The fsx_sdk_sp1.exe file you have requested: Official / Patches / Flight Simulator X Deluxe SDK Update - 89.97mb is not available. Perhaps try browsing all files for the game Flight Simulator X and upload any files you want to share or are missing. This is the only information we could locate:
Microsoft Games has issued an update for the SDK included with the Deluxe Edition of Flight Simulator X. It includes improvements to almost all aspects of the SDK and it requires the original SDK to be installed.