Would it be possible to have as a selectable field in the 'Endorsement restrictions' of the scheduler a menu item that links the crew endorsement to the aircraft type.
This would need to be a two way relationship. I.e. if I scheduled a pilot first, and then select the aircraft it should only present me the aircraft that the selected pilot is endorsed on, and in the opposite sense, if I schedule an aircraft onto a task and then I go and add a pilot/s it should only presents me with the pilots that are endorsed on that selected aircraft type.