Safety Concerns,
I shouldn't have said "a few seconds all the way to france." I should have said a few seconds to the
First Downlink Ground Station.
Indulge me for a moment, will you? My point is not what happens after the ground station gets the message. I don't care. You're right. Anything could slow down then. My point is that from my readings, the satellite will not even send the message AT ALL, NOT ANYWHERE until it gets a C31A confirmation transmission from the aircraft. This means TWO transmissions have to come from the aircraft ON EVERY ACARS REPORT before the satellite will decide it's error-free, and then put that stamp of approval (C31A) on the SITA message and THEN (AND ONLY THEN) beam it down the first ground station and THEN is could get delayed. The fact that it exists testifies it passed the ACARs programing protocol.
Wouldn't you say?
7.3 Response Time [1973 - CC]
The average response time for Type A messages, i.e. the time lapse between the Instant an operator presses the transmit key of his terminal to send his query and the instant the first character of the reply appears on the screen (see Figure 6) ranges from 1.4 seconds to 3 seconds, depending on the number of links involved in route. A typical response time distribution is shown in figure 9.
7.4 Satellite Processors
The downtime of SPs is around 16 hours per month including scheduled and unscheduled stops (e.g. preventive maintenance, configuration changes, etc.)
Presently, certain SPs switch up to 6 message blocks per second during peak conditions of traffic.
Switching times are in the order of 5 ms per block for both systems.