In September 1970 , members of the Popular Front for the Liberation of Palestine ( PFLP ) hijacked Kidnapping four airliners bound for New York City and one for London .

After the hijackers took control of the plane , several passengers and flight attendants learned from phone calls that suicide attacks had already been made by hijacked airliners on the World Trade Center in New York City and the Pentagon in Arlington County , Virginia .

The interface of the autopilot used on airliners was redesigned Reforming_a_system to make it more ergonomic .

The accident Catastrophe was the first fatal crash Catastrophe involving Cause_to_be_included an Airbus A321 , a long variant of the Airbus A320 family of short to medium range airliners .

Recommendations from the inquiry Scrutiny led to Causation the mandatory installation of cockpit voice recorders in British-registered airliners .