Timeline/Pre-Flight/1250:19 UTC

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Event Summary

20:50:19 MYT Friday, 7 March 2014

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The Satellite Data Unit (SDU) on Malaysia Airlines Boeing 777 registered 9M-MRO initiated the first of several Log-On requests to the Inmarsat satellite communications system.
The transmission was relayed via Inmarsat's Pacific Ocean Region I-3 satellite to the Ground Earth Station (GES) near Perth in Western Australia.

Event Details

  1. Safety Investigation Report MH370/01/2018 - Table 1.9C - Chronology of Satellite Communications Ground Station Logs

    No. Time (UTC) Key Observations - Satellite Ground Station Logs
    1. 1250:19 Prior to take-off, the SATCOM initiates a normal Log-On as Class 1 (data only capable) via the Pacific Ocean Region (POR) I-3 satellite, using the Low Gain Antenna (LGA) subsystem, suggesting that ADIRU (Air Data Inertial Reference Unit) navigation data was not available to the SDU at this time. No flight ID is sent to the GES at this time. This is the first SATCOM activity recorded at the GES since 0802:27, suggesting that the SATCOM was not powered for a period of several hours, whilst the aircraft was on ground. This is quite normal.


  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).