[cynwoody]

If the airplane’s satellite link was working, why wasn’t the Rolls-Royce engine health monitor also working?

[CedarDave]

If the airplane’s satellite link was working, why wasn’t the Rolls-Royce engine health monitor also working?

Exactly UNLESS they were separate services. See post 25.

[Izzy Dunne]

why wasn’t the Rolls-Royce engine health monitor also working?

What make you think it wasn't?

It doesn't send data continuously; it sends at "significant events" (takeoff, achieving cruise), or every 30 minutes.

If the plane nosedived into the water, the monitor might not be able to transmit after that.

If it exploded, it might not be able to transmit.