United Air Lines Flight 266Saturday January 18, 1969
The aircraft crashed into Santa Monica Bay shortly after a night takeoff in poor weather and visibility. The aircraft was dispatched with the No. 3 generator inoperative. While this was allowed, United was required to repair the generator at the first airport where there were repair facilities. The aircraft flew for a total of 41 hours with the inoperative generator passing through airports that had the facilities to repair the generator. Soon after taking off, the crew reported a fire warning in the No. 1 engine and shut it down as required. For reasons that could not be determined, shutting down the No. 1 engine and it’s generator tripped the No.2 generator resulting in the loss of all electrical power in the aircraft. Following loss of all electrical power, the battery standby electrical system either was not activated or failed to function. Electrical power at a voltage level of approximately 50 volts was restored approximately a minute and a half after loss of the No. 2 generator. The duration of this power restoration was just 9 to 15 seconds. Regardless, the pilots did not have functioning attitude indicators from the time the No. 2 generator tripped. In the dark, with no outside or inside reference to guide them, the pilots became spatially disoriented and the plane eventually went into a dive and crashed into the Pacific Ocean 11.3 miles west of the airport and sank in 950 ft. of water. The accident was caused by the loss of attitude orientation during a night, instrument departure in which all attitude instruments were disabled by loss of electrical power. The investigation was not able to determine (a) why all generator power was lost or (b) why the standby electrical power system either was not activated or failed to function." One unproven scenario that is not contradicted by available evidence was the inadvertent placement of the battery switch to the "OFF" position by the flight engineer during attempts to remove galley loads from the generator buses. The galley switches were similar in shape and size, and were located on the flight engineer's upper panel in close proximity to the battery switch. Following the accident, the flight engineer’s panel was redesigned to place a guard over the battery switch.