In the Philippines' Civil Aviation Regulation Part 7, what does this part mean?
"first production aircraft" indicates the first aircraft built as part of the "production" run (as opposed to the ones built for the test phase, that are not part of the "production").

"under the type certificate" indicates that the type of aircraft has achieved certification and can be legally flown in the Philippines.

All together it identifies the first production built aircraft of a certain type after the certification was provided (in this case for the Philippines).