I’m not sure if this helps but another meaning for IP would be initial point. This was a term used in WWII. it referred to the spot a bomber would begin it’s bombing run at. The bombsites of the day required a period of straight and level flying to be adjusted for accurate results.
Same is true today, all CAS uses an IP as well as all helo routing.
https://www.youtube.com/embed/ie3SrjLlcUY
attention all WWII flying freaks -
extexasredhead sent me this AMAZING video of an American pilot
flying a Spitfire over Germany UNarmed.. alone...
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from your post (initial point. This was a term used in WWII. it referred to the spot a bomber would begin it’s bombing run at. The bombsites of the day required a period of straight and level flying to be adjusted for accurate results.)