To make LINDA work with the PMDG P-8A Poseidon, all you have to do is add a single line to one of the configuration files. To do this, navigate to C:\...\<your FSX folder>\Modules\linda\aircrafts\PMDG 737NGX and open ident.lua with notepad. Below the line already present, add simfolder="PMDG 737" and save. Now LINDA (and thus the MCP Combo, should you have one) works with the PMDG P-8A Poseidon.