Time:1250:19 UTC/Notes

1. The aircraft systems were powered on before the arrival of the Flight Crew.
2. The SATCOM system would have initiated the Log-On request automatically, and used the Pacific Ocean Region I-3 satellite because that was how it was configured when previously shut down.
3. The Inmarsat Ground Earth Station is located near Perth in Western Australia. This GES communicates with satellites in both the Pacific Ocean Region and the Indian Ocean Region.
4. The data sent did not include a Flight ID because that information had not yet been entered into the system.
5. BFO and BTO data is not available because the first entry in the Data Communication Logs is at 1559:55.413 UTC (2359:55.413 MYT 7 March)
6. The aircraft was on the ground. This event at 1250:19 UTC (2050:19 MYT Friday, 7 March 2014) is the first Satcom activity since 0802:27 UTC (1602:27 MYT Friday, 7 March 2014).

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Later SDU Log-On messages are typically followed by an ACARS message as it re-establishes a datalink over the SATCOM system. However, at this time it is probable that ACARS was still switched to VHF.

See Time:1554:53_UTC where ACARS 'Lost VHF'.

Satellite Communications

Ground earth station. A satellite ground station sends or receives data from orbiting satellites. (Source: ATSB)

Flight Identifier, for example MH370

Burst frequency offset. BFO is a measure of the difference between the expected frequency of a satellite transmission and the frequency received at the ground station. (Source: ATSB)

Burst Timing Offset. BTO is a measure of the time taken for a satellite transmission round trip (ground station to satellite to aircraft and back) and allows a calculation of the distance between the satellite and the aircraft. (Source: ATSB)

Coordinated Universal Time

Malaysian Time (MYT) is Coordinated Universal Time (UTC) + 8 hours

Satellite Data Unit

Aircraft Communication and Reporting System

Very High Frequency

ACARS lost data link over VHF (disconnected)