Timeline/Pre-Flight/1554:31 UTC
< Timeline | Pre-Flight
Event Summary
23:54:31 MYT Friday, 7 March 2014
Malaysia Airlines Operations Centre contacted MH370 by sending an ACARS message (over VHF) suggesting that VHF3 be switched (from data) to voice if the SATCOM system was operational (serviceable). Future communications to and from the aircraft by ACARS would then be (automatically) sent via the SATCOM system.
Event Details
Safety Investigation Report MH370/01/2018 Appendix 1.9A
Time
15:54:31Trans
46817955Direction
Outgoing UplinkAN
9M-MROFI
MH0370Medium
KULMachine
MHKULKJACM001Raw DTG
071554SMI
CMDApplication
RELAYStatus
Uplink SentMessage Type
Frequency Auto-tune -- Frequency Auto-tune B777Source/Destination
BKKXCXA
Time
15:54:31Trans
46817955Direction
Outgoing GroundAN
9M-MROFI
MH0370Medium
KULMachine
MHKULKJACM001Raw DTG
071554SMI
CMDApplication
BATAPCNXStatus
RoutedMessage Type Source/Destination
BATAP_TO_MSW
Time
15:54:36Trans
46817955Direction
Incoming DownlinkAN
9M-MROFI
MH0370Medium
KULMachine
MHKULKJACM001Raw DTG
071554SMI
MASApplication
RELAYStatus
NormalMessage Type
MAS-S (successful)Source/Destination
BKKXCXA
Notes
- ACARS can send data via the satellite communications system (SATCOM) or over a VHF data-link. The VHF radio must be switched from voice to data for this to occur.
- VHF radio is commonly used for data at or near an airport, where the service provider has a transceiver to provide the ACARS service.
- It seems that for flight MH370, ACARS was initially communicating via VHF.
- This message from Malaysia Airlines Operations Centre suggests that the VHF radio be switched to voice-only, using channel 131.550 MHz - if the SATCOM is serviceable, meaning that the SATCOM could transmit and receive future ACARS messages.
- This ACARS message was included in the Safety Investigation Report MH370/01/2018 Appendix 1.9A but not in the previous version Factual Information MH370/01/15 Appendix 1.9A.