Date: August 28, 1973
Type: Boeing 707-331B
Registration: N8705T
Operator: Trans World Airlines
Where: Los Angeles, California
Report No. NTSB-AAR-74-8
Report Date: July 10, 1974
Pages: 43

A Trans World Airlines, Inc., Boeing 707-331B porpoised while descending 
approximately 35 miles west of Los Angeles, California, at 2150 p. d. t. 
on August 28, 1973. The flight was bound for the Los Angeles 
International Airport.

The longitudinal instability persisted for about 2 minutes during which 
more than 50 pitch oscillations occurred. Peak acceleration forces of +2. 
4g to -0.  3g were measured at the aircraft's center of gravity.

There were 141 passengers and 11 crewnlembers aboard. As a result of the 
accident, one passenger was injured fatally; one flight attendant and two 
other passengers were injured seriously.

The National Transportation Safety Board determines that the probable 
cause of this accident was a combination of design tolerances in the 
aircraft's longitudinal control system which, under certain conditions, 
produced a critical relationship between control forces and aircraft 
response. The atypical control force characteristics which were present 
in this particular aircraft's control system were conducive to 
overcontrol of the aircraft by the pilot.  The pilot's normal reaction to 
an unexpected longitudinal disturbance led to a pitching oscillaticn 
which was temporarily sustained by his subsequent application of control 
column forces to regain stable flight.