Malaysian Airlines MH370 contact lost

[Communicator]

ACARS Access

There seem to be three separate issues in connection with ACARS that MAS senior management has been unclear about:

1. Human Messaging through ACARS

When MAS talks about ACARS, they are probably viewing it from a layperson's perspective: No HUMAN OPERATOR received/sent any messages through ACARS.

2. Automatic Messaging through ACARS

It seems that some system status information was successfully sent to Rolls Royce and to Boeing, presumably through ACARS. These transmissions occur only when triggered by specific conditions (e.g. engine start/take off). It is not clear when the last transmission from MH370 was received.

3. ACARS Link Establishment

Apparently, the ACARS Satcom "pings" a satellite at regular intervals (hourly?) to establish contact and download incoming messages (if any). Unless messages are actually sent or received, this link establishment or "ping" information would only be available to the ACARS system operator, NOT to MAS, Rolls Royce or Boeing.

Ollie Onion's post above indicates that Satcom "pinging" would occur even though MAS may not have subscribed to the Satcom options for ACARS.

It seems that U.S. Government statements were referring to these Satcom pings, NOT to full messages. (Of course, anyone familiar with the detailed workings of the system would have tried to ascertain the ping log on Day 1.)

NOTE: Similarly, there has been no official recognition of the potential that cell phones left active established contact with ground-based cell towers if/when the plane crossed peninsular Malaysia (and Sumatra). Also, ADS-B messages may have been received by ground-based stations in those areas beyond those evaluated by FR24. All this would be of a piece with the apparent failure to check primary radar recordings at an early stage.