Originally Posted by
aviator1970
As per my experience even changing the data frequency to an unused frequency wont help as in most cases the system uses SATCOM to communicate automatically in case no VHF handshake takes place.... reracking etc is impossible in air too!!!
In the case of the 777, there is a way to choose only VHF or only SATCOM. If the frequencies are jiggered, the ACARS transmissions will fail. As far as de-racking, the ACARS VHF modem LRU's are fully accessible in the EE bay, however I doubt this was the method used - I was only offering this as a possibility as given to me by a friendly tech.
The ACARS data path choice, by the way, is there primarily due to uplink/downlink costs - it is always cheaper to use VHF.