MIAMI — The ongoing search for the Malaysian Airlines Boeing 777 that disappeared on March 8 is the topic of “The Search for MH370,” a paper written by Inmarsat and the Royal Institute of Navigation. The paper focuses on how the search shifted after satellite signals from the aircraft were analyzed.

Inmarsat is part of an industry working group that is trying to locate the 777 that disappeared somewhere over the Gulf of Thailand. The paper, published October 8 by the Royal Institute of Navigation’s peer-reviewed journal, explains how Inmarsat, working with the international investigation team, researched and analyzed the satellite signals, which contributed to a shifting of the search area from its original location to the area which is now the focus on attention.

Subsequent analysis of signals transmitted by the 777’s satellite communications terminal to Inmarsat’s 3F1 Indian Ocean Region satellite indicated that the aircraft continued to fly for several hours after loss of contact, resulting in the search moving to the southern Indian Ocean. The paper analyzes the satellite signals that resulted in the change of the search area.

“The first deduction that can be made from the signaling data is that the aircraft remained operational for at least seven hours after the loss of contact, as the satellite terminal continued to transmit messages during this period,” according to the paper.  “It may further be deduced that the aircraft navigation system was operational, since the terminal needs information on location and track to keep its antenna pointing towards the satellite.”

The analysis presented in the paper indicated that MH370 changed course shortly after it passed the northern tip of Sumatra and traveled in a southerly direction until it ran out of fuel in the southern Indian Ocean west of Australia. “A potential flight path has been reconstructed that is consistent with the satellite data, indicating a last contact location of 34·7°S and 93·0°E, but it is stressed that the sensitivity of the reconstructed flight path to frequency errors is such that there remains significant uncertainty in the final location,” said the paper.

“This important paper on one element of the search for MH370 has been made freely available to all under Open Access arrangements,” said Nick Randall, editor-in-chief of The Journal of Navigation. “The Royal Institute of Navigation and publishers Cambridge University Press normally charge for subscription to The Journal of Navigation, but we feel this paper and subject are too important, and that it should be shared with the world.”

Australia Continues the Search

Meanwhile, the Australian Transport Safety Bureau (ATSB), which has taken the lead on the search for MH370, reported on October 8 that all the available data indicates the aircraft entered the sea close to a long, but narrow arc of the southern Indian Ocean. The three vessels currently being used for the search are being funded by  Malaysia and Australia.

The vessel GO Phoenix arrived at the search area on October 6 and will continue its operations for 12 days before sailing to Fremantle to be resupplied. Fugro Discovery arrived at the Port of Fremantle on October 5, and search equipment and a mission crew are being mobilized for an estimated departure of October 11. And Fugro Equator is currently surveying the search area and is expected to complete its work by the end of the month.

Refinements to the analysis of both the satellite and flight data have been continuing since the loss of MH370, said ATSB. The analysis has been undertaken by a team from the UK, US, Australia and Malaysia working both independently and collaboratively.

“The latest analyses indicate that the next, underwater, phase of the search should be prioritized further south within the wide search area,” said ATSB. “Work is continuing with refinements to the analysis of the SATCOM data. This ongoing work may result in changes to the prioritization and locale of search activity over the period of the underwater search.”