From what I know,you will save fuel arriving asap at cruise level.On the 737 the best rate climb is around 250 kts.The 737 is capable of high ROC,and we use 250 bellow FL100 ,which usually give 3000-4000 feet/min ROC ,and accelerate to around 290-300 kt (CI -30) over FL100 with a resultant ROC of around 2000-2500 f/m . This way we can exit fast the TMA, and get shortcuts in busy airspace,like LHR,FCO,CDG,VIE..
One other point -after few bird strikes at low altitude with high speed, they'll change for sure this policy. Do a serarch for the AA 767 in CDG ,bird strike years ago,resulting in depressurization ,at FL120 ,right after acceleration. Or ,are there no birds in Asia?
