When RAAS was first installed on the FedEx fleet there were problems due to the volume (non-adjustable) of the RAAS advisories. It would be louder than those over the VHF, so while you were getting the "approaching runway two seven left" advisory crews were missing the line up and wait or cleared take-off instruction from ATC. Same problems on landing with the "four thousand remaining" etc drowning out the ATC instructions.
I don't think FedEx ever removed it, just deactivated it until Honeywell had sorted the problem, which I think they now have.