MH370 burst frequency offset analysis and implications on descent rate at end of flight

On 7 March 2014 at 16:41:43Z,1 Malaysian Airlines flight MH370 departed Kuala Lumpur (KL) International Airport bound for Beijing. Less than an hour later, following the last recorded radio transmission from MH370 at 17:19:30Z, the plane's secondary radar transponder went offline. As evidenced by Malaysian military radar, the plane (registration number 9M-MRO) then veered off course unexpectedly, backtracked across the Malaysian Peninsula, and was tracked heading northwest from Penang through the Malacca Straits. After disappearing from radar at 18:22:12Z, it reestablished a satellite communications (SATCOM) link with the Inmarsat satellite I-3F1 at 18:25:27Z. By analyzing a series of automated messages exchanged via that satellite between the plane and an Inmarsat ground station in Perth, Australia, it was determined that the plane continued to fly for 6 h before finally ceasing message exchange with the ground station at 00:19:37Z on 8 March 2014. This article discusses specifically the analysis of burst frequency offset (BFO) metadata from the SATCOM messages. It is shown that the BFOs corresponding to the last two SATCOM messages from the plane at 00:19:29Z and 00:19:37Z suggest that flight MH370 was rapidly descending and accelerating downward when message exchange with the ground station ceased.