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Old 16th Jan 2009, 16:32
  #53 (permalink)  
mcdhu
 
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John gives a nice and simple exposition on climb speeds for jet ac which I (think I) understand. But can anyone - and I guess I hope JF reads this - explain why, in the normal course of events (A320 Series, crz around FL350+, CI 12, mid weight) the climb IAS/Mach will be roughly 285/.77 with the usual crossover level around FL300 and yet on the short flights LGW/LTN/STN to AMS/CDG which are capped at FL230 the climb IAS is high - 300ish which converts to the climb/crz Mach of .65ish at around FL180 so you end up cruising at a ridiculous IAS of around 250-260. I understand why the ac wants to cruise at such a low IAS, but why does the FMGC want to climb at such a high IAS which it then drags back using Mach No to the required low value.

A good read!
Cheers
mcdhu
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