Flight Crew Multiengine; Flight Crew Flight Instructor; Flight Crew Instrument
Flight Crew Last 90 Days 50; Flight Crew Total 16000; Flight Crew Type 225
Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Other / Unknown
Flight Crew Overcame Equipment Problem
Human Factors; Aircraft
We were flying at FL430 when the Flight Attendant notified crew that there was a flood in the lavatory. Captain went back to investigate while First Officer flew aircraft. Owner went up to flight deck and hit his head on emergency electrical gang bar in cockpit. All electrical power was lost and cabin began depressurization. Captain returned to flight deck and tried to reset electrical power and began emergency descent. We could not notify [Center] of our descent because our radios were inoperative due to electrical power unable to restore. Passengers and flight crew all donned O2 masks except owner; who passed out due to hypoxia. Captain was finally able to restore electrical power at 16;000 FT. First Officer was now able to contact...Center and advise of the situation. We were able to then land. In the future no one except flight crew is allowed to enter flight deck during flight; not even aircraft owner. One good thing that happened was that both pilots had iPads. We were able to still navigate even though aircraft lost electrical power. The IRs and navigation boxes were not able to power up for the rest of the short flight.
[Narrative #2 contained no additional information].
At FL430; owner of a GIII hit his head on an electrical gang bar in the cockpit causing loss of electrical power and cabin decompression. Electrical power restored at 16;000 FT and aircraft landed without further incident.