Old 28th Feb 2019, 09:35
  #36 (permalink)  
FlightDetent

Only half a speed-brake
 
Join Date: Apr 2003
Location: Commuting home
Age: 41
Posts: 2,566
Dixi188, the MTOW RTOW runs are done with brakes worn down to 25% and will cook them, as well as blow the tyres at the stop - it is a destructive test, agreed until this point. I haven't seen the numbers, so guessing here: the deceleration part eats about 1000 m.

The difference of opinions lies in how much of that actually applies for the overweight landing case in standard configuration. The approach speeds with landing flap tend to be 10% less than at liftoff, which alone provides a dramatic decrease of E(k) in the benefit of the return scenario. The pilots have all of the 3000m-ish runway at their disposal and there is no need to stop by the 1200 meters mark.

Thus our argument that destruction of the wheel assembly due to excessive braking energy does not enter the assessment matrix for an immediate landing at MTOW.
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