In the continuing saga of Malaysian Airlines flight 307 there was a bit of a bombshell dropped today when the Wall Street Journal reported that the Boeing 777‘s on board telemetry system continued to operate in a sort of “standby” mode for approximately 4 hours after the last confirmed radar contact with the jet.  The initial report was that monitoring systems embedded in the plane’s Rolls-Royce Trent 800 engines were emitting data, but the article was corrected to say that the plane’s satellite communications link was the origin of the signals.

Rolls-Royce Trent 800 High Bypass Turbofan engine on a Boeing 777

Modern aircraft are equipped with a digital datalink system called the Aircraft Communication Addressing and Reporting System (ACARS) whereby the aircraft sends packets of information about flight systems autonomously to ground crews.  The Wall Street Journal’s anonymous sources say that according to investigators the plane’s ACARS system, though not sending data, did send signals attempting to establish a link to communication satellites and this leads investigators to believe the plane was intact and still flying.  Official sources, however, denied the report.