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inally, I guess English isn't your native tongue, but curbed and idling are not aviation terms and PBM is an acronym I'm not familiar with. You'll get more credibility using correct terminology so please get that right in your report. By idling I imagine you mean holding - (wasting time flying in circles) but doing this on GPS is no different to using a beacon fuel wise.
Sorry, i meant curved, not curbed. Have you heard of that? if not:
Boeing 747 and Airbus A380 Aircraft News from Flightglobal
And to be able to do such a landing with accuracy, you need to use GPS, and really accurate wind data from atc. This is sophistiquated stuff.
This differs in a positive way from regular "green" approaches, gliding in a straight approach (sometimes over places where people live) with engines idling (sure you never heard of that..?)