Timeline/NIO-SIO/0819:37 MYT

MH370 DECODED
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Event Summary

08:19:37 MYT Saturday, 8 March 2014

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SATCOM Log-On, successfully completed

  1. The SATCOM link becomes available (for voice and data – Class 3) once more and normal SATCOM operation resumes.
  2. No Flight ID was sent to the GES during the Log-On. This infers that the SDU was still not receiving the Flight ID from AIMS.


Event Details

  1. Safety Investigation Report MH370/01/2018 Satellite Ground Station Logs - Key Observations

    SATCOM Log-On, successfully completed

    1. The SATCOM link becomes available (for voice and data – Class 3) once more and normal SATCOM operation resumes.
    2. No Flight ID was sent to the GES during the Log-On. This infers that the SDU was still not receiving the Flight ID from AIMS.
    3. The possible reasons for the link loss and the subsequent Log On that took place at 0019:00 have been investigated and are detailed in Section 2.5.2. There are many quite complicated scenarios that could have caused the 0019:00 Log-On with no Flight ID. However, the most likely reason is a power interrupt to the SATCOM avionics, of a duration less than 8 minutes.
    4. The GES recorded an abnormal frequency offset for the SATCOM Log-On Request and Acknowledge transmissions (see Sections 1.9.5 para. 5) and 2.5.3). The abnormal BFOs for the 0019 Log-On Request and Log-On Acknowledge are more likely due to a combination of uncompensated vertical velocity (descent) and OCXO warm up drift.
    5. The IFE did not subsequently establish the two Data-3 X.25 connections over the SATCOM, which it normally does if it is functional. It can be inferred that the IFE was either not operating at this time (powered off, not being powered whilst the SATCOM was being powered by the APU, failed, or still resetting after a power cycle), or the SATCOM and/or the IFE became inoperative before the IFE was able to establish the Data-3 connection


    Note: This is the last transmission received from the aircraft terminal.




Notes

  1. Source: Safety Investigation Report MH370/01/2018 2.5.1 Summary of Key Observations of the SATCOM Ground Station Logs

    12) The last transmission received from the SATCOM occurred at 0019 on 08 March 2014 and the SATCOM failed to respond to a series of three Log-On interrogations starting at 0115 on 08 March 2014. This implies that the SATCOM probably became inoperative at sometime between 0019 and 0115 on 08 March 2014.