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- Under night, turbulent conditions, the flight experienced AC electrical failure.
- There Was a loss of control of the aircraft due to inadequate attitude reference.
- The specific cause of the AC electrical failure is unknown.
(b) Probable Cause
The Board determines that the probable cause of this accident was a loss of adequate attitude reference resulting from AC electrical power failure under night, turbulent conditions.
3. RECOMMENDATIONS
The Board believes that various modifications which have been accomplished in the instrumentation and electrical systems of the Lear Jet Since this acci- dent negate the requirement for additional recommendations at this time. Among the improvements was the installation of an attitude indicator powered by a source separate from the aircraft primary electrical system
BY THE NATIONAL TRANSPORTATION SAFETY BOARD
/s/ JOSEPH J'. O'CONNEIL, Jr. Chairman
/s/ OSCAR M. LAUREL Member /s/ JOHN H. REED Member
/s/ LOUIS M. THAYER Member
/s/ FRANCIS H. McADAMS Member
