Fatal Accident (38) – Boeing 727-22C, N7434U, 12 miles west of Los Angeles, CA (Santa Monica Bay), January 18, 1969
OFFICIAL PRELIMINARY REPORT: Report Not Available Yet
OFFICIAL FINAL REPORT: https://www.ntsb.gov/investigations/AccidentReports/Reports/AAR7006.pdf
SOURCE Report:
United Air Lines Flight 266 was a scheduled domestic passenger service operating from Los Angeles International Airport (LAX) to Milwaukee, Wisconsin, with a stopover in Denver, Colorado. The aircraft involved, a Boeing 727-22C registered as N7434U, had been in service for only four months and had accumulated 1,036 flight hours. On January 18, 1969, the flight departed Los Angeles at 6:17 p.m. Pacific Standard Time. Shortly after takeoff, the aircraft encountered a critical electrical failure, leading to its crash into Santa Monica Bay approximately four minutes later, killing all 38 people on board, including six crew members and 32 passengers.
At the time of the flight, the aircraft’s number three generator had been non-functional for several days, a condition permissible under Federal Aviation Administration (FAA) guidelines provided that certain operational precautions were taken. The crew, consisting of an experienced captain with over 13,600 flight hours, a first officer, and a flight engineer, followed standard procedures for operating with two functioning generators. Approximately two minutes into the flight, an engine one fire warning prompted the crew to shut it down. This action left the aircraft reliant on the number two generator, which subsequently failed for reasons undetermined. The loss of electrical power disrupted critical flight systems and left the crew unable to navigate effectively in the night sky.
Multiple witnesses on the ground reported observing sparks near the rear of the aircraft during takeoff, though no conclusive evidence linked these observations to the subsequent power failure. The cockpit voice recorder (CVR) and flight data recorder (FDR) captured limited information due to the electrical loss. Recovery operations from the crash site, located in 930 feet of water, revealed severely fragmented wreckage, further complicating investigative efforts. The lack of recovered cockpit instruments limited the ability of investigators to analyze specific causes of the generator failures and other anomalies reported during the flight.
The investigation, led by the National Transportation Safety Board (NTSB), explored multiple hypotheses regarding the failure of the backup electrical system. One possibility involved inadvertent deactivation of the battery, either through crew error or system malfunction. Another theory posited that the flight engineer may have misconfigured the essential power switch, leaving the standby electrical system inactive. The NTSB ultimately identified deficiencies in procedural guidance for handling generator failures, noting that the United Airlines checklist did not explicitly instruct the crew to switch to backup power.
The flight control system, which operated hydraulically, remained functional during the electrical failure. However, the loss of cockpit lighting and instruments rendered the pilots spatially disoriented. Without visual or instrument-based references, the aircraft entered an uncontrolled descent, impacting the ocean at a steep angle. Tests conducted after the accident suggested that an overload condition on the number two generator could have led to its failure following the shutdown of the number one generator, though this hypothesis could not be definitively proven.
The NTSB concluded that the probable cause of the accident was the crew’s loss of altitude orientation during a night, instrument-dependent departure in which all attitude instruments were disabled by the electrical power loss. The final report also highlighted the lack of a battery-powered backup system for critical flight instruments, which was not a requirement for transport-category aircraft at the time. This accident, along with others involving similar deficiencies, led to regulatory changes mandating independent power sources for essential instrumentation on commercial aircraft.
The aftermath of the accident spurred significant industry-wide changes in both equipment standards and operational protocols. The FAA implemented stricter requirements for standby power systems and revised procedural checklists to ensure clear guidance for managing electrical failures in flight. These measures aimed to prevent similar accidents by addressing both technological and human factors contributing to electrical system failures.
United Air Lines Flight 266 remains a pivotal case in aviation safety history, illustrating the critical importance of robust electrical systems and comprehensive procedural training for flight crews. The insights gained from this investigation have informed ongoing efforts to enhance the safety and reliability of commercial aviation systems worldwide.
Aircraft Operator:
United Airlines
Video(s):
https://www.youtube.com/watch?v=K3NBfH12YtY
Accident Location:
Fatal Accident (38) – Boeing 727-22C, N7434U, 12 miles west of Los Angeles, CA (Santa Monica Bay), January 18, 1969
33°56′56″N 118°39′30″W (https://g.co/kgs/uLmjPZY)
ASN:
https://asn.flightsafety.org/wikibase/331630
FAA/International Registration:
N7434U (https://registry.faa.gov/AircraftInquiry/Search/NNumberResult?nNumberTxt=7434U)
Year of Manufacture:
1968
SN/Military Registration/BUNO:
19891/631
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National Report(s):
Archived
Local Report(s):
Archived
Image Reference(s):
https://upload.wikimedia.org/wikipedia/commons/thumb/0/0c/United_Airlines_Boeing_727-22_N7029U.jpg/548px-United_Airlines_Boeing_727-22_N7029U.jpg
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