In March 2014 , ACARS messages and Doppler analysis of ACARS satellite communication data played a very significant role in efforts to trace Malaysia Airlines Flight 370 to an approximate location . While the primary ACARS system on board MH370 had been switched off , a second ACARS system called Classic Aero was active as long as the plane was powered up , and kept trying to establish a connection to an Inmarsat satellite every hour
Malaysia Airlines Flight 370
Malaysia Airlines Flight 370
ACARS