Originally Posted by DWS
Does anyone here KNOW how often the ACARS- system on a 777 or on this 777 pings absent a response or ( contract ) to supply engine related data?
Note that BA claims no such contract- and RR also claims no ( engine? ) data after a few minutes before transponder shut down.
I suspect that some technical types consider DATA only to be ( engine parameters and the like ) and the non technical types do NOT consider a simple ping to be DATA … or vice versa depending on background.
And about 99 percent of the media pundits don't know the difference.
So when RR says NO engine data - they **probably mean ** no engine parameters- and do not count a ping per se as DATA
The press probably thinks or defines NO DATA as being NO pings
Yes its splitting hairs or whatever- but his old engineer would consider the ping as " hello- are you there " as an address or attempt to communicate and NOT DATA as its commonly used. I would consider altitude and speed and time as general DATA and Engine parameters as " engine " data .
Lacking one ( engine ) data IMO does NOT mean NO DATA if altitude and speed are part of the transmission.
Back to my question does anyone KNOW the ping repitition rate or ( try every xx minutes or seconds and if no answer to dump data, try again in xx minutes ) ???
I know literally nothing about the SATCOM system on the 777, but my take on the situation is that it is similar to cell phones. You can have a cell phone that is not
subscribed to any service, however it is still going to "ping" the towers and attempt to register with the network and get online. The network will reject it (as the radio/customer is not subscribed), but they would theoretically have a record of the IMEI/SIM identifier sent to them during the registration process. So, I don't think there is any contradiction here. Assuming the A/C was equipped with the SATCOM radio, whether or not it was actually subscribed, it was likely attempting to join the network on a regular basis. Perhaps as part of the registration header, the A/C sends it's current position (maybe to assist in locating the correct satellite or ground gateway) - but does not successfully register due to lack of subscription. This would corroborate a statement from both RR & Boeing's saying they didn't receive any information from the customer, as well as the fact that the provider (Inmarsat? or whomever it is) received "data" from the plane.