
While in cruise westbound at FL260; briefly transiting [foreign] airspace; a single turbulence bump was encountered and the pilot's headset impacted the overhead switch array. Simultaneously both radio bus fail lights illuminated; and GPS/NAV/COM/Transponders were without power. We were in VFR conditions at the time; had just passed the ZZZ airport which was clearly in sight; and we attempted to restore power to the radio busses; including resetting the overhead switches; cycling battery power off and on; pulling all load from the busses and attempting to reset the busses or tie and crossfeed the busses with no load devices attached. We maintained VFR and turned on a handheld VHF transceiver and had intermittent COM with [foreign] Center; transmitting in the blind that we had lost electrical power and would be descending. We circled the area while troubleshooting; achieved contact with ZZZ Tower; asked them to advise [Foreign] Center we were OK; that our intention was to proceed VFR to ZZZ2 and land there; but again COMS with the handheld were somewhat intermittent. We proceeded VFR at about 6;300 feet near ZZZ1 and were able to achieve good COMS with their tower; explained the situation; that we were OK and able to fly normally and asked them to advise ZZZ2 tower we were inbound. We transitioned COMS to ZZZ2 routinely; entered the VFR pattern and landed safely.On the ground after shutdown the radio busses fully recovered and we were unable to recreate the dual bus failure. After much testing we continued our flight; with the pilot's seat rolled back enroute to prevent the possibility of any recurrence of the headset strike on the overhead; and kept breakers pulled on certain non-essential high current equipment (HF radio; etc). The overhead switches will shortly be checked at an appropriate maintenance facility.We believe we handled the situation to the best of our ability; with primary focus on maintaining flight control of the aircraft; secondary focus investigating recovery from the fault; communicating to the best of our ability with ATC on backup equipment; and electing to land promptly in VFR conditions on US territory.
AC695 pilot reported losing much of his electrical power after bumping his head on the overhead panel in turbulence.