Being former AF, it took me a while to get my arms around this topic. I try to keep things simple. TERPS deals with rules for laying out airspace during departures and arrivals. OEI data is specific to each aircraft. It would be cost prohibitive to build departures which guarantee obstacle clearance for every type of aircraft out there. SDPs are great but are normally not economically feasible unless an operators operates at an airfield on a regular basis. The AF doesn't want to pay for SDPs unless they have to.

Also, the USAF has been very gun-shy about TERPS issues and using Jepps since they lost the CT-43 in Dubrovnik and the C-130 in Jackson Hole. Problem with the Jepps for the AF is not so much that their database was out of date, but that the AF could not verify that it was--especially for some more out-of-the-way airfields overseas. The funny thing is that AMC's databases are probably more out of date than the Jepps, since they have to independently verify procedures overseas and do not have the manpower to do so. Result--a waiver to operate--many times using Jepps procedures. I'm retired now, but when I was flying in the AF, I found more mistakes in DoD books than in Jepps.