in some airport like narita in japan, the effort for noise reduction from aviation industry is seriously implied.
airport curfew will start at 22.00 till 05.00 meaning no take off and landing allowed unless as otherwise approved by authority.
any aircraft being parked at bay where fixed ground external power readily available shall use this facility and therefore APU is no longer reqd (however if need be, APU may be used if approved by authority and time usage shall be minimised)
end result : neighbourhood surrrounding airport is happier than ever
