ACARS suggests lost plane flew for hours

Aviation Week this morning summarizes what we know about Malaysia Airlines Flight MH370. The Wall Street Journal has reported that the plane sent Aircraft Communications Addressing and Reporting System (ACARS) signals four hours after loss of radar and voice contact, when the plane's transponder was turned off, perhaps manually. Malaysia Airlines' CEO denies the Journal's report, saying no ACARS signals had been received since before radar contact was lost. (See related post.)

According to the New York Times, a “well placed official” said investigators are examining data that indicate the airliner maintained automated communication with satellite systems for hours after losing contact with ground controllers. The search has been extended into the Indian Ocean. The Times also reports that two communications systems were shut down at separate times, suggesting they were turned off deliberately rather than failing because of a catastrophic event.

The status of ADS-B is unclear. Aviation Week reports, “Surveillance over the South China Sea is improving, thanks to ADS-B systems that have been installed by several countries in the region.” However, it seems that ADS-B would not have been required for the route MH370 was flying. Malaysia is installing and testing two ADS-B ground stations through 2016; plans call for ADS-B to eventually be mandatory on planes flying some routes in the region.

Today, Aviation Week reports, airlines determine what data (such as ACARS) to monitor based on return on investment—not in order to locate a lost plane. The goal of Boeing's Airplane Health Management (AHM) real-time monitoring service is to help airlines predict when maintenance will be required and to have necessary parts available to minimize downtime.

Real-time streaming imposes bandwidth costs, but Aviation Week notes that costs could be reduced if the streaming were combined with Ka-band Wi-Fi, which in addition generates ancillary revenue.

Finally, the Times reports that military radar located a plane 200 miles northwest of Penang flying at 29,500 feet. Officials are investigating whether that plane could have been MH370. The plane had enough fuel onboard to fly at least 2,500 miles.